JP4452646B2 - Manufacturing method and initialization apparatus for optical information recording medium - Google Patents

Description

  The present invention relates to an optical information recording medium manufacturing method with high productivity and an initialization apparatus capable of high-speed initialization.

  Currently, a planar annular optical information recording medium having a rewritable phase change recording layer (for example, a CD-RW or a rewritable DVD, in this specification, the optical information recording medium is simply an optical disk, In some cases, it is called as a disk, a phase change type disk, etc.). In such an optical information recording medium, information is rewritten by reversibly changing the phase of the recording layer between a crystalline state and an amorphous state. Specifically, a method is generally used in which information is recorded by forming a recording layer in an unrecorded or erased state and forming an amorphous recording mark on the recording layer. The amorphous recording mark is erased by completely recrystallizing the amorphous mark. For this reason, the upper limit of the erasable linear velocity and hence the rewritable recording linear velocity are determined by the length of time required for the amorphous recording mark to be completely recrystallized.

  In recent years, recording media with an increased upper limit of the erasable linear velocity have been developed in response to a demand for improving the recording linear velocity. Specifically, in CD-RW, an optical information recording medium that can be rewritten at a linear velocity of 24 to 32 times speed is being realized or developed. In addition, in the rewritable DVD, an optical information recording medium that can be rewritten at a linear velocity of 4 times or higher is being realized or developed.

  In the manufacturing process of such an optical information recording medium, a recording medium obtained by forming a recording layer (in the present invention, a medium having a recording layer formed on a substrate is called a recording medium). For this recording medium, it is usually necessary to carry out an initialization process (initialized (unrecorded state)) with respect to this recording medium, which is referred to as an optical information recording medium. is there. Specifically, since the recording layer after film formation is usually in an amorphous state, the recording layer needs to be in a crystalline state in the initialization step (such initialization may be referred to as initial crystallization). ).

Initial crystallization is performed such that the linear velocity at all radial positions of the recording medium is constant in order to reliably crystallize the recording medium (Patent Documents 1 and 2). Specifically, the recording medium is irradiated with laser light for initial crystallization in a state where the recording medium is rotated so that the linear velocity is constant at all radial positions (Constant Linear Velocity: CLV method). Then, the light spot formed on the recording medium by the laser light is moved relatively in the radial direction of the recording medium, and the recording layer is crystallized.
JP 2001-236695 A JP 2003-272172 A

However, in the above-described conventional initial crystallization method, it is difficult to perform high-speed rotation speed control of the initialization device and the accompanying focus servo control, which may impose a great burden on the device.
That is, the above-described conventional initialization crystallization method needs to rotate from the innermost circumference to the outermost circumference in the recording layer of the planar annular recording medium at a constant linear velocity (CLV method). For this reason, the linear velocity determined by the maximum rotational speed at the innermost circumference of the initialization region is the maximum linear velocity of the initialization condition of the apparatus. However, according to the study by the present inventors, in an optical information recording medium in which rewriting is performed at a high recording linear velocity, initialization conditions at a higher linear velocity (specifically, about 25 m / s or more) are set. It has been found that the media performance may be improved by using it.

  The initial crystallization condition means that initialization may be performed at a higher linear velocity than the erasable linear velocity of the optical information recording medium. If an attempt is made to obtain good recording characteristics using such initial crystallization conditions, the initialization apparatus may be subjected to a heavy burden. This is because in such a case, if the conventional CLV method tries to improve the linear velocity, the mechanical durability of the disk becomes insufficient, the initialization device becomes large, and the cost of the initialization device increases. This is because a problem such as an increase occurs.

  That is, the following problems occur from the viewpoint of the mechanical durability of the disc. For example, in a CD or DVD, a polycarbonate resin is generally used for the substrate. From the limit of the mechanical strength of the polycarbonate resin substrate, the upper limit of the rotational speed during recording on a CD or DVD is usually about 10000 rpm (the linear velocity at the innermost circumference of the recording area of the disk is 20-25 m / s). Become. That is, it becomes difficult to initialize the entire disk surface at a high linear velocity of 25 m / s or more because of the limit of the mechanical strength of the polycarbonate resin substrate.

  On the other hand, on the recording device (for example, CD-RW or DVD drive) side for recording / erasing / reproducing an optical information recording medium, a so-called P-CAV (Partial Angular velocity), ZCLV (Zoned CLV) method is used. Thus, rewriting is performed at a higher linear velocity toward the outer peripheral portion. The adoption of such a method means a change in recording (erasing) linear velocity at the radial position of the optical information recording medium. For this reason, the optical information recording medium may be designed so that optimum recording characteristics can be obtained for recording (erasing) linear velocities in different radial directions. However, in an actual optical information recording medium, such a design that intentionally changes the medium characteristics in the radial direction is not performed, and the fastest rewriting linear velocity at the outermost peripheral portion (in practice, 20-25 m). / S), the entire recording area is designed to be rewritable (amorphous marks can be erased). Therefore, when the recording medium is initially crystallized in the manufacturing process of such an optical information recording medium, it is necessary to initialize the entire recording medium while irradiating the laser beam at a high linear velocity.

  Therefore, an initialization method capable of avoiding the problem of the upper limit of the initialization linear velocity in the CLV method, which occurs due to the limit of the number of revolutions of the initialization device, and the manufacturing method of the optical information recording medium, and the initialization device are provided. It has been demanded.

In view of the above situation, the present inventors have found an initialization method for increasing the relative linear velocity between the laser beam for initialization and the recording medium toward the outer peripheral portion, rather than the conventional initialization method with a constant linear velocity. It was. More specifically, the present inventors use a CAV method (Constant Angular Velocity) and a P-CAV method (Partial CAV method) in which the rotation speed is constant over the entire recording area. An initialization method for increasing the linear velocity was found. Further, the present inventors have divided the recording medium into a plurality of zones and made the ZCLV method (Zoned CLV) in which the rotational speed is constant in the innermost peripheral portion of each zone and the linear velocity is constant in each zone. The initialization method was found to increase the linear velocity toward the outer periphery of the recording medium.
Then, it has been found that the use of these initialization methods eliminates the burden on the initialization apparatus and complicated control.

That is, the gist of the present invention is a method for producing an optical information recording medium having a phase change recording layer on a disk-shaped substrate, and a step of obtaining a recording medium on which the recording layer is formed, and focusing An initial crystallization step of initial crystallization of the recording layer by scanning a light spot formed by irradiating the recording layer with light in a circumferential direction of the recording medium, in the initial crystallization step, The scanning linear velocity when scanning the light spot in the circumferential direction is increased toward the outer periphery of the recording medium, and the intensity of the focused light is increased as the scanning linear velocity is increased so that the entire surface of the initial crystallization region is initialized. in the case of reduction, the rotation speed R0 per unit time of the recording medium constant, the manufacturing method of the optical information recording medium and setting the rotation speed R0 so as to satisfy the following conditions To.
(I) A plurality of recording media are prepared, and one of the recording media is rotated at an arbitrary number of revolutions, and at least the recording layer formed on the innermost track of the recording area of the recording medium is initially crystallized. Turn into.
(Ii) Recording is performed twice on the innermost track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) After initial crystallization is performed on another recording medium at a rotational speed different from the rotational speed of (i), the above (ii) to (iv) are performed.
(Vi) The operation of (v) is repeated while changing the recording medium.
(Vii) The relationship between J2 / J10 obtained from the jitter values J2 and J10 obtained with the recording medium initially crystallized at each rotational speed and the rotational speed at the time of initial crystallization is obtained. And R0 is set to the rotation speed which makes J2 / J10 1.6 or less.
Another gist of the present invention is a method for producing an optical information recording medium having a phase change type recording layer on a disk-shaped substrate, the step of obtaining a recording medium having the recording layer formed thereon, An initial crystallization step of initial crystallization of the recording layer by scanning a light spot formed by irradiating the recording layer with focused light in a circumferential direction of the recording medium, and in the initial crystallization step In the case of initial crystallization of the entire surface of the initial crystallization region by increasing the scanning linear velocity at the time of scanning the light spot in the circumferential direction as the outer peripheral portion of the recording medium, the radial direction of the recording medium For optical information recording, wherein the initial crystallization region is divided into a plurality of zones, the intensity of the focused light irradiated in each zone is constant, and the intensity of the focused light is increased toward the outer peripheral side of the recording medium. Medium It resides in the production method.
Another gist of the present invention is a method for producing an optical information recording medium having a phase change type recording layer on a disk-shaped substrate, the step of obtaining a recording medium having the recording layer formed thereon, An initial crystallization step of initial crystallization of the recording layer by scanning a light spot formed by irradiating the recording layer with focused light in a circumferential direction of the recording medium, and in the initial crystallization step The scanning linear velocity when scanning the light spot in the circumferential direction is increased toward the outer periphery of the recording medium, and the intensity of the focused light is increased as the scanning linear velocity is increased to cover the entire surface of the initial crystallization region. In the case of initial crystallization, the initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, the number of rotations at the innermost circumferential position in each zone is constant, There are existing in the production method of the optical information recording medium characterized by a constant the scanning linear velocity from the innermost to the outermost.
Another gist of the present invention is a method for producing an optical information recording medium having a phase change type recording layer on a disk-shaped substrate, the step of obtaining a recording medium having the recording layer formed thereon, An initial crystallization step of initial crystallization of the recording layer by scanning a light spot formed by irradiating the recording layer with focused light in a circumferential direction of the recording medium, and in the initial crystallization step The scanning linear velocity when scanning the light spot in the circumferential direction is increased toward the outer periphery of the recording medium, and the intensity of the focused light is increased as the scanning linear velocity is increased to cover the entire surface of the initial crystallization region. In the case of initial crystallization, the unit per unit time of the recording medium until reaching a predetermined radial position from the innermost peripheral position of the initial crystallization region of the recording medium toward the outer peripheral side of the recording medium. Rotational speed 0 is constant, the scanning linear velocity is constant from the predetermined radial position to the outermost peripheral position of the initial crystallization region, the linear velocity at the predetermined radial position is the maximum linear velocity Vmax, and the maximum A method for manufacturing an optical information recording medium, wherein the linear velocity Vmax is set so as to satisfy the following condition.
(I) A plurality of recording media are prepared, and the recording layer formed on an arbitrary track in the initial crystallization region is initially crystallized at an arbitrary linear velocity with respect to one of the recording media. .
(Ii) Recording is performed twice on the track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) Repeat (i) to (iv) by changing the recording medium and changing the linear velocity.
(Vi) The linear velocity that makes J2 / J10 obtained from the jitter values J2 and J10 obtained at the respective linear velocities 1.6 or less is the maximum linear velocity Vmax.

Another gist of the present invention is an initialization apparatus for initial crystallization of a recording layer of a recording medium having a phase change recording layer on a disk-shaped substrate, wherein focused light is focused on the recording layer. A control unit that scans the light spot formed by irradiation in the circumferential direction of the recording medium, and the control unit increases the linear velocity when scanning the light spot in the circumferential direction as the outer peripheral part of the recording medium; It is configured to increase the intensity of the focused light as the scanning line speed increases and to initially crystallize the entire surface of the initial crystallization region, and the control unit rotates the recording medium per unit time. is configured to R0 to constant consists in initializing apparatus according to claim Rukoto is configured to rotate the recording medium based on the rotation speed R0 which is set so as to satisfy the following conditions.
(I) A plurality of recording media are prepared, and one of the recording media is rotated at an arbitrary number of revolutions, and at least the recording layer formed on the innermost track of the recording area of the recording medium is initially crystallized. Turn into.
(Ii) Recording is performed twice on the innermost track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) After initial crystallization is performed on another recording medium at a rotational speed different from the rotational speed of (i), the above (ii) to (iv) are performed.
(Vi) The operation of (v) is repeated while changing the recording medium.
(Vii) The relationship between J2 / J10 obtained from the jitter values J2 and J10 obtained with the recording medium initially crystallized at each rotational speed and the rotational speed at the time of initial crystallization is obtained. And R0 is set to the rotation speed which makes J2 / J10 1.6 or less.
Another gist of the present invention is an initialization apparatus for initial crystallization of a recording layer of a recording medium having a phase change recording layer on a disk-shaped substrate, wherein focused light is focused on the recording layer. A control unit that scans the light spot formed by irradiation in the circumferential direction of the recording medium, and the control unit increases the linear velocity when scanning the light spot in the circumferential direction as the outer peripheral part of the recording medium. The entire surface of the initial crystallization region is configured to perform initial crystallization, the initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, and the control unit performs irradiation in each zone. The initialization apparatus is characterized in that the intensity of the focused light is constant and the intensity of the focused light is increased in the outer peripheral zone of the recording medium.
Another gist of the present invention is an initialization apparatus for initial crystallization of a recording layer of a recording medium having a phase change recording layer on a disk-shaped substrate, wherein focused light is focused on the recording layer. A control unit that scans the light spot formed by irradiation in the circumferential direction of the recording medium, and the control unit increases the linear velocity when scanning the light spot in the circumferential direction as the outer peripheral part of the recording medium; As the scanning linear velocity increases, the intensity of the focused light is increased so that the entire surface of the initial crystallization region is initially crystallized, and the initial crystallization region extends along the radial direction of the recording medium. It is divided into a plurality of zones, and the control unit is configured so that the number of rotations at the innermost circumference position in each zone is constant, and the scanning linear velocity is constant from the innermost circumference to the outermost circumference in each zone. Be done It consists in initializing apparatus according to claim.
Another gist of the present invention is an initialization apparatus for initial crystallization of a recording layer of a recording medium having a phase change recording layer on a disk-shaped substrate, wherein focused light is focused on the recording layer. A control unit that scans the light spot formed by irradiation in the circumferential direction of the recording medium, and the control unit increases the linear velocity when scanning the light spot in the circumferential direction as the outer peripheral part of the recording medium; As the scanning linear velocity increases, the intensity of the focused light is increased so that the entire surface of the initial crystallization region is initially crystallized, and the control unit controls the initial crystallization region of the recording medium. The rotational speed R0 per unit time of the recording medium is constant until reaching a predetermined radial position from the innermost position toward the outer peripheral side of the recording medium, and the initial crystal is determined from the predetermined radial position. Up to the outermost position of the The scanning linear velocity is constant, the maximum linear velocity Vmax in the predetermined radial position, the initialization unit and setting so as to satisfy the conditions below.
(I) A plurality of recording media are prepared, and the recording layer formed on an arbitrary track in the initial crystallization region is initially crystallized at an arbitrary linear velocity with respect to one of the recording media. .
(Ii) Recording is performed twice on the track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) Repeat (i) to (iv) by changing the recording medium and changing the linear velocity.
(Vi) The linear velocity that makes J2 / J10 obtained from the jitter values J2 and J10 obtained at the respective linear velocities 1.6 or less is the maximum linear velocity Vmax.

  The present invention particularly relates to an optical information recording medium having a phase change type recording material for high-speed recording (for example, a CD-RW for recording at a linear velocity of 24 times or higher, or a linear velocity of 6 to 8 times or higher). When applied to a rewritable DVD for recording, an optical information recording medium having a good initialization state can be obtained.

  According to the present invention, there is an advantage that an optical information recording medium having a good initial crystallization state can be obtained by an initial crystallization method different from the conventional one. That is, initial crystallization can be performed at a high linear velocity (for example, a linear velocity higher than the erasable linear velocity of the optical information recording medium such as about 25 m / s or more). As a result, good recording characteristics can be obtained, and the medium performance can be improved. Furthermore, the initial crystallization time can be greatly shortened, and the productivity of the optical information recording medium can be improved.

  In particular, when an optical information recording medium that is rewritten at a high recording linear velocity is initially crystallized, good recording characteristics can be obtained. In this case, problems such as insufficient mechanical durability of the disk, an increase in the size of the initialization device, and an increase in the cost of the initialization device do not occur.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.
[1] Configuration of optical information recording medium and manufacturing method thereof (step of obtaining a recording medium having a recording layer formed thereon)
Specific examples of a recording medium having a phase change recording layer include a first protective layer (lower protective layer), a recording layer (phase change recording layer), and a second protective layer (upper protection) on a disk-shaped substrate. Layer), a reflective layer, and a protective coating layer in this order, and a recording medium that records and reproduces signals by irradiating laser light through the substrate (after initialization, optical information recording of the substrate surface incidence type) Used as a medium for use).

  Other specific examples of the optical information recording medium having a phase change type recording layer include a reflective layer, a second protective layer (lower protective layer), a recording layer (phase change type) on a disk-shaped substrate. A recording medium having a recording layer), a first protective layer (upper protective layer), and a protective coating layer in this order, and recording and reproducing signals by irradiating laser light through the upper protective layer (after initialization) Used as a film surface incident type optical information recording medium). In this film surface incidence type optical information recording medium, signals are recorded and reproduced by irradiating a laser beam from the upper protective layer side without passing through the substrate. For this reason, the distance between the recording layer and the optical head can be made to approach several hundred microns or less. The recording density of the medium can be improved by using an objective lens having a numerical aperture of 0.7 or more.

  The layer structures of the substrate surface incidence type optical information recording medium and the film surface incidence type optical information recording medium are shown as examples. For example, an interface layer can be provided between the protective layer and the reflective layer in both the substrate surface incident optical information recording medium and the film surface incident optical information recording medium. In the film surface incidence type optical information recording medium, an underlayer may be provided between the substrate and the reflective layer.

In the present invention, it is preferable to use a recording medium in which a recording material having a high crystallization speed and capable of a high data transfer rate is used for the recording layer.
Hereinafter, each layer of the substrate, the recording layer, and other layers (protective layer, reflective layer, protective coat layer) will be described.
(1) Substrate For the substrate, for example, a resin such as polycarbonate, acrylic, polyolefin, or glass can be used. Of these, polycarbonate resin is most preferable because it has a track record of being most widely used in CD-ROMs and the like and is inexpensive. The thickness of the substrate is usually 0.1 mm or more, preferably 0.3 mm or more, while it is usually 20 mm or less, preferably 15 mm or less. Generally, it is set to about 0.6 mm to 1.2 mm. In a substrate surface incident type optical information recording medium, the substrate needs to be transparent to the laser beam because the substrate needs to transmit the laser beam. On the other hand, in a film surface incident type optical information recording medium, the substrate is not necessarily transparent.

A concentric or spiral track (groove) is usually formed on the substrate. In addition, the shape of the substrate is a disk shape, but the “disk shape” here refers to a rotatable shape, usually a planar disk shape, but is not limited to a planar disk shape. For example, in order to make the design of the optical information recording medium attractive, it is needless to say that a planar elliptical shape or a planar rectangular shape may be used.
(2) Recording layer For the recording layer, for example, a series of compounds such as GeSbTe, InSbTe, AgSbTe, and AgInSbTe is selected as a material capable of repeated recording. Among these, a composition mainly composed of a pseudo binary alloy of Sb ₂ Te ₃ and GeTe, more specifically, {(Sb ₂ Te ₃ ) _1-α (GeTe) _α } _1-β Sb _β composition (However, 0.2 ≦ α ≦ 0.9, 0 ≦ β ≦ 0.1) or a composition mainly containing Sb.

  The initialization method used in the present invention (an initialization method in which the scanning linear velocity is increased as the initialization light spot moves toward the outer periphery of the recording medium) is a recording using a material having a high crystallization speed for the recording layer. It is preferable to apply to a medium. In order to increase the crystallization speed, it is more preferable to use a composition containing Sb as a main component in the recording layer. In the present invention, “having Sb as a main component” means that the content of Sb in the entire recording layer is 50 atomic% or more. The reason why Sb is the main component is that the amorphous Sb can be crystallized at a very high speed, so that the amorphous mark can be crystallized in a short time. For this reason, it is easy to erase the recording marks in the amorphous state. In this respect, the Sb content is preferably 60 atomic% or more, and more preferably 70 atomic% or more. However, on the other hand, it is preferable to use an additive element together with Sb in order to promote the formation of the amorphous phase and increase the temporal stability of the amorphous state. In order to promote the amorphous formation of the recording layer and increase the temporal stability of the amorphous state, the content of the additive element is usually 1 atomic% or more, preferably 5 atomic% or more, more preferably 10 atomic% or more, and usually 30 atomic% or less.

  The additive element that promotes amorphous formation and improves the temporal stability of the amorphous state also has the effect of increasing the crystallization temperature. Examples of such additive elements include Ge, Te, In, Ga, Sn, Pb, Si, Ag, Cu, Au, rare earth elements, Ta, Nb, V, Hf, Zr, W, Mo, Cu, Cr, and Co. Nitrogen, oxygen, Se, or the like can be used. Among these additive elements, from the viewpoint of promoting amorphous formation, improving the temporal stability of the amorphous state, and increasing the crystallization temperature, it is preferable to use Ge, Te, In, Ga, and Sn. At least one selected. Particular preference is given to using Ge and / or Te or using at least one of In, Ga and Sn.

  As described above, in the recording layer of the recording medium used in the initialization method, Sb and Sb are used as the recording layer material for high-speed crystallization, formation of an amorphous state, and improvement of the temporal stability of the amorphous state. It is particularly preferable to use Ge and / or Te together. When Ge and / or Te are added to Sb, the content of Ge or Te in the recording layer is preferably set to 1 atom% or more and 30 atom% or less. That is, it is preferable that Ge and Te are contained individually by 1 atomic% or more and 30 atomic% or less. However, when the main component of the recording layer is Sb, the Sb content is 50 atomic% or more. Therefore, when Ge and Te are contained in the recording layer together with Sb, the total amount of Ge and Te is more than 50 atomic%. Will be less.

  Each content of Ge or Te in the recording layer is more preferably 3 atomic% or more, and further preferably 5 atomic% or more. If it is within this range, the effect of stabilizing the amorphous mark is sufficiently exhibited. On the other hand, the content of Ge or Te in the recording layer is more preferably 20 atomic% or less, and further preferably 15 atomic% or less. Within this range, it is possible to suppress the tendency of the amorphous material to become too stable and conversely slow crystallization. Moreover, if it is the said range, the noise by the light scattering in a crystal grain boundary can be suppressed now.

The composition containing Sb as a main component can be classified into two types depending on the amount of Te contained in the recording layer. One is a composition containing 10 atomic percent or more of Te, and the other is a composition containing less than 10 atomic percent of Te (including a case where Te is not contained).
One of them is that the recording layer material contains, as a main component, an alloy containing approximately 10 atomic% or more of Te and containing Sb in excess of the Sb ₇₀ Te ₃₀ eutectic composition. Hereinafter, this recording layer material is referred to as an SbTe eutectic system. Here, Sb / Te is preferably 3 or more, and more preferably 4 or more.

As another composition containing Sb as a main component, which can be classified according to the amount of Te contained in the recording layer, the following can be mentioned. That is, the composition of the recording layer is such that Te is the main component, Te is less than 10 atomic%, and Ge is contained as an essential component. As a specific example of the composition of the recording layer, an alloy containing an eutectic alloy having a composition near Sb ₉₀ Ge ₁₀ as a main component and containing less than 10 atomic% of Te (in this specification, this alloy is referred to as an SbGe eutectic system). Can be preferably mentioned.

  A composition in which the amount of Te added is less than 10 atomic% has properties as an SbGe eutectic system, not an SbTe eutectic system. Even if this SbGe eutectic alloy has a high Ge content of about 10 atomic%, the crystal state of the polycrystalline state after the initial crystallization is relatively fine, so the crystalline state tends to be a single phase, Noise is low. In an SbGe eutectic alloy, Te is only added and does not become an essential element.

In the SbGe eutectic alloy, by increasing the Sb / Ge ratio relatively, the crystallization speed can be increased, and the amorphous mark can be recrystallized by recrystallization.
In the case where the recording layer is made of a composition containing Sb as a main component, the crystal state is set to an unrecorded / erased state, and an amorphous mark is formed to perform recording, it is very important to improve the cooling efficiency. This is due to the following reason.

That is, the SbTe eutectic-based or SbGe eutectic-based recording layer containing Sb as a main component is more suitable than high-speed recording than the vicinity of the Sb ₇₀ Te ₃₀ eutectic point or the Sb ₉₀ Ge ₁₀ eutectic point. Furthermore, Sb is added excessively to increase the crystal growth rate, not the crystal nucleation rate, thereby increasing the crystallization rate. For this reason, in these recording layers, it is preferable to increase the cooling rate of the recording layer to suppress changes in the amorphous mark due to recrystallization (the amorphous mark becomes smaller than a desired size). . Therefore, it is important to rapidly cool the recording layer in order to reliably form the amorphous mark after melting the recording layer, and it is very important to improve the cooling efficiency of the recording layer. Therefore, in the recording layer composition, it is particularly preferable to use Ag or an Ag alloy having high heat dissipation for the reflective layer. The use of the initialization method of the present invention is significant for a recording medium having a recording layer that needs to increase the cooling efficiency during recording.

In the recording layer using a composition containing Sb as a main component, such as SbTe eutectic or SbGe eutectic, the recording layer further contains at least one of In, Ga, and Sn. It is particularly preferable that the respective contents of Sn and Sn are 1 atomic% or more and 30 atomic% or less.
Hereinafter, specific examples of the composition containing Sb as a main component will be further described.

As a composition containing Sb as a main component, first, (Sb _x Te _1-x ) _{1- y My} (where 0.6 ≦ x ≦ 0.9, 0 ≦ y ≦ 0.3, M is Ge, Ag, In, Ga, Zn, Sn, Si, Cu, Au, Pd, Pt, Pb, Cr, Co, O, S, Se, V, Nb, and Ta)) an alloy as a main component Preferred examples include SbTe eutectic compositions. In addition, the said composition formula represents a composition by atomic ratio. Therefore, for example, x = 0.6 means 60 atomic%.

In the above _{(Sb x Te 1-x)} 1-y M y composition, as the M, Ge, Ga, be used Ag or In alone or in combination, particularly in view of recording characteristics such as overwriting characteristics preferable.
In the above _{(Sb x Te 1-x)} 1-y M y composition, x is usually 0.6 or more, preferably 0.7 or more, more preferably 0.75 or more, whereas, typically 0.9 The following. In addition, y is usually 0 or more, preferably 0.01 or more, more preferably 0.03 or more, and usually 0.3 or less, preferably 0.2 or less, more preferably 0.1 or less. . When x and y are within the above ranges, a recording layer that can support high-speed recording can be obtained.

Further described composition using the Ge as M in the above _{(Sb x Te 1-x)} 1-y M y composition. As this composition, Ge _y (Sb _x Te _1-x ) _{1-y based} on an Sb ₇₀ Te ₃₀ alloy containing a large excess of Sb based on the Sb ₇₀ Te ₃₀ eutectic point composition and further containing Ge. (However, it is preferable to use a composition represented by 0.01 ≦ y ≦ 0.06, 0.7 ≦ x ≦ 0.9). The Ge amount is preferably 0.01 or more, particularly preferably 0.02 or more, as the value of _y in Ge _y (Sb _x Te _1-x ) _1-y . On the other hand, in the SbTe eutectic composition having a large Sb content, when the Ge amount is too large, GeTe and GeSbTe-based intermetallic compounds are precipitated, and an SbGe alloy can be precipitated. It is estimated that crystal grains with different constants coexist. The mixing of crystal grains may increase the noise of the recording layer and increase the jitter. Even if Ge is added too much, the effect of the stability of amorphous marks over time is saturated. For this reason, the content of Ge is usually 0.06 or less, preferably 0.05 or less, more preferably 0.04 or less as the value of _y in Ge _y (Sb _x Te _1-x ) _{1 -y} . .

In the GeSbTe eutectic composition, it is particularly preferable to further contain In, Ga, and Sn. That is, M1 _z Ge _y (Sb _x Te _1-x ) _1-yz (0.01 ≦ z ≦ 0.4, 0.01 ≦ y ≦ 0.06, 0.7 ≦ x ≦ 0.9, It is particularly preferable to use a composition represented by the following formula: M1 represents at least one element selected from the group consisting of In, Ga, and Sn. When M1 is at least one of a group of elements represented by In, Ga, and Sn, the characteristics are further improved. In, Ga, and Sn elements can increase the optical contrast between the crystalline state and the amorphous state, and also have the effect of reducing jitter. Z indicating the content of M1 is usually 0.01 or more, preferably 0.02 or more, more preferably 0.05 or more, and usually 0.15 or less, preferably 0.1 or less. If it is in this range, the effect of improving the characteristics will be exhibited well.

Above, In, in a GeSbTe alloy containing Sn, as another preferred composition range may include _{Ge x (In w Sn 1-} w) y Te z Sb 1-xyz. Here, the Sb content is higher than any of the Ge content, the In content, the Sn content, and the Te content. Satisfy (i) to (vi).
(I) 0 ≦ x ≦ 0.3
(Ii) 0.07 ≦ yz
(Iii) w × y−z ≦ 0.1
(Iv) 0 <z
(V) (1-w) × y ≦ 0.35
(Vi) 0.35 ≦ 1-xyz
With the above recording layer composition, it is possible to satisfactorily overwrite at a linear velocity of 20 m / s or more. Hereinafter, the relationship between the content of each element and the characteristics in the recording layer composition will be described in detail.
(Sb, formula (vi))
The Sb content is higher than any of the Ge content, the In content, the Sn content, and the Te content. That is, the recording material of the present invention is mainly composed of Sb. Specifically, the Sb content is 35 atomic% or more, which is higher than any of the other contained elements. In order to sufficiently obtain the effects of the present invention, the Sb content is preferably 40 atomic% or more, and more preferably 45 atomic% or more.
(Sn, formula (ii), (v))
The influence of Sn content on the reflectivity in the crystalline state and the difference in reflectance between the crystal and the amorphous phase (signal amplitude), and the In content on the reflectance in the crystalline state and the difference in reflectance between the crystalline and amorphous phase (signal amplitude) ) Has almost the same effect. For this reason, the recording layer composition contains either Sn or In. And the reflectance of a crystal | crystallization and a signal amplitude can be enlarged by making the sum total of Sn content and In content within the range of fixed amount from Te amount. On the other hand, when the Te content increases, the reflectance and signal amplitude of the crystal decrease. Therefore, in order to obtain a desired crystal state reflectance and signal amplitude, it is important to control the relationship between the Sn and / or In content and the Te content.

For this reason, the value of (yz) in the above general formula is 0.07 or more, preferably 0.1 or more, more preferably 0.13 or more, and particularly preferably 0.15 or more. A larger value of y is preferable because the optimum power decreases.
Further, since jitter characteristics tend to deteriorate when Sn is too much, the value of (1-w) × y in the above general formula is 0.35 or less, preferably 0.3 or less. Therefore, when a large amount of Te is contained, it is necessary to increase the sum of the In content and the Sn content from the viewpoint of controlling the signal amplitude. On the other hand, considering the jitter characteristics, Sn cannot be increased so much, and when increasing the Te content, it is preferable to include In in addition to Sn. Specifically, in the case where the Te content is increased so that the decrease in reflectance and signal amplitude due to Te cannot be suppressed unless Sn is contained in excess of 35 atomic%, In may be included. .
(In, formula (iii))
By using In, the reflectance in the crystalline state and the difference in reflectance (signal amplitude) between the crystal and the amorphous can be increased. For this reason, it is preferable to use In as an element to be contained in the recording layer.

  By using In, it is possible to increase the reflectance in the crystalline state and the difference in reflectance between the crystal and the amorphous state (signal amplitude) and to reduce the influence on the jitter characteristics compared to Sn. From Sn and Te, it is presumed that there is a function to reduce crystal grain boundary noise. On the other hand, In causes a decrease in reflectance due to long-term storage, which seems to be derived from a metastable crystalline state. In contrast, Te tends to suppress a decrease in reflectance due to long-term storage. Therefore, it is important that the In content and the Te content have a predetermined relationship from the viewpoint of suppressing a decrease in reflectance of the optical information recording medium during long-term storage. That is, in the above general formula, by setting the value of (In content−Te content) within a predetermined range, it is possible to suppress a decrease in reflectance due to long-term storage. Specifically, if the value of w × yz in the above general formula is small, the rate of decrease in reflectance due to long-term storage is small, so the value of w × yz is preferably 0.1 or less, 0.05 The following is more preferable, and it is more preferable to set it to 0 or less. Here, w × yz = 0 means that the In content and the Te content are the same. Therefore, it is more preferable in the present invention that the In content is the same as the Te content or the In content is smaller than the Te content.

  Thus, if it is attempted to reduce the reflectivity decrease due to long-term storage as much as possible, In cannot be contained excessively with respect to Te. Therefore, in order to satisfy the above-described relational expression 0.07 ≦ yz, The recording layer composition preferably contains Sn in addition to In. Specifically, when w × yz <0.07, 0.07 ≦ y−z cannot be satisfied unless Sn is contained in addition to In. In addition, it is preferable to contain both In and Sn from the viewpoint that increasing the contents of In and Te without containing Sn makes it difficult to obtain a crystallization speed suitable for high-speed recording. That is, 0 <w <1 is preferable.

When In is excessively large, the signal quality in the long-term storage of the optical information recording medium tends to deteriorate. Further, when In is increased without containing Sn, a stable crystal layer with a low reflectance, which is seen in the In—Sb system, may appear. For this reason, the In content, that is, the value of w × y is preferably set to 0.35 or less.
(Te, formula (iv))
Te is contained in the recording layer composition. Te can improve the durability of repeated recording. For this reason, the Te content is preferably increased to some extent, but as described above, the relationship between In and / or Sn and Te and the relationship between In and Te must be controlled within a predetermined range. Specifically, z indicating the content of Te in the above general formula is 0 <z, preferably 0.01 ≦ z, more preferably 0.05 ≦ z, and still more preferably 0.08 ≦ z. Particularly preferably, 0.1 ≦ z, and most preferably 0.1 <z.

Although z representing Te content is usually less than 0.29, this is a value inevitably determined by other relational expressions defined in the above general formula. As described above, it is preferable to increase the content of In and Te to some extent, but Te in particular serves to slow the crystallization rate. Therefore, in order to obtain a crystallization speed suitable for high-speed recording, z representing Te content is preferably 0.25 or less, and more preferably 0.20 or less.
(Ge, formula (i))
Ge can be used to adjust the crystallization rate. That is, Ge is not greatly related to characteristics such as reflectivity, signal amplitude (reflectance difference between crystal and amorphous), and reflectivity decrease due to long-term storage of the medium. For this reason, Ge can be used to obtain a crystallization rate suitable for the recording conditions to be used. Since the crystallization speed decreases as the Ge content increases, the crystallization speed can be adjusted by reducing the Ge content in an optical information recording medium for higher speed recording, for example. However, the crystallization speed is related to the content of other elements, and the crystallization speed increases as Sn increases, and the crystallization speed decreases as In and Te increase. Therefore, it is preferable to adjust the crystallization speed according to the recording conditions by adjusting the Ge content after determining the content ratio of elements other than Ge in consideration of the above-mentioned characteristics. If the Ge content is too high, the crystallization rate becomes too slow, so x in the above general formula is 0.3 or less, preferably 0.25 or less, more preferably 0.2 or less. The influence of the content on the crystallization rate is particularly large for Ge and Te.

  Further, when the Ge content is high, when the recorded amorphous mark is stored for a long period of time, the amorphous mark tends to be harder to crystallize than immediately after recording before storage. When this phenomenon becomes significant, the signal quality of the overwritten recording signal becomes insufficient when overwriting is performed after the recorded optical information recording medium is stored for a long period of time. That is, the old mark after long-term storage does not disappear sufficiently, so that the signal quality of the new recording mark is deteriorated. This phenomenon of difficulty in crystallization becomes a problem only in the first recording after long-term storage, and an amorphous mark newly recorded after long-term storage has a normal crystallization speed. In any case, this phenomenon is alleviated by reducing the Ge content. In this sense, the Ge content is preferably small, and the value of x in the above general formula is particularly preferably 0.1 or less, and most preferably 0.07 or less.

  As described above, Te and In have the effect of slowing down the crystallization speed. Therefore, in order to obtain the same crystallization speed when the crystallization speed is slowed down, the content of Te and In is higher when the content of Te and In is higher. Can be reduced. In this sense, the Te content, that is, the value of z is preferably 0.05 or more, more preferably 0.08 or more, and most preferably 0.1 or more. Further, at this time, the In content, that is, the value of w × y is preferably 0.05 or more, and more preferably 0.08 or more. Moreover, when there is much Te content as mentioned above, it becomes preferable to contain both In and Sn. That is, the most preferable composition contains all of Ge, In, Sb, Sn, and Te.

  On the other hand, if the Ge content is too small, the storage stability of the amorphous mark is deteriorated and tends to crystallize by long-term storage. The storage stability of the amorphous mark tends to be improved by increasing In, but the influence of Ge tends to be stronger. On the other hand, due to the influence of other elements, the storage stability of amorphous marks may be relatively good even when the Ge content is zero. Therefore, the value of x in the above general formula is 0 or more, but is preferably larger than 0, more preferably 0.01 or more, and further preferably 0.02 or more.

In the GeSbTe eutectic composition, elements other than In, Ga, and Sn can include nitrogen, oxygen, and sulfur. These elements are effective in preventing segregation in repeated overwriting and fine adjustment of optical characteristics. The content of nitrogen, oxygen and sulfur is more preferably 5 atomic% or less with respect to the total amount of Sb, Te and Ge.
Further, Cu, Zr, Hf, V, Nb, Ta, Cr, and Co can be contained in the GeSbTe eutectic composition. These elements, when added in a very small amount, are effective in raising the crystallization temperature without lowering the crystal growth rate and further improving the stability over time. However, if the amount of these elements is too large, segregation of a specific substance over time or segregation due to repeated overwriting tends to occur, so the addition amount is preferably 5 atomic% or less, particularly preferably 3 atomic% or less. When segregation occurs, the amorphous characteristics of the recording layer, the recrystallization speed, and the like may change, and the overwrite characteristics may deteriorate.

  On the other hand, as the SbGe eutectic composition, which is a composition containing Sb as a main component, a composition containing TeGeSb as a main component, in which Te is added to the SbGe eutectic system, and In, Ga, or Sn is added to the SbGe eutectic system. , InGeSb-based, GaGeSb-based, or SnGeSb-based ternary alloys. By adding Te, In, Ga, or Sn to an SbGe eutectic alloy, the effect of increasing the optical characteristic difference between the crystalline state and the amorphous state can be made remarkable. It is preferable to add.

Preferred compositions of such SbGe eutectic _{alloy, TeγM2δ (GeεSb 1- ε) 1-} δ - γ ( although, 0.01 ≦ ε ≦ 0.3,0 ≦ δ ≦ 0.3,0 ≦ γ <0.1, 2 ≦ δ / γ, 0 <δ + γ ≦ 0.4, and M2 is one selected from the group consisting of In, Ga, and Sn. By adding In, Ga, or Sn to the SbGe eutectic alloy, the effect of increasing the optical characteristic difference between the crystalline state and the amorphous state can be made remarkable.

  By using In and Ga as the element M2, jitter in ultrahigh-speed recording can be improved and the optical contrast can be increased. For this reason, δ indicating the content of In and / or Ga is usually 0 or more, preferably 0.01 or more, more preferably 0.05 or more. However, if In or Ga is excessively large, in addition to the crystal phase used as the erased state, an extremely low reflectance In—Sb-based or other crystal phase of Ga-Sb may be formed. . Therefore, δ is usually 0.3 or less, preferably 0.2 or less. Note that when In and Ga are compared, In can achieve lower jitter, and therefore M2 is preferably In.

  On the other hand, by using Sn as the element M2, jitter in ultrahigh-speed recording is improved, and optical contrast (difference in reflectance between the crystalline state and the amorphous state) can be increased. For this reason, δ indicating the Sn content is usually 0 or more, preferably 0.01 or more, more preferably 0.05 or more. However, if Sn is excessively large, the amorphous phase immediately after recording may change to another amorphous phase with low reflectivity. In particular, when stored for a long time, this stabilized amorphous phase tends to precipitate and the erasing performance tends to deteriorate. Therefore, δ is usually 0.3 or less, preferably 0.2 or less.

A plurality of elements of In, Ga, and Sn can be used as the element M2, but it is particularly preferable to contain In and Sn. When In and Sn are contained, the total content of these elements is usually 1 atomic% or more, preferably 5 atomic% or more, and usually 40 atomic% or less, preferably 30 atomic% or less, more preferably 25 atomic% or less. And
In the TeM2GeSb-based composition, it is possible to improve the change over time in the erase ratio in the ultra-high speed recording by containing Te. For this reason, γ indicating the Te content is usually 0 or more, preferably 0.01 or more, and particularly preferably 0.05 or more. However, if Te is excessively large, noise may increase, so γ is usually smaller than 0.1.

  When the TeM2GeSb composition contains Te and the element M2, it is effective to control the total content thereof. Accordingly, δ + γ indicating the content of Te and the element M2 is usually larger than 0, but is preferably 0.01 or more, more preferably 0.05 or more. By making δ + γ within the above range, the effect of simultaneously containing Te and the element M2 can be satisfactorily exhibited. On the other hand, δ + γ is usually 0.4 or less, preferably 0.35 or less, and more preferably 0.3 or less, in order to satisfactorily exhibit the effect of using a GeSb-based eutectic alloy as a main component. On the other hand, δ / γ representing the atomic ratio between the elements M2 and Te is preferably 2 or more. Since the optical contrast tends to be reduced by containing Te, when Te is contained, it is preferable to slightly increase the content of element M2 (slightly increase δ).

Elements that can be added to the TeM2GeSb composition include Au, Ag, Pd, Pt, Si, Pb, Bi, Ta, Nb, V, Mo, rare earth elements, N, O, and the like. It is used for fine adjustment of speed, etc., but the addition amount is about 10 atom% at maximum.
One of the most preferred composition above is _{based, In p Sn q Te r Ge} s Sb t (0 ≦ p ≦ 0.3,0 ≦ q ≦ 0.3,0 <p + q ≦ 0.3,0 ≦ r <0 0.1, 0 <s ≦ 0.2, 0.5 ≦ t ≦ 0.9, p + q + r + s + t = 1). When Te and In and / or Sn are used in combination, it is preferable that (p + q) / r ≧ 2.

The thickness of the recording layer is preferably 5 nm or more in order to obtain a sufficient optical contrast, increase the crystallization speed, and achieve recording erasure in a short time. Further, in order to sufficiently increase the reflectance, the thickness is more preferably 10 nm or more.
On the other hand, the thickness of the recording layer is preferably 100 nm or less, more preferably 50 nm or less, in order to prevent cracking and to obtain a sufficient optical contrast. This is to reduce the heat capacity and increase the recording sensitivity. Moreover, if it is set as the said range, the volume change accompanying a phase change can be made small. For this reason, it is possible to reduce the influence of repeated volume changes due to repeated overwriting on the upper and lower protective layers. As a result, accumulation of irreversible microscopic deformation is suppressed, noise is reduced, and repeated overwrite durability is improved.

In a high-density recording medium such as a rewritable DVD, since the requirements for noise are more severe, the recording layer thickness is more preferably 30 nm or less.
The recording layer can usually be obtained by DC or RF sputtering of a predetermined alloy target in an inert gas, particularly Ar gas.
The density of the recording layer is usually 80% or more, preferably 90% or more of the bulk density. As the bulk density ρ herein, an approximate value according to the following equation (1) is usually used, but it can also be measured by creating a lump of alloy composition constituting the recording layer.

ρ = Σm _i ρ _i (1)
(Here, m _i is the molar concentration of each element i, and m _i ρ _i is the atomic weight of element i.)
In the sputtering film forming method, the pressure of the sputtering gas during film formation (usually a rare gas such as Ar, which will be described below using Ar as an example) is reduced, or the substrate is placed close to the front of the target. For example, the density of the recording layer can be increased by increasing the amount of high energy Ar irradiated to the recording layer. The high energy Ar is usually one in which Ar ions irradiated to the target for sputtering are partially rebounded and reach the substrate side, or Ar ions in the plasma are accelerated by the sheath voltage across the substrate and reach the substrate. Either.

  The irradiation effect of such a high energy rare gas is referred to as an atomic peening effect. In the sputtering using Ar gas that is generally used, Ar is mixed into the sputtered film due to the atomic peening effect. The atomic peening effect can be estimated by the amount of Ar in the film. That is, if the amount of Ar is small, it means that the effect of high energy Ar irradiation is small, and a film with a low density is likely to be formed.

On the other hand, if the amount of Ar is large, the irradiation of high energy Ar becomes intense and the density of the film increases, but Ar taken in the film precipitates as void during repeated overwriting and deteriorates the durability of repeated. Easy to make. Therefore, the discharge is performed at an appropriate pressure, usually in the order of 10 ⁻² to 10 ⁻¹ Pa.
(3) Other layers (protective layer)
In order to prevent evaporation / deformation accompanying the phase change of the recording layer and to control thermal diffusion at that time, a protective layer is usually formed on one or both of the recording layer, preferably both. The material of the protective layer is determined in consideration of the refractive index, thermal conductivity, chemical stability, mechanical strength, adhesion, and the like. In general, a metal having high transparency and a high melting point, or a dielectric such as oxide, sulfide, nitride, carbide, fluoride of Ca, Mg, Li or the like can be used.

In this case, these oxides, sulfides, nitrides, carbides, and fluorides do not necessarily have to have a stoichiometric composition, and the composition may be controlled or mixed for controlling the refractive index and the like. Is also effective. In consideration of repetitive recording characteristics, a mixture of dielectrics is preferable. More specifically, a mixture of a chalcogen compound such as ZnS or rare earth sulfide and a heat-resistant compound such as oxide, nitride, carbide, or fluoride can be used. For example, a mixture of a heat-resistant compound mainly composed of ZnS and a mixture of a heat-resistant compound mainly composed of a rare earth sulfate, particularly Y ₂ O ₂ S, are examples of a preferable protective layer composition.

  As a material for the protective layer, a dielectric material can be generally used. Examples of the dielectric material include oxides such as Sc, Y, Ce, La, Ti, Zr, Hf, V, Nb, Ta, Zn, Al, Cr, In, Si, Ge, Sn, Sb, and Te. , Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Zn, B, Al, Ga, In, Si, Ge, Sn, Sb and nitrides such as Pb, Ti, Zr, Hf, Examples thereof include carbides such as V, Nb, Ta, Cr, Mo, W, Zn, B, Al, Ga, In, and Si, or a mixture thereof. Further, as dielectric materials, sulfides such as Zn, Y, Cd, Ga, In, Si, Ge, Sn, Pb, Sb, and Bi, selenides or tellurides, fluorides such as Mg, Ca, and Li Or mixtures thereof.

Furthermore, specific examples of the dielectric material include ZnS—SiO ₂ , SiN, SiO ₂ , TiO ₂ , CrN, TaS ₂ , Y ₂ O ₂ S and the like. Among these materials, ZnS—SiO ₂ is widely used because of its high film formation rate, low film stress, low volume change rate due to temperature change, and excellent weather resistance. When using a ZnS-SiO _2, ZnS and the composition ratio of SiO ₂ ZnS: SiO ₂ is generally 0: 1 to 1: 0, preferably from 0.5: 0.5 to 0.95: 0.05, more Preferably, the ratio is 0.7: 0.3 to 0.9: 0.1. Most preferably, ZnS: SiO _{2 is set} to 0.8: 0.2.

More specifically, a composite dielectric containing 50 to 90 mol% of rare earth sulfides and sulfates such as La, Ce, Nd, and Y, and a composite dielectric containing 70 to 90 mol% of ZnS and TaS _2. The body is desirable.
Considering repeated recording characteristics, it is desirable from the viewpoint of mechanical strength that the film density of the protective layer is 80% or more of the bulk state. When a dielectric mixture is used, the theoretical density of the above general formula (1) is used as the bulk density.

  The thickness of the protective layer is generally 1 nm or more and 500 nm or less. By setting the thickness to 1 nm or more, the effect of preventing deformation of the substrate and the recording layer can be sufficiently secured, and the role as a protective layer can be sufficiently achieved. In addition, if the thickness is 500 nm or less, it can prevent the occurrence of cracks due to the significant internal stress of the protective layer itself and the difference in elastic properties from the substrate, while sufficiently serving as the protective layer. it can.

  In particular, when the first protective layer positioned on the light incident side as viewed from the recording layer is provided, the first protective layer is required to suppress substrate deformation due to heat, and thus the thickness is usually 1 nm or more, preferably 5 nm. Above, more preferably 10 nm or more, further preferably 20 nm or more, particularly preferably 40 nm or more. In this way, accumulation of microscopic substrate deformation during repetitive recording is suppressed, and reproduction noise is not scattered and noise rises significantly.

  On the other hand, the thickness of the first protective layer is usually 400 nm or less, preferably 300 nm or less, more preferably 200 nm or less, still more preferably 150 nm or less, and particularly preferably 100 nm or less because of the time required for film formation. In this way, the groove shape of the substrate as viewed in the plane of the recording layer is not changed. That is, the phenomenon that the depth and width of the groove become smaller than the intended shape on the substrate surface is less likely to occur.

  On the other hand, when a second protective layer located on the side opposite to the light incident side as viewed from the recording layer is provided, the thickness of the second protective layer is usually 1 nm or more, preferably 5 nm, in order to suppress deformation of the recording layer. Above, more preferably 10 nm or more, still more preferably 15 nm or more. Further, in order to prevent microscopic plastic deformation accumulation inside the upper protective layer, which occurs with repeated recording, and to suppress noise increase due to scattering of reproduction light, the thickness of the second protective layer is preferably 200 nm. In the following, it is more preferably 150 nm or less, more preferably 100 nm or less, further preferably 60 nm or less, particularly preferably 50 nm or less, and most preferably 30 nm or less.

Note that the thickness of the recording layer and the protective layer is not limited from the viewpoint of mechanical strength and reliability, but also takes into account the interference effect associated with the multilayer structure, so that the absorption efficiency of the laser beam is good and the amplitude of the recording signal is high. It is selected so as to increase (that is, it is selected so that the contrast between the recorded state and the unrecorded state is increased).
The protective layer is usually formed by a sputtering method, but it is preferable that the total impurity amount is less than 2 atomic% including the impurity amount of the target itself and the amount of moisture and oxygen mixed during film formation. Therefore, when the protective layer is formed by sputtering, it is desirable that the ultimate vacuum in the process chamber is less than 1 × 10 ⁻³ Pa.
(Reflective layer)
In the optical information recording medium, a reflective layer can be further provided. The position where the reflective layer is provided usually depends on the incident direction of the reproduction light, and is provided on the opposite side of the recording layer with respect to the incident side. That is, when reproducing light is incident from the substrate side, it is usual to provide a reflective layer on the opposite side of the recording layer with respect to the substrate. When reproducing light is incident from the recording layer side, the recording layer and the substrate It is usual to provide a reflective layer between them.

  The material used for the reflective layer is preferably a substance having a high reflectance, and in particular, a metal such as Au, Ag, or Al, which can be expected to have a heat dissipation effect. Although the heat dissipation is determined by the film thickness and the thermal conductivity, the thermal conductivity of these metals is almost proportional to the volume resistivity, so that the heat dissipation performance can be expressed by the area resistivity. The sheet resistivity is usually 0.05Ω / □ or more, preferably 0.1Ω / □ or more, and usually 0.6Ω / □ or less, preferably 0.5Ω / □ or less.

  This guarantees that the heat dissipation is particularly high, and when the competition between amorphization and recrystallization is significant in the formation of an amorphous mark, as in the composition used for the recording layer, re-generation is possible. This is necessary for suppressing crystallization to some extent. A small amount of Ta, Ti, Cr, Mo, Mg, V, Nb, Zr, Si, or the like may be added to the above metal in order to control the thermal conductivity of the reflective layer itself or improve the corrosion resistance. The addition amount is usually 0.01 atomic percent or more and 20 atomic percent or less.

  More specifically, the reflective layer material suitable for the present invention is selected from the group consisting of Ta, Ti, Co, Cr, Si, Sc, Hf, Pd, Pt, Mg, Zr, Mo and Mn. In addition, an Al alloy containing at least one element can be given. Since these alloys have improved hillock resistance, they can be used in consideration of durability, volume resistivity, film formation rate, and the like. The content of the above elements is usually 0.1 atomic% or more, preferably 0.2 atomic% or more, and usually 2 atomic% or less, preferably 1 atomic% or less. Regarding the Al alloy, if the amount of added impurities is too small, the hillock resistance is often insufficient, although it depends on the film forming conditions. Further, if the amount of added impurities is too large, it is difficult to obtain a sufficient heat dissipation effect.

As a specific example of the aluminum alloy, an aluminum alloy containing at least one of Ta and Ti at 15 atomic% or less is excellent in corrosion resistance. For this reason, this Al alloy is a particularly preferable reflective layer material for improving the reliability of the optical information recording medium.
Preferred examples of the reflective layer material include pure Ag or Ag, Ti, V, Ta, Nb, W, Co, Cr, Si, Ge, Sn, Sc, Hf, Pd, Rh, Au, Pt, Mg, Zr, An Ag alloy containing at least one element selected from the group consisting of Mo, Cu, Zn, Mn, and rare earth elements can be given. When importance is attached to stability over time, the additive component is preferably Ti, Mg, or Pd. The content of the above elements is usually 0.01 atomic% or more, preferably 0.2 atomic% or more, and usually 10 atomic% or less, preferably 5 atomic% or less.

In particular, an Ag alloy containing any one of Mg, Ti, Au, Cu, Pd, Pt, Zn, Cr, Si, Ge, and rare earth elements in an amount of 0.01 atomic% to 10 atomic% in Ag has a reflectance, heat, It is preferable because of its high conductivity and excellent heat resistance.
In particular, when the film thickness of the upper protective layer is 40 nm or more and 50 nm or less, it is preferable that the contained additive element is 2 atomic% or less in order to make the reflective layer have high thermal conductivity.

  Particularly preferred as the material of the reflective layer is that Ag is the main component, and most preferred is pure Ag. The reason why Ag is the main component is as follows. That is, when the recording mark stored for a long time is recorded again, there may be a phenomenon that the recrystallization speed of the phase change recording layer is increased only for the first recording immediately after the storage. The reason why such a phenomenon occurs is unknown, but due to the increase in the recrystallization speed of the recording layer immediately after the storage, the size of the amorphous mark formed in the first recording immediately after the storage is desired. It is presumed that it will be smaller than the size of the mark. Therefore, when such a phenomenon occurs, the recording layer is re-recorded during the first recording immediately after storage by increasing the cooling rate of the recording layer using Ag having a very high heat dissipation property for the reflective layer. Crystallization is suppressed, and the size of the amorphous mark can be maintained at a desired size.

  The thickness of the reflective layer is usually 10 nm or more in order to completely reflect incident light without transmitted light, but is preferably 20 nm or more, more preferably 40 nm or more, and more preferably 50 nm or more. Is more preferable. Moreover, even if it is too thick, there is no change in the heat dissipation effect and the productivity is deteriorated unnecessarily, and cracks are likely to occur. Therefore, the thickness of the reflective layer is usually 500 nm or less, but 400 nm or less. It is preferable to set it to 300 nm or less, more preferably 200 nm or less.

The reflective layer is usually formed by sputtering or vacuum deposition. The reflective layer preferably has a total impurity amount of less than 2 atomic%, including the amount of impurities in the target and the evaporation material itself, and the amount of moisture and oxygen mixed during film formation. For this reason, when the reflective layer is formed by sputtering, the ultimate vacuum in the process chamber is preferably less than 1 × 10 ³ Pa.
Further, if the film is formed at an ultimate vacuum lower than 10 ⁴ Pa, it is desirable to prevent the incorporation of impurities by setting the film formation rate to 1 nm / second or more, preferably 10 nm / second or more. Alternatively, when the intentional additive element is included in an amount of more than 1 atomic%, it is desirable to prevent the addition of additional impurities as much as possible by setting the film formation rate to 10 nm / second or more.

  In order to obtain higher heat conduction and higher reliability, it is also effective to make the reflective layer multilayer. In this case, at least one layer is preferably made of the above material having a thickness of 50% or more of the total reflection layer thickness. This layer substantially controls the heat dissipation effect, and the other layers are configured to contribute to the improvement of corrosion resistance, adhesion to the protective layer, and hillock resistance. In particular, when a reflective layer containing pure Ag or Ag as a main component is provided in contact with a protective layer containing ZnS or the like containing sulfur, it usually does not contain sulfur in order to prevent corrosion due to reaction of Ag with sulfur. An interface layer is provided. In this case, the interface layer is preferably a metal that functions as a reflective layer. Examples of the material for the interface layer include Ta and Nb.

Each layer is formed with an in-line device in which the target for the recording layer, the target for the protective layer, and, if necessary, the target for the reflective layer material are installed in the same vacuum chamber, to prevent oxidation and contamination between the layers. Is desirable. It is also excellent in terms of productivity.
(Protective coat layer)
On the outermost surface side of the optical information recording medium, it is preferable to provide a protective coating layer made of an ultraviolet curable resin or a thermosetting resin in order to prevent direct contact with air or damage due to contact with foreign matter. . The protective coat layer is usually 1 μm to several hundred μm thick. Further, a dielectric protective layer having high hardness can be further provided, and a resin layer can be further provided thereon.
(Other)
In this example, a single-layer structure such as a CD-RW has been described as an example. However, the present invention is not limited to this, and other structures (for example, a two-layer structure or a multilayer structure with more layers) The present invention can also be applied to a single-sided incident type or a double-sided incident type having a two-layer structure.

  In general, a recording medium has a recording area where data is actually recorded / reproduced, and the recording area is provided with irregularities for guiding a recording / reproducing light beam. Function as. For example, in a CD / DVD, the recording area is from the inner radius of about 23 mm to the outer radius of about 58 mm. In the recording medium, a thin film having the above-described layer structure is formed on the entire recording area and an area slightly outside the recording area (this may be referred to as a film forming area).

Initialization is usually performed on the entire surface of the film formation region or on the entire surface excluding the edge thereof. If the area where the initialization operation is performed is referred to as an initial crystallization area (initialization area), there is usually a relationship of film formation area ≧ initial crystallization area ≧ recording area.
[2] Initial crystallization step in manufacturing method of optical information recording medium [A] Significance of initial crystallization step The recording layer is usually formed by physical vapor deposition in vacuum such as sputtering. In the state immediately after film formation (as-deposited state), the recording layer is usually amorphous. For this reason, the recording layer needs to be crystallized to be in an unrecorded erased state. This process is called an initialization process (or initial crystallization process, initial crystallization operation).

In the initial crystallization operation, a focused energy beam (especially light energy) is locally irradiated for a very short time at a temperature higher than the crystallization temperature (usually 150 to 300 ° C.) so that the recording layer is not physically destroyed. This is achieved by raising the temperature for a very short time (hereinafter, this initialization method may be referred to as “bulk erase”).
In particular, in the case of a recording medium using a phase change recording material with little crystal nucleation for the recording layer, use of melt initialization that raises the temperature above the melting point of the recording layer in a short time in the above initial crystallization operation. Is particularly preferred. This is because the phase change recording material with little crystal nucleation has a long time for crystallization in the solid phase, resulting in poor production efficiency, and thermal damage to the film formation region due to a long temperature increase. The reason is that there are cases.

  In the melt initialization, if the rate of crystallization is too slow, another crystal phase may be formed because there is a time margin for achieving thermal equilibrium. For this reason, it is preferable to increase the cooling rate to some extent. Also, it is not preferable to hold in a molten state for a long time because the recording layer may flow, the thin film such as the protective layer may be peeled off by stress, or the resin substrate may be deformed, leading to destruction of the recording medium. .

For example, the time for maintaining the melting point or more is usually 10 μs or less, preferably 1 μs or less.
As the energy beam light source of the focused light, a laser beam is preferable because a short-time pulse irradiation operation and a high energy density can be obtained simultaneously. Various laser light sources such as a semiconductor laser and a gas laser can be used. The power of the laser beam is usually about 100 mW to 10 W. It should be noted that other condensing light sources may be used as long as the same power density and focused light shape can be obtained. Specific examples include Xe lamp light. The shape of the focused light focused on the recording layer surface on the focused surface is referred to as a spot, a light spot, a spot shape, or a light spot shape.

The light spot shape of the focused light is particularly preferably an elliptical shape having a minor axis substantially parallel to the scanning direction. Hereinafter, focused light that forms an elliptical light spot may be simply referred to as an elliptical beam. In this case, the length of the major axis is usually 10 to 1000 μm, and the length of the minor axis is usually 0.1 to 5 μm.
Here, the lengths of the major axis and the minor axis of the beam are defined from the half width when the light energy intensity distribution in the beam is measured. This beam shape also makes the short axis length 5 μm or less, further 2 μm or less, more preferably 1.5 μm or less in order to facilitate local heating and rapid cooling in the short axis direction. The short axis length is preferably 0.1 μm or more, and more preferably 0.5 μm or more in order to maintain the depth of focus to some extent.

  In initialization by bulk erase, for example, when using a disk-shaped (planar ring shape) recording medium, the minor axis direction of the elliptical beam is made to substantially coincide with the circumferential direction, and the minor axis is rotated around the circumference of the disk. The entire surface can be initialized by scanning in the direction and moving the major axis in the diameter (radius) direction every round (one rotation). In this way, a polycrystalline structure oriented in a specific direction can be realized with respect to the light spot of the recording / reproducing focused light scanned along the track in the circumferential direction. FIG. 2 of 208143). The radial movement may be continuously performed during one rotation. Further, the movement in the radial direction may be performed once per rotation or every constant scanning distance in the circumferential direction.

The generation of an elliptical light spot is, for example, disclosed in Japanese Patent Application Laid-Open No. 2002-208143 [see particularly FIG. 1 (conceptual diagram of a light spot generating device) and the description related thereto] and a semiconductor laser and a cylindrical beam. A lens can be used.
The semiconductor laser is usually an end face emission type, and emits laser light in a super-elliptical shape. As shown in FIG. 1, the light intensity distribution in the condensed light spot is approximately Gaussian in the minor axis direction and trapezoidal in the major axis direction. The laser beam intensity of the light spot in the major axis direction usually has an inevitable intensity distribution due to the nature of the semiconductor laser. In FIG. 1 showing this inevitable intensity distribution, when the maximum value IPmax and the minimum value IPmin are assumed, the relationship between IPmax and IPmin is preferably (IPmax−IPimn) / (IPmax + IPmin) ≦ 0.2, and (IPmax More preferably, −IPimn) / (IPmax + IPmin) ≦ 0.1. (IPmax−IPimn) / (IPmax + IPmin) is ideally zero.

  It is preferable that the light spot moving distance in the radial direction per one rotation is shorter than the light spot long axis so as to be overlapped so that the same radius is irradiated with the laser light beam a plurality of times. Note that the optical axis of the elliptical beam may be inclined by about 0 to 45 degrees with respect to the radial direction. In this case, the length projected on the recording medium in the radial direction of the major axis is taken as the length of the major axis (radial direction). Then, as described above, the amount of movement in the radial direction for each rotation is made equal to or less than the length of the major axis of the projected light spot in the radial direction, thereby overlapping the locus of the spot in the previous round and the next round. Thus, uninitialization due to the gap is prevented, and reliable initialization is possible. Furthermore, non-uniformity of the initialization state derived from the energy distribution in the major axis direction (usually 10 to 20%) can be avoided. On the other hand, if the moving amount of the light spot in the radial direction for each rotation is too small, the same part is repeatedly irradiated with the light spot several tens of times. In this case, the other unfavorable crystal phase may be easily formed. For this reason, it is usually preferable that the amount of movement of the light spot in the radial direction for each turn is usually about ½ of the major axis of the light spot or ½ or more of the major axis of the light spot. The amount of movement of the light spot in the radial direction is about ½ of the major axis of the light spot, so that the same spot on the recording medium is irradiated with the light beam twice on average. For this reason, unevenness of the crystal state after initialization can be suppressed, and the possibility of causing thermal damage to the recording medium by irradiating the same portion on the recording medium twice or more can be reduced.

Further, the relative scanning linear velocity of the light spot with respect to the recording medium (in the present invention, the scanning linear velocity in initial crystallization (sometimes simply referred to as linear velocity) means the linear velocity in the circumferential direction) is optical. It is made different depending on the radial position of the recording area of the target information recording medium.
That is, in the initial crystallization process, the scanning linear velocity when scanning the light spot in the circumferential direction is increased toward the outer periphery of the recording medium, and the intensity of the focused light increases as the scanning linear velocity increases in the initial crystallization process. Raise. Then, the entire surface of the initial crystallization region is initialized. In other words, along with the radial movement of the light spot, the relative scanning linear velocity in the circumferential direction of the light spot with respect to the recording medium is increased toward the outer peripheral portion of the recording medium. “Increase the outer periphery” may be substantially constant in a certain section, but at least the innermost periphery of the region on the recording layer where the initial crystallization is performed and the innermost region of the region where the initial crystallization is performed. Looking at the outer periphery, it means that the scanning linear velocity at the outer periphery is increased. The scanning linear velocity at the outermost periphery is preferably 20 m / s or more, and more preferably 25 m / s or more.

The scanning linear velocity is preferably 15 m / s or more, more preferably 20 m / s or more, and further preferably 25 m / s or more over the entire surface of the disk initialization area. Particularly in the outermost peripheral portion, the scanning linear velocity is preferably 20 m / s or more, and more preferably 25 m / s or more.
In the conventional initialization apparatus, since the CLV method is used, the linear velocity is determined from the limit of the rotational speed of the disk (about 10000 rpm). Although the speed is determined by the limit of the rotational speed of the disk, the linear velocity at the outermost periphery of the initial crystallization region can be made higher. The upper limit of the linear velocity at the outermost periphery of the initial crystallization region is determined by the recording medium design (particularly the composition of the recording layer).

FIG. 2 can be given as a specific example showing the relationship between the radial position of the recording medium and the scanning linear velocity. 2A shows the CAV method, FIGS. 2B and 2C show the P-CAV method, FIG. 2D shows the ZCLV method, and FIG. 2E shows the P-CAV method / ZCLV method. The mixing of is shown.
More specifically, FIG. 2 (a) is a specific example of the CAV method, in which the rotation speed per unit time of the disk-shaped recording medium is constant at R0 over the entire initialization region.

  FIG. 2B is a specific example of the P-CAV system, and the scanning linear velocity increases in proportion to the radial position as in FIG. 2A, but the rate of increase is constant. This is different from the case. Such a P-CAV system is realized by a method as shown in the enlarged view of FIG. That is, the recording medium is divided into a plurality of regions in the radial direction. Then, the rotational speed (scanning linear velocity) is decreased when moving to the next region located in the outer circumferential direction while keeping the rotational speed substantially constant in one region (see enlargement 1 in FIG. 2B). Moreover, such a P-CAV system is implement | achieved by the method as shown in the enlarged view of the figure, for example. That is, the recording medium is divided into a plurality of regions in the radial direction. In one region, the scanning line speed is slightly lowered toward the outer periphery, and the scanning line speed is increased when moving to the next region located in the outer periphery direction (see enlargement 2 in FIG. 2B). The P-CAV system in (b) Enlargement 2 in the figure can also be considered as a Z-CLV system.

FIG. 2C shows another specific example of the P-CAV system, in which the CAV system has a constant rotation speed in the inner peripheral area, and the CLV system has a constant scanning line speed in the outer peripheral area.
FIG. 2D is a specific example of the Z-CLV method. The Z-CLV method is realized by repeating the following operations. That is, the recording medium is divided into a plurality of areas in the radial direction, and the scanning linear velocity is made substantially constant in one area. Then, when moving to the next region located in the outer peripheral direction, the scanning line speed is increased and the operation for setting the scanning line speed to a constant value is repeated.

FIG. 2 (e) is a special example, but is an example for more specifically explaining the gist that the scanning linear velocity generally increases toward the outer periphery. In other words, it is permissible to slightly reduce the scanning linear velocity (for example, 2-3 m / s) within a predetermined range (for example, a range of several mm) in the radial direction of the recording medium, unless it is contrary to the spirit of the present invention. Is done.
The movement of the light spot in the radial direction of the recording medium is caused to move in one direction from the inner periphery to the outer periphery of the region on the recording layer on which initial crystallization is performed, or on the region on the recording layer on which initial crystallization is performed. Moving in one direction from the outer periphery toward the inner periphery is preferable because mechanical control can be simplified. However, in the movement of the light spot, a slight retrograde is naturally allowed. For example, in the case of FIG. 2C, the following method can be performed. That is, after moving the CAV area of the inner peripheral portion in one direction from the inner periphery to the outer periphery, the same operation is performed by returning to the inner periphery again. Thereafter, the CLV region at the outer periphery is operated twice from the inner periphery to the outer periphery. Such an operation twice (or a plurality of times) is performed when it is desired to make the crystal state after initialization more uniform. If such a light spot and its radial movement method are determined, the initialization condition is determined by the scanning speed in the circumferential direction of the light spot and the power of the focused light.

In the present invention, the intensity of focused light (focused light power) is increased as the scanning linear velocity increases with the radial movement of the light spot.
When the scanning linear velocity is determined, the optimum focused light intensity Po (in this specification, the focused light intensity may be referred to as initialization power) Po is determined for the recording medium to be initialized. The lower limit Pomin of Po is a power required to raise the temperature of the recording layer to at least the crystallization temperature in order to crystallize the recording layer or to the melting point in the melt initialization. On the other hand, the upper limit Pomax of Po is a power that does not cause excessive thermal damage to the recording medium. Pomax / Pomin is usually 1 or more and 1.5 or less, and preferably 1.2 or less. The optimum initialization power Po determined in this way is considered to be substantially proportional to the scanning linear velocity.

In detail, Po is determined in consideration of the recording characteristics of the optical recording medium after the initial crystallization within the range of Pomin to Pomax. Examples of the recording characteristics of the optical information recording medium considered when determining Po include the following (1) to (3).
(1) Po is determined so that the difference between the reflectance of the optical information recording medium after initial crystallization and the reflectance of the erased portion after repeated rewriting and recording several times is as small as possible. Is done. The reflectance is measured by the light intensity that is reflected back to the reproducing optical system when the reproducing focused light is irradiated onto the optical information recording medium. In practice, the reflectance is an amount approximately proportional to the magnitude of the voltage output of the photodetector. In addition, it is preferable to determine Po so that the reflectance does not fluctuate due to uninitialization even locally.
(2) The reflected light in the unrecorded state of the optical information recording medium after initialization is detected by the photodetector. Then, Po is determined so that the noise measured with a spectrum analyzer or the like is as low as possible.
(3) Po is determined so that the jitter value in the second recording (the second recording is an overwrite on the optical information recording medium on which the recording has been performed once) is controlled within a predetermined range. The

  Here, the jitter value is a temporal fluctuation in detection timing of a mark position in so-called mark position recording and a mark end position in mark length (modulation) recording. The jitter value is usually represented by a standard deviation σ of temporal variation centering on the average value of detection timing. In the present invention, the jitter value corresponds to the general concept described in the reference book “Optical Disc Technology” (Radio Technology, Chapter 1, Section 1.7 Jitter). The jitter value is measured according to standard definitions and methods disclosed in the Orange Book, which is a CD, CD-R, and CD-RW standard, and in the DVD, DVD-R, and DVD-RW standard.

  Conditions for restricting the range of Po become stricter in the order of (1), (2), and (3). Further, in carrying out the measurement of (3) specifically, a determination method and specifications depending on a specific recording format are used, such as CD and DVD. The range of Po determined by the above (1) to (3) is usually a range narrower than Pomin to Pomax determined from the above physical constraints. Here, the lower limit value of Po determined by the above (1) to (3) is expressed as Pimin +, and the upper limit value of Po is expressed as Pimax +. In addition, an initialization power range determined by a difference between Pimin + and Pimax + at a certain scanning line speed is referred to as an initialization power margin and is represented by δPi.

  In the present invention, it is preferable to change the scanning linear velocity and the intensity of the focused light substantially continuously. Here, “substantially continuously changing the scanning line speed and the intensity of the focused light” means that if the scanning line speeds before and after switching the scanning line speed are Vib and Via, respectively, Via = Vib + ΔVi, Usually, in the range of ΔVi / Via ≦ 0.2, the intensity of the focused light is made constant. Here, ΔVi / Via is preferably 0.1 or less. By changing the scanning linear velocity in a fine range as described above, the recording medium can be uniformly crystallized. On the other hand, ΔVi / Via is usually 0.001 or more.

  When moving the light spot while overlapping the light spot trajectory by setting the amount of movement in the radial direction of the light spot to be less than the length of the long axis in the radial direction of the light spot so that no uninitialized part remains on the recording medium, The overlap of the spot trajectories is on the order of several tens of micrometers to several hundreds of micrometers. If the initialization conditions change greatly in such a small region of the order of several tens of μm to several hundreds of μm, the initialization state may vary greatly in the middle of the recording track, and the recording quality may vary in the middle of the track. growing. If there is such a sudden change in the recording track within one rotation, the possibility that the recording / reproducing apparatus (drive) malfunctions (and thus erroneous recording) increases. For this reason, it is preferable to change the scanning linear velocity in a fine range as described above.

Even if the ZCLV method of FIG. 2D is used, it is desirable to change ΔVi in small increments so that the above condition is satisfied when the scanning linear velocity is switched.
FIG. 3 conceptually shows the relationship between the scanning linear velocity and the initialization power. In the figure, it is preferable to change the scanning line speed Vi and the initialization power Pi within a band-shaped range determined by δPi. Ideally, it is preferable to change to Po linear in each Vi (path 1, FIG. 5A). Further, for example, as shown in the path 2 ((b) in the figure), it is possible to make Pi constant with respect to the change ΔVi in Vi, or in the path 3 ((c) in the figure). As described above, Pi may be changed by ΔPi according to ΔVi. Since such a route can be freely selected as long as such a route falls within the range of δPi in the figure, Pi can be changed according to Vi as in route 4 ((d) in the figure). .

  When FIG. 2 and FIG. 3 are combined, the setting method (relationship) of the position of the light spot, the scanning linear velocity, and the initialization power associated with the movement of the light spot in the radial direction of the recording medium is determined. For example, the scanning linear velocity at the radial position of the recording medium is determined by the P-CAV method as shown in FIG. 2C [see FIG. 4A], and as shown in FIG. When the initialization power is changed [see FIG. 4 (b)], the initialization power at the radial position of the recording medium is as shown in FIG. 4 (c).

Hereinafter, a more specific method of the initialization process will be described.
[B] Specific Method of Initial Crystallization in CAV Method In the present invention, it is preferable that the rotation speed (rotational speed) R0 per unit time of the recording medium is made constant in the initialization step.
R0 is not particularly limited as long as the rotational speed is such that the recording characteristics of the optical information recording medium obtained through the initialization step have a predetermined performance. R0 is preferably a maximum rotational speed Rmax set to satisfy the following condition.
(Conditions and setting method that must satisfy the maximum rotation speed Rmax)
(I) A plurality of recording media are prepared. One of the recording media is initialized by rotating the recording medium at an arbitrary number of revolutions in the innermost circumference of the recording area of the recording medium. That is, a plurality of recording media are prepared, and one of the recording media is rotated at an arbitrary rotation number, and at least the recording layer formed on the innermost track of the recording area is initially crystallized.
(Ii) Then, recording is performed twice on the innermost track that has been initially crystallized. Here, the second recording is an overwrite on the optical information recording medium on which the recording has been performed once.
(Iii) The jitter value J2 of the recording mark formed on the innermost track after the second recording is measured.
(Iv) Next, the jitter value J10 of the recording mark formed on the innermost track after 8 times of recording (10 times in total with the previous 2 times) is measured. .
(V) After initial crystallization is performed on another recording medium at a rotational speed different from the rotational speed of (i), the above (ii) to (iv) are performed.
(Vi) The operation of (v) is repeated while changing the recording medium.
(Vii) The relationship between J2 / J10 obtained from the jitter values J2 and J10 obtained from the recording medium initially crystallized at each rotational speed and the rotational speed at the time of initial crystallization is obtained. And R0 is set to the rotation speed which makes J2 / J10 1.6 or less.

Rmax, which will be described later, can be selected from the range of the rotational speed R0 that makes J2 / J10 1.6 or less.
In the above method, the jitter value is evaluated in the innermost track of the recording area for the following reason. That is, normally, in the initialization of the CAV method, the scanning linear velocity at the innermost circumference of the recording area is the smallest, and it is difficult to perform good initial crystallization. For this reason, if the recording quality after initialization is sufficient in the innermost track, the recording quality in the recording area located on the outer circumference (area where initialization is performed at a higher scanning linear velocity) is also good. Easy to do.

As a specific example of the innermost track, the innermost track of the recording area in the area where the initial crystallization is performed as shown in the AA ′ cross section of FIG. Note that in the AA ′ cross section of FIG. 5B, only the cross section of the substrate is shown for easy understanding of the innermost track position.
Further, the ratio (J2 / J10) of the jitter value J2 after the second recording and the jitter value J10 after the tenth recording in the innermost track is used as an evaluation index for the following reason. That is, in a normal optical information recording medium, a phenomenon in which the jitter value after the second recording increases is observed. Further, as the number of recording (overwrite) is further increased, the jitter value gradually decreases, and when recording is repeated about 10 times, the jitter value decreases to a constant value and is stabilized. For this reason, from the viewpoint of practical use, the jitter value that increases after the second recording is set to a predetermined range (specifically, the jitter value does not become excessively larger than the value when the jitter value is once stabilized). If it can be controlled within a range, it can be determined that a good initialization has been performed. In the present invention, the optimum rotational speed Rmax used in the initial crystallization step is selected from the range of the rotational speed R0 such that J2 / J10 is usually 1.6 or less, preferably 1.3 or less. J2 / J10 is ideally preferably 1.

FIG. 6 shows a conceptual diagram of the change of J2 / J10 obtained by changing the rotation speed R0. As shown in FIG. 6, Rmax can be arbitrarily set within the range of R0 such that J2 / J10 is 1.6 or less. Most preferably, in FIG. 6, R0 is set to Rmax such that J2 / J10 is the minimum value.
[C] Specific Method of Initial Crystallization in ZCAV System As a specific example of initializing the recording medium in the ZCAV system, the initial crystallization area is changed from the innermost periphery of the initial crystallization area of the recording medium. The region up to the outermost periphery [see FIG. 7B] is divided into a plurality of zones along the radial direction of the recording medium, and the intensity of the focused light irradiated in each zone is constant. Then, there is a method of gradually increasing the intensity of the focused light toward the outermost zone (increasing the intensity of the focused light in the zone on the outer peripheral side of the recording medium). That is, since the scanning linear velocity gradually increases toward the outermost periphery, it is preferable to increase the intensity of the focused light to be irradiated in order to surely crystallize the recording layer.

  As a method for gradually increasing the intensity of the laser beam toward the outermost zone, for example, the following method can be cited. That is, initialization is performed by changing the initialization laser intensity in each of the divided zones. Then, the relationship between the intensity of the initialization laser beam and the recording quality can be confirmed by measuring the jitter value, reflectance value, etc. after initialization. As a result, the optimum initialization laser intensity of each zone and the upper and lower limit values (allowable width for controlling the recording characteristics within a predetermined range) are obtained. Then, the initialization laser intensity in each zone is set from the optimum initialization laser intensity in each zone and its upper and lower limit values. As an example of setting the initialization laser intensity in each zone, FIG.

In the present invention, when performing the initial crystallization using the ZCAV method, the intensity of the focused light in each zone is set so that the jitter value in each zone satisfies the following condition after the initial crystallization. Is preferred.
(Conditions to satisfy the jitter value)
(I) In the optical information recording medium obtained through the initial crystallization, an arbitrary zone in the recording area is selected. In the zone, recording is performed twice on one track near the innermost periphery, one track near the center, and one track near the outermost periphery, and after recording twice on one track near the innermost periphery. Jitter value J2inzcav, jitter value J2outzcav after two recordings in one track near the outermost circumference, and jitter value J2midzcav after two recordings in one track near the center are measured.
(Ii) Recording is further performed 8 times (recorded 10 times in total with the previous 2 recordings) on one track near the center where recording was performed twice, and 1 track near the center is recorded. The jitter value J10midzcav after 10 times recording in the track is measured.
(Iii) J2inzcav, J2outzcav, J2midzcav and J10midzcav measured in (i) and (ii) above are
J2inzcav / J10midzcav ≦ 1.6
J2midzcav / J10midzcav ≦ 1.6
J2outzcav / J10midzcav ≦ 1.6
To satisfy.

  As described above, if the jitter value after the second recording is within a predetermined range with respect to the jitter value after the tenth recording over the entire zone, uniform initialization can be performed in that zone. You can see what is happening. If the above three expressions are satisfied in each zone existing in the recording area, it can be understood that uniform initialization is performed over the entire area in the recording area.

As an example of how to determine the zone, the zones 1 to n shown in FIGS. 8A and 8B can be mentioned. Then, for example, predetermined recording is performed on one track near the outermost periphery of zone k, one track near the center, and one track near the innermost periphery, and the jitter value is measured (see FIG. 9).
The following method can be given as an example of how to determine the intensity of the focused light in the zone k. That is, a plurality of recording media are prepared, and the initial crystallization of each recording medium is performed by changing the focused light intensity under the rotation speed of Rmax. Measure J2inzcav, J2outzcav, J2midzcav, and J10midzcav in zone k of the obtained plurality of optical information recording media,
J2inzcav / J10midzcav
J2outzcav / J10midzcav
J2midzcav / J10midzcav
(A value calculated from the above three expressions may be referred to as jitter characteristics). From the above measurement, the relationship between the intensity (initialization power) of the focused light and the jitter characteristics in the zone k can be obtained. from this result,
J2inzcav / J10midzcav ≦ 1.6
J2outzcav / J10midzcav ≦ 1.6
J2midzcav / J10midzcav ≦ 1.6
The initial crystallization process of the zone k may be performed within the range of the intensity of the focused light.

In the present invention, when performing the initial crystallization using the ZCAV method, the intensity of the focused light in each zone is set so that the reflectance value in each zone satisfies the following condition after the initial crystallization. Is also preferable.
(Conditions to satisfy the reflectance value)
(I) An arbitrary zone in the recording area of the optical information recording medium obtained through the initial crystallization is selected, and in the zone, one track near the innermost periphery, one track near the center, Recording is performed once on each track near the outer periphery. Then, after the first recording, the reflectance value Ref1inzcav of one track near the innermost periphery, the reflectance value Ref1midzcav of one track near the central portion, and the reflectance value Ref1outzcav of one track near the outermost periphery are obtained. Measure each.
(Ii) Nine times of recording is performed on each of the tracks recorded once (a total of 10 times is recorded in addition to the previously performed one time). Then, after the ten times recording, the reflectance value Ref10inzcav of one track near the innermost periphery, the reflectance value Ref10midzcav of one track near the central portion, and the reflectance value Ref10outzcav of one track near the outermost periphery are obtained. Measure each.
(Iii) The Ref1inzcav, Ref1midzcav, Ref1outzcav, Ref10inzcav, Ref10midzcav, and Ref10outzcav measured in (i) and (ii) above are | Ref1inzcav−Ref1outzcav | /Ref1midzcav≦0.05
｜ Ref10inzcav−Ref1inzcav | /Ref10inzcav≦0.05
｜ Ref10midzcav−Ref1midzcav | /Ref10midzcav≦0.05
｜ Ref10outzcav−Ref1outzcav | /Ref10outzcav≦0.05
Meet.

  As described above, the reflectance value after one-time recording takes a relatively close value within the entire zone, and the reflectance value after one-time recording and the reflectance value after ten-time recording are the entire zone. If the values are relatively close to each other, it can be seen that uniform initialization is performed within the zone. If the above four expressions are satisfied in each zone existing in the recording area, it is understood that uniform initialization is performed over the entire area in the recording area.

As an example of how to determine the zone, the zones 1 to n shown in FIGS. 8A and 8B can be mentioned. Then, for example, predetermined recording is performed on one track near the outermost periphery of zone k, one track near the center, and one track near the innermost periphery, and the reflectance value is measured (see FIG. 9).
The following method can be given as an example of how to determine the intensity of the focused light in the zone k. That is, a plurality of recording media are prepared, and the initial crystallization of each recording medium is performed by changing the focused light intensity under the rotation speed of Rmax. Measure Ref1inzcav, Ref1midzcav, Ref1outzcav, Ref10inzcav, Ref10midzcav, and Ref10outzcav in zone k of the obtained plurality of optical information recording media,
| Ref1inzcav−Ref1outzcav | / Ref1midzcav
| Ref10inzcav−Ref1inzcav | / Ref10inzcav
| Ref10midzcav−Ref1midzcav | / Ref10midzcav
| Ref10outzcav−Ref1outzcav | / Ref10outzcav
(A value calculated from the above four formulas may be referred to as a reflectance characteristic). From the above measurement, the relationship between the intensity (initialization power) of the focused light and the reflectance characteristics in the zone k can be obtained. from this result,
| Ref1inzcav−Ref1outzcav | /Ref1midzcav≦0.05
| Ref10inzcav−Ref1inzcav | /Ref10inzcav≦0.05
| Ref10midzcav−Ref1midzcav | /Ref10midzcav≦0.05
| Ref10outzcav−Ref1outzcav | /Ref10outzcav≦0.05
The initial crystallization process of the zone k may be performed within the range of the intensity of the focused light.

Although it is desirable to use an overlapping portion of initialization conditions determined from both the setting based on the jitter value and the setting based on the reflectance value, an initialization condition determined from either one may be used.
[D] Change of laser light between zones in initial crystallization by ZCAV method In the initialization of the ZCAV method, it is preferable to increase the initialization laser intensity toward the outer zone. This increase in laser intensity may be continuously changed as the light spot moves in the outer circumferential direction (for example, see FIG. 3A). Further, the increase in the laser intensity may take a constant value for each zone and gradually increase as it goes to the outer zone (for example, FIG. 3B). Further, a method may be used in which the laser intensity is continuously increased within each zone while the initialization laser intensity is increased by a predetermined amount between the zones (for example, FIG. 3C). When the laser intensity changes between the zones (for example, in the case of FIGS. 3B and 3C), it is preferable to control the initialization laser intensity as follows.

Specifically, for example, the following two methods can be mentioned.
In the first method, of two adjacent zones in the recording area, a zone located on the inner circumference side is designated as zone A, and a zone located on the outer circumference side is designated as zone B. The initialization laser intensity of the zone A is Pin, and the initialization laser intensity of the zone B is Pout. In performing the initial crystallization, the above-mentioned Pin and Pout, and the minimum initialization laser intensity PJmin and the maximum initialization laser intensity PJmax measured by the following method are PJmin ≦ Pin ≦ Pout ≦ PJmax.
To satisfy.

Here, PJmin and PJmax are preferably set by the following method.
(Setting method of maximum initialization laser intensity PJmax and minimum initialization laser intensity PJmin)
J2zoneAout is a jitter value when recording is performed twice on one track in the vicinity of the outermost periphery in the zone A in the optical information recording medium, and the vicinity of the central portion in the zone A in the optical information recording medium. J10 zoneAmid is the jitter value when recording is performed 10 times on one track, and the jitter value when recording is performed twice on one track near the innermost circumference in the zone B of the optical information recording medium. When J2zoneBin
The J2zoneAout, the J2zoneBin, and the J10zoneAmid are
J2zoneAout / J10zoneAmid ≦ 1.6
J2zoneBin / J10zoneAmid ≦ 1.6
The minimum value of the laser intensity that satisfies the above is PJmin, and the maximum value of the laser intensity is PJmax.

As described above, if the jitter value after recording twice takes a relatively close value in the boundary region between the two zones, it is determined that the same initialization can be performed between both zones. can do.
Specific examples of the zone A, the zone B, the track near the outermost periphery of the zone A, the track near the center of the zone A, and the track near the innermost periphery of the zone B can be shown in FIG. The following methods can be given as specific methods for setting the PJmin and PJmax. For example, a plurality of recording media having the same layer configuration are prepared, and zones A and B of one of the recording media are initialized with the same initialization laser intensity, and the optical information recording medium “J2zoneAout / J10zoneAmid”, Obtain "J2zoneBin / J10zoneAmid" respectively. Next, zones A and B are initialized with different initialization laser intensities for the other recording media, and the optical information recording media “J2zoneAout / J10zoneAmid” and “J2zoneBin / J10zoneAmid” are used. ”Respectively. The above work is repeated, and the work for obtaining “J2zoneAout / J10zoneAmid” and “J2zoneBin / J10zoneAmid” of each optical information recording medium is performed. Then, the relationship between the initialization laser intensity and “J2zoneAout / J10zoneAmid” and “J2zoneBin / J10zoneAmid” is plotted. From this result, Pin J and Pout are Pin ≦ Pout where PJmin is the minimum value of the initialization laser intensity and “JJzoneAin / J10zoneAmid” and “J2zoneBin / J10zoneAmid” are both 1.6 or less, and the maximum value is PJmax. While maintaining this relationship, it may be changed within the range of PJmin to PJmax (see FIG. 11A).

In the second method, of two adjacent zones in the recording area, a zone located on the inner circumferential side is designated as zone A, and a zone located on the outer circumferential side is designated as zone B. The initialization laser intensity of the zone A is Pin, and the initialization laser intensity of the zone B is Pout. When performing the initial crystallization, the above-mentioned Pin and Pout, and the minimum initialization laser intensity PRmin and the maximum initialization laser intensity PRmax measured by the following method are: PRmin ≦ Pin ≦ Pout ≦ PRmax
To satisfy.

Here, it is preferable that PRmin and PRmax are set so as to satisfy the following conditions.
(Conditions for satisfying the maximum initialization laser intensity PRmax and the minimum initialization laser intensity PRmin (setting method))
The reflectance value when recording is performed once on one track near the outermost periphery of the zone A in the optical information recording medium is RefzoneAout, and the reflectance value is 1 near the center of the zone A in the optical information recording medium. The reflectance when recording is performed once on the track is RefzoneAmid, and the reflectance value when recording is performed once on one track near the innermost circumference of the zone B in the optical information recording medium is RefzoneBin. And when
｜ RefzoneAout−RefzoneBin ｜ /RefzoneAmid≦0.05
The minimum value of the laser intensity that satisfies the above is PRmin, and the maximum value of the laser intensity is PRmax.

As described above, if the reflectance value after one recording is relatively close to the boundary area between the two zones, it is possible to perform substantially the same initialization between both zones. Judgment can be made.
As specific examples of zone A, zone B, a track near the outermost periphery of zone A, a track near the center of zone A, and a track near the innermost periphery of zone B, FIG. The following methods can be given as specific methods for setting the PRmin and PRmax. For example, a plurality of recording media having the same layer structure are prepared, and zones A and B of one of the recording media are initialized with the same initialization laser intensity, and the optical information recording medium “| RefzoneAout−RefzoneBin | / RefzoneAmid ". Next, the zones A and B are initialized with a different initialization laser intensity from the previous recording medium for another recording medium, and the optical information recording medium “| RefzoneAout−RefzoneBin | / RefzoneAmid” is set. Ask. The above operation is repeated, and the operation of obtaining “| RefzoneAout−RefzoneBin | / RefzoneAmid” of each optical information recording medium is performed. Then, the relationship between the initialization laser intensity and “| RefzoneAout−RefzoneBin | / RefzoneAmid” is plotted. From this result, Pin and Pout have a relationship of Pin ≦ Pout, where PRmin is the minimum value of the initialization laser intensity so that “| RefzoneAout−RefzoneBin | / RefzoneAmid” is 0.05 or less, and PRmax is the maximum value. What is necessary is just to change in the range of said PRmin-PRmax, hold | maintaining (refer FIG.11 (b)).

As described above, the initialization laser is usually elliptical and has a long axis set parallel to the radial direction, and the length of the long axis covers a plurality of tracks. Usually, the moving distance in the radial direction for each rotation of the laser is made shorter than the length of the long axis of the laser, and the same portion of the recording medium is irradiated with the initialization laser a plurality of times. . Here, the track position of the recording medium and the position control of the initialization laser may not always be synchronized. For this reason, depending on the timing at which the laser intensity is switched from Pin to Pout, the region near the boundary with the zone A in the outer zone B is initialized with the initialization laser intensity of the zone A, or conversely the zone B in the inner zone A. In some cases, the region near the boundary is initialized with the initialization laser intensity of zone B. Furthermore, depending on the timing at which the laser intensity is switched from Pin to Pout, the boundary region between zones A and B may be initialized with the initialization laser intensity of both zones (see FIG. 10).
[E] Initial crystallization method in ZCLV method, determination method of initialization laser intensity in zone When initialization is performed in ZCLV method, from the innermost periphery of the initial crystallization region to the outermost periphery of the initial crystallization region in the recording medium It is preferable to divide the region up to [see FIG. 12B] into a plurality of zones so that the rotational speed at the innermost circumferential position in each zone is constant. That is, in this initialization method, for example, as shown in FIG. 12A, a plurality of zones [zone 1 to zone n in FIG. 12A] are provided in the radial direction of the recording medium. In the innermost circumference, the rotational speed is set to be constant at R0. Further, initial crystallization is performed so that the linear velocity is constant from the innermost circumference to the outermost circumference in each zone [see FIG. 12 (a)].

In this initialization method, it is preferable to set the laser light intensity in each zone so that the jitter value in each zone in the optical information recording medium that has been crystallized initially satisfies the following conditions.
(Conditions to satisfy the jitter value)
(I) In the optical information recording medium, an arbitrary zone in the recording area is selected. Then, recording is performed twice on one track near the center of the zone, and the jitter value J2midzclv after recording twice is measured.
(Ii) Further, 8 recordings are performed on one track in the vicinity of the central portion (a total of 10 recordings with the previous two recordings), and the jitter value J10midzclv after 10 recordings is measured.
(Iii) J2midzclv and J10midzclv measured in (i) and (ii) above are
J2midzclv / J10midzclv ≦ 1.6
Meet.

  In the ZCLV system, initialization is performed at a constant linear velocity in each zone, and thus there is an advantage that it is easy to ensure uniformity of initialization in the zone. Therefore, if the jitter value after the second recording is within a predetermined range with respect to the jitter value after the tenth recording in the track near the center of each zone, uniform initialization is performed in that zone. It can be considered that If the above formula is satisfied in each zone in the recording area, it can be seen that uniform initialization is performed over the entire area in the recording area.

Furthermore, in the present invention, it is also preferable to set the intensity of the laser beam in each zone so that the reflectance value in each zone after the initial crystallization satisfies the following conditions.
(Conditions to satisfy the reflectance value)
(I) An arbitrary zone in the recording area of the optical information recording medium is selected. Then, recording is performed once per track near the center in the zone, and the reflectance value Ref1midzclv of one track near the center is measured.
(Ii) Nine times of recording is performed on one track near the center (recording a total of 10 times in total with the previous one), and the reflection of one track near the center after 10 times recording. Measure the rate value Ref10midzclv.
(Iii) Ref1midzclv and Ref10midzclv measured in (i) and (ii) above are | Ref10midzclv−Ref1midzclv | /Ref10midzclv≦0.05
Meet.

  As described above, in the ZCLV method, initialization is performed at a constant linear velocity in each zone, and thus there is an advantage that it is easy to ensure uniformity of initialization in the zone. For this reason, if the reflectance value after one-time recording and the reflectance value after ten-time recording are relatively close to each other in the center of the zone, uniform initialization is performed in that zone. It can be considered that If the above expression is satisfied in each zone existing in the recording area, it can be seen that uniform initialization is performed over the entire surface of the recording area.

Although it is desirable to use an overlapping portion of initialization conditions determined from both the setting based on the jitter value and the setting based on the reflectance value, an initialization condition determined from either one may be used.
[F] Specific example 1 of laser beam changing method
In the initialization of the ZCLV method, it is preferable to increase the initialization laser intensity toward the outer zone. This increase in laser intensity may be continuously changed as the light spot moves in the outer circumferential direction (for example, see FIG. 3A). Further, the increase in the laser intensity may take a constant value for each zone and gradually increase as it goes to the outer zone (for example, FIG. 3B). Further, a method may be used in which the laser intensity is continuously increased within each zone while the initialization laser intensity is increased by a predetermined amount between the zones (for example, FIG. 3C). When the laser intensity changes between the zones (for example, in the case of FIG. 3B), it is preferable to control the initialization laser intensity as follows.

Hereinafter, two specific examples of the method for setting the change amount of the initialization laser intensity between the zones in the case of FIG. 3B will be described first.
In the first method, of two adjacent zones in the recording area, a zone located on the inner circumference side is designated as zone A, and a zone located on the outer circumference side is designated as zone B. The initialization laser intensity of the zone A is Pin, and the initialization laser intensity of the zone B is Pout. In performing the initial crystallization, it is preferable that the Pin and the Pout satisfy the following conditions.
(Conditions to be satisfied by Pin and Pout)
(I) Prepare two recording media,
(Ii) In one of the two recording media, the zone A is initially crystallized with an initialization laser intensity Pin, and the zone B is initially crystallized with an initialization laser intensity Pout. Then, the jitter value J10zoneAPin after recording one track near the center of the zone A 10 times and the jitter value J10zoneBPout after recording one track near the center of the zone B 10 times are measured.
(Iii) In another recording medium of the two recording media, the zone A is initially crystallized with an initialization laser intensity Pout, and the zone B is initially crystallized with an initialization laser intensity Pin. Then, the jitter value J2zoneAPout after recording one track near the center of the zone A twice and the jitter value J2zoneBPin after recording one track near the center of the zone B twice are measured.
(Iv) J10zoneAPin and J2zoneAPout measured in (ii) and (iii) above are:
J2zoneAPout / J10zoneAPin ≦ 1.6
Satisfy the relationship
J10zoneBPout and J2zoneBPin measured in the above (ii) and (iii)
J2zoneBPin / J10zoneBPout ≦ 1.6
Satisfy the relationship.

  As described above, depending on the timing at which the laser intensity is switched from Pin to Pout, the region near the boundary with the zone A in the outer zone B is initialized with the initialization laser intensity of the zone A, or conversely in the inner zone A. A region near the boundary with zone B may be initialized with the initialization laser intensity of zone B. Furthermore, depending on the timing at which the laser intensity is switched from Pin to Pout, the boundary region between zones A and B may be initialized with the initialization laser intensity of both zones.

  Therefore, the jitter value after the second recording in the zone A and the zone B in the vicinity of the boundary between the zone A and the zone B (which tends to increase with respect to the first recording after the initialization) The jitter value after the second recording of zone A in the vicinity of the boundary between zone A and zone B (the jitter value after the second recording of desired zone A) or the zone B is initialized only by Pout. There is a possibility that it becomes larger than the jitter value after the second recording of the zone B in the vicinity of the boundary between the zone A and the zone B (the jitter value after the second recording of the desired zone B).

  Therefore, when the zone A is initialized with Pout with respect to the jitter value after 10 recordings in the vicinity of the central portion of the zone A when the zone A is initialized with Pin (the state where the jitter value is lowered and once stabilized). The jitter value after recording twice in the vicinity of the center of the zone A is set within a predetermined range. Then, when zone B is initialized with Pin for the jitter value after 10 recordings in the vicinity of the center of zone B when zone B is initialized with Pout (the state where the jitter value is lowered and once stabilized) The jitter value after recording twice in the vicinity of the central portion of the zone B is set within a predetermined range. In this way, it can be determined that initialization of substantially the same state has been completed in both zones A and B.

Specific examples of zone A, zone B, a track near the center of zone A, and a track near the center of zone B can be shown in FIG. The following methods can be given as specific methods for setting the Pin and Pout.
First, the range of initialization laser intensity to be satisfied in each zone is obtained from the above-mentioned “Initial crystallization method in [E] ZCLV method, determination method of initialization laser intensity in zone”. For this reason, desired initialization laser intensities Pin and Pout exist for zones A and B, respectively. The temporary (temporary) Pin that initializes the zone A is Pin ′, and the temporary (temporary) Pin that initializes the zone B is Pout ′. Zones A and B of one recording medium are initialized with the initialization laser intensities of Pin ′ and Pout ′, respectively, and the values of J10zoneAPin and J10zoneBPout are determined.

  Next, a plurality of recording media having the same layer structure as the recording medium are prepared. Then, after the zones A and B in each recording medium are initialized with the same initialization laser intensity (the initialization laser intensity in each recording medium is different), the vicinity of the central part of the zones A and B The jitter value after recording twice (jitter value after twice recording) is measured. Then, the values of “jitter value after twice recording / J10zoneAPin” and “jitter value after twice recording / J10zoneBPout” are plotted against the initialization laser intensity (see FIG. 14). FIG. 14 is a conceptual diagram showing the relationship between the initialization laser intensity and “jitter value after twice recording / J10zoneAPin” and “jitter value after twice recording / J10zoneBPout”. If only zone A is considered, the initialization laser intensity can be set in the range of β in FIG. On the other hand, considering only the zone B, the initialization laser intensity can be set in the range of γ in FIG. Then, considering that both zones A and B are initialized well, it is necessary to set Pin and Pout within the range of α in the figure (α should satisfy Pin and Pout). Range). Therefore, when the above Pin ′ and Pout ′ are out of α in the figure, they may be set within the range of α.

In the second method, of two adjacent zones in the recording area, a zone located on the inner circumferential side is designated as zone A, and a zone located on the outer circumferential side is designated as zone B. The initialization laser intensity of the zone A is Pin, and the initialization laser intensity of the zone B is Pout. In performing the initial crystallization, it is preferable that the Pin and the Pout satisfy the following conditions.
(Conditions to be satisfied by Pin and Pout)
(I) Prepare two recording media,
(Ii) In one of the two recording media, initial crystallization is performed with respect to the zones A and B at an initialization laser intensity Pin. Then, the reflectance Ref1zoneAPin after recording one track near the center of the zone A once and the reflectance Ref1zoneBPin after recording one track near the center of the zone B once are measured.
(Iii) In the other recording medium of the two recording media, the zone A is initially crystallized with the initializing laser intensity Pout. Then, the reflectance Ref1zoneAPout after recording one track near the center of the zone A once is measured.
(Iv) Ref1zoneAPin, Ref1zoneBPin, and Ref1zoneAPout measured in (ii) and (iii) above are
｜ Ref1zoneAPout－Ref1zoneBPin ｜ ／Ref1zoneAPin≦0.05
Satisfy the relationship.

  As described above, depending on the timing at which the laser intensity is switched from Pin to Pout, the region near the boundary with the zone A in the outer zone B is initialized with the initialization laser intensity of the zone A, or conversely in the inner zone A. A region near the boundary with zone B may be initialized with the initialization laser intensity of zone B. Furthermore, depending on the timing at which the laser intensity is switched from Pin to Pout, the boundary region between zones A and B may be initialized with the initialization laser intensity of both zones.

  For this reason, the reflectivity of zone A and zone B near the boundary between zone A and zone B is the reflectivity of zone A near the boundary between zone A and zone B when zone A is initialized with only Pin. There is a possibility that the zone B may be larger or smaller than the reflectance of the zone B near the boundary between the zone A and the zone B when the zone B is initialized only by Pout.

  Therefore, the reflectance when the zone A is initialized with Pout and the reflectance when the zone B is initialized with Pin are within a predetermined range with respect to the reflectance when the zone A is initialized with Pin. As a result, even if the reflectivity of the zone A and the zone B fluctuates due to the change in the intensity of the initialization laser near the boundary between the zone A and the zone B, the state is almost the same in both the zones A and B. It can be determined that initialization has been completed.

Specific examples of zone A, zone B, a track near the center of zone A, and a track near the center of zone B can be shown in FIG. The following methods can be given as specific methods for setting the Pin and Pout.
First, in the above-mentioned “[E] Initial crystallization method in the ZCLV method, how to determine the initialization laser intensity in the zone”, the range of the initialization laser intensity to be satisfied is obtained for each zone. For this reason, a predetermined initialization laser intensity Pin also exists for the zone A. A temporary (temporary) Pin that initializes Zone A is Pin ′. The zone A of one recording medium is initialized with the initialization laser intensity of Pin ′, and the reflectance Ref1zoneAPin after one recording in the track near the center of the zone A is measured.

  Next, a plurality of recording media having the same layer structure as the recording medium are prepared. Then, each recording medium is initialized with different initialization laser intensities. Thereafter, the reflectance value after recording once in zones A and B is measured at the center of each zone. Then, the value of “| (reflectance after one recording in zone A) − (reflectance after one recording in zone B) | / Ref1zoneAPin” is plotted against the initialization laser intensity in zone A (FIG. 15). reference). FIG. 15 is a conceptual diagram showing the relationship between the initialization laser intensity and “| (reflectance after one recording in zone A) − (reflectance after one recording in zone B) | / Ref1zoneAPin”. . Pout needs to be set within the range of α in the figure (α indicates a range that Pout should satisfy with respect to Pin ′, which is a temporary Pin).

As described above, the initialization laser is usually elliptical and is set so that the major axis is parallel to the radial direction. The length of the long axis covers a plurality of tracks. The moving distance in the radial direction for each rotation of the laser is made shorter than the length of the long axis of the laser so that the same portion of the recording medium is irradiated with the initialization laser a plurality of times. Here, the track position of the recording medium and the position control of the initialization laser may not always be synchronized. For this reason, depending on the timing at which the laser intensity is switched from Pin to Pout, the region near the boundary with the zone A in the outer zone B is initialized with the initialization laser intensity of the zone A, or conversely the zone B in the inner zone A. In some cases, the region near the boundary is initialized with the initialization laser intensity of zone B. Furthermore, depending on the timing at which the laser intensity is switched from Pin to Pout, the boundary region between zones A and B may be initialized with the initialization laser intensity of both zones (see FIG. 10). This is the same as the initialization of the ZCAV method.
[G] Specific example 2 of laser beam changing method
Next, two specific examples of the method for setting the change amount of the initialization laser intensity between the zones in the case of FIG. 3C will be described. Of the two adjacent zones in the recording area of the recording layer, the zone located on the inner circumferential side is zone A, the zone located on the outer circumferential side is zone B, and the focused light (initializing laser) intensity in zone A Is Pin, and the focused light (initializing laser) intensity in Zone B is Pout.

  As a first method, the minimum value that Pin can take is Pinmin, the maximum value is Pinmax, the minimum value Pout can take is Poutmin, and the maximum value is Poutmax. Then, in the initialization process, as the initialization laser goes in the outer circumferential direction in the zone A, Pin is gradually increased within the range from the above Pinmin to the above Pinmax. Then, the Pin value at the outermost periphery of the zone A is PinzoneAout. On the other hand, as the initialization laser moves in the outer peripheral direction in the zone B, Pout is gradually increased within a range from the Poutmin to the Poutmax. The value of Pout in the innermost circumference of zone B is PoutzoneBin.

And the relationship between the PinoutBin and the PinzoneAout is
PoutzoneBin ＝ PinzoneAout
It is preferable that This control method has an advantage that initialization in the vicinity of the boundary region of each zone can be easily performed uniformly because there is no change in the initialization laser intensity between the zones. As a particularly preferable method of the above control, as shown in FIG. 3A, there can be mentioned a method in which the initialization laser intensity changes continuously (linearly) as the scanning linear velocity increases. . However, even if “PoutzoneBin = PinzoneAout”, an error of about ± 10% is allowed between PoutzoneBin and PinzoneAout.

Even when the PoutzoneBin and the PinzoneAout are not set to the same intensity, it is preferable to satisfy PoutzoneBin> PinzoneAout and minimize the difference between the PoutzoneBin and the PinzoneAout. Thus, if the difference between PinoutBin and PinzoneAout is minimized, the initialization of the boundary region between zones A and B can be made uniform easily.
[H] Initial Crystallization in P-CAV Method As described above, the initialization method of the present invention can be a P-CAV method (see FIGS. 2B, 2C, and 4). As a specific method of the P-CAV method, for example, the number of rotations until the predetermined radial position of the recording medium is reached from the innermost peripheral position of the initial crystallization region in the recording layer of the recording medium toward the outer peripheral direction. An initialization method in which the scanning linear velocity is constant between R0 and the predetermined radial direction position to the outermost peripheral position of the initial crystallization region of the recording layer can be exemplified (FIG. 2 (c), FIG. 4). reference).

The linear velocity V1 of the light spot on the optical information recording medium at the predetermined radial position is preferably a maximum linear velocity Vmax defined so as to satisfy the following condition.
(Conditions that the maximum linear velocity must satisfy)
(I) The recording layer formed on an arbitrary track in the initial crystallization region is initially crystallized at an arbitrary linear velocity.
(Ii) Recording is performed twice on the track. Here, the second recording is an overwrite on the optical information recording medium on which the recording has been performed once.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Further, recording is performed 8 times (a total of 10 times is recorded with the previous 2 times), and the jitter value J10 of the recording mark formed after the 8th recording is measured.
(V) The above (i) to (iv) are repeated while changing the linear velocity.
(Vi) The linear velocity that makes J2 / J10 obtained from the jitter values J2 and J10 obtained at the respective linear velocities 1.6 or less is the maximum linear velocity Vmax.

The method for setting Vmax can be set following the method for setting the maximum rotational speed Rmax. Vmax is preferably set to a value at which J2 / J10 is minimized within a range of J2 / J10 ≦ 1.6.
In addition, the following method can be mentioned as a specific example of the said P-CAV system. That is, the maximum rotation speed of the initialization device is set at the innermost circumference, and the rotation speed is kept constant in a certain region, thereby increasing the linear velocity toward the outer circumference. When reaching a linear velocity that minimizes J2 / J10 within the radius of the disk, the minimum value of J2 / J10 is maintained as CLV after the radial position.
[I] Initial crystallization at a speed exceeding the upper limit of the erasing linear velocity of the optical information recording medium In the present invention, in the initial crystallization step, the maximum linear velocity used for initial crystallization of the recording layer is determined as the optical information. It is preferable that the amorphous linear mark formed on the recording medium has a maximum linear velocity that can be erased. That is, it is preferable that the maximum linear velocity at which the recording medium is initially crystallized is equal to or higher than the maximum linear velocity at which the amorphous mark on the medium can be erased.

In setting the scanning linear velocity at the time of initial crystallization, the scanning at the time of initializing crystallization is conventionally performed with respect to the maximum linear velocity LVmax that can erase the amorphous mark of the optical information recording medium after initialization. In general, the linear velocity is set to a value equal to or slightly lower than LVmax.
Here, LVmax means that when an amorphous mark is recorded on an optical information recording medium, and then the recording focused light beam set to the erasing power is changed by changing the linear velocity and irradiating with a direct current, it is erased. The maximum linear velocity is over 20 dB. When overwriting is performed at a recording linear velocity higher than LVmax, unerased portions are generated and the recording quality is remarkably deteriorated. For this reason, it can be said that LVmax is the highest linear velocity that can be overwritten.

  Note that the remaining unerased is a phenomenon that the amorphous mark remains without being recrystallized and the recording layer is melted by the erasing power, so that the amorphous region is formed again without being recrystallized. It means two phenomena. In particular, the latter phenomenon is called re-amorphization. This is a phenomenon in which an amorphous state is formed instead of recrystallization by irradiation of a recording focused beam with an erasing power intended for erasing by recrystallization.

  Conventionally, in initialization of a disk-shaped recording medium, it has been usual to set the scanning linear velocity at the time of initial crystallization to LVmax or less over the entire surface of the disk. Even in the melt initialization, as long as this condition was satisfied, re-amorphization did not occur, and all the crystals were recrystallized to obtain a good initial crystal state. On the other hand, when the scanning linear velocity at the time of initial crystallization is higher than LVmax, re-amorphization tends to occur.

In contrast, in the recording method of the present invention, in particular, in an optical information recording medium having an LVmax of approximately 20 m / s, re-amorphization can be achieved even if the scanning linear velocity at the time of initial crystallization is set to LVmax or more. As a result, it was found that a better initial crystal state was obtained.
Specific examples of the optical information recording medium as described above LVmax is approximately 20 m / s, the composition of the recording layer, the above-mentioned _{Ge x (In w Sn 1-} w) y Te z Sb 1-xyz An example can be given. Here, the Sb content is higher than any of the Ge content, the In content, the Sn content, and the Te content, and x, y, z, and w representing the atomic ratio are as follows: Satisfy (i) to (vi).
(I) 0 ≦ x ≦ 0.3
(Ii) 0.07 ≦ yz
(Iii) w × y−z ≦ 0.1
(Iv) 0 <z
(V) (1-w) × y ≦ 0.35
(Vi) 0.35 ≦ 1-xyz
[J] Number and Width of Zones When initialization is performed using zones in the CAV, ZCAV, ZCLV method, etc. described above, the zones are set as follows.

That is, the number of zones is usually 2 or more, preferably 3 or more. On the other hand, the number of zones is usually 50 or less, preferably 30 or less, more preferably 10 or less. Within the above range, initialization can be performed without performing complicated control.
Further, although the width of one zone depends on the size of the recording medium, it is usually 1 mm or more, preferably 2 mm or more, while the width of one zone is usually 20 mm or less, preferably 10 mm or less. Within the above range, initialization can be performed without performing complicated control.

However, in the case of the P-CAV system, since there is a region where the linear velocity is constant, the zone is set as follows.
That is, the number of zones is usually 2 or more, preferably 3 or more. On the other hand, the number of zones is usually 50 or less, preferably 30 or less, more preferably 10 or less. Within the above range, initialization can be performed without performing complicated control.

Further, although the width of one zone depends on the size of the recording medium, it is usually 1 mm or more, preferably 2 mm or more, while the width of one zone is usually 35 mm or less. Within the above range, initialization can be performed without performing complicated control.
(3) Initialization apparatus [A] The initialization apparatus of the present invention will be described below with reference to FIG.

  As shown in FIG. 16, the initialization apparatus 1 is an apparatus for initial crystallization of a recording layer 2 of a recording medium 2 having a phase change recording layer on a disk-shaped substrate. A spindle motor 3 that rotates, a motor driver 4 that drives the spindle motor 3, an initialization head (laser head) 5, an initialization head driver 6 that drives the initialization head 5, and control of each device are performed. And a control unit (for example, including a CPU and a memory) 7.

Here, the initialization head 5 is configured to include, for example, a laser diode, an actuator used for focusing and tracking, and the like. The initialization head driver 6 includes a laser driver (laser diode driver) that drives a laser diode and a driver that drives an actuator.
Then, the control unit 7 executes speed control of the scanning linear velocity, intensity control of focused light (laser light), spindle motor rotation speed control, and the like in the above-described initial crystallization process.
[B] Specifically, the control unit 7 controls the spindle motor 3 and the initialization head 5 to irradiate a laser beam (focused light) on the recording layer to form a light spot around the recording medium. Scan in the direction. In particular, in the present invention, the control unit 7 increases the scanning linear velocity when scanning the light spot in the circumferential direction toward the outer peripheral portion of the recording medium 2.

Here, the control unit 7 is configured to increase the intensity of the focused light as the scanning linear velocity increases. Then, the entire surface of the initial crystallization region is initialized.
Further, it is preferable that the control unit 7 is configured so as to make the rotation speed R0 per unit time of the recording medium constant. The conditions to be satisfied by R0 are as described above.
[C] It is also preferable that the control unit 7 is configured to rotate the recording medium based on the rotation speed R0 set so as to satisfy the following conditions.
(I) A plurality of recording media are prepared, and one of the recording media is rotated at an arbitrary number of revolutions, and at least the recording layer formed on the innermost track of the recording area of the recording medium is initially crystallized. Turn into.
(Ii) Recording is performed twice on the innermost track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) After initial crystallization is performed on another recording medium at a rotational speed different from the rotational speed of (i), the above (ii) to (iv) are performed.
(Vi) The operation of (v) is repeated while changing the recording medium.
(Vii) The relationship between J2 / J10 obtained from the jitter values J2 and J10 obtained from the recording medium initially crystallized at each rotational speed and the rotational speed at the time of initial crystallization is obtained. And R0 is set to the rotation speed which makes J2 / J10 1.6 or less.
[D] Further, the initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, and the control unit 7 makes the intensity of the focused light irradiated in each zone constant, and the zone on the outer peripheral side of the recording medium. It is preferable to be configured to increase the intensity of the focused light. Further, when performing the initial crystallization of the recording layer, it is also preferable that the intensity of the focused light in each zone is controlled based on the intensity of the focused light in each zone set so as to satisfy the following conditions. .
(I) In each zone in the recording area of the optical information recording medium obtained through the initial crystallization, one track near the innermost periphery, one track near the central portion, and one track near the outermost periphery, respectively. 2 times recording, jitter value J2inzcav after 2 times recording in 1 track near innermost circumference, jitter value J2outzcav after 2 times recording in 1 track near outermost circumference, 2 times recording in 1 track near the center The subsequent jitter value J2midzcav is measured.
(Ii) Recording is further performed 8 times for one track near the center, and the jitter value J10midzcav after 10 times of recording is measured.
(Iii) J2inzcav, J2outzcav, J2midzcav and J10midzcav measured in (i) and (ii) are set so as to satisfy the following conditions.

J2inzcav / J10midzcav ≦ 1.6
J2midzcav / J10midzcav ≦ 1.6
J2outzcav / J10midzcav ≦ 1.6
[E] Further, the initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, and the control unit 7 makes the intensity of the focused light irradiated in each zone constant, and the zone on the outer peripheral side of the recording medium. It is preferable to increase the intensity of the focused light. Here, it is preferable to control the intensity of the focused light in each zone based on the intensity of the focused light in each zone set to satisfy the following conditions.
(I) In each zone in the recording area of the optical information recording medium obtained through the initial crystallization, one track near the innermost periphery, one track near the central portion, and one track near the outermost periphery, respectively. After recording once, reflectivity value Ref1inzcav of one track near the innermost track after one recording, reflectivity value Ref1midzcav of one track near the center, and reflectivity value Ref1outzcav of one track near the outermost track Measure each.
(Ii) Recording is further performed 9 times on each track, and after 10 recordings, the reflectance value Ref10inzcav of one track near the innermost periphery, the reflectance value Ref10midzcav of one track near the center, and 1 near the outermost periphery. The reflectance value Ref10outzcav of the track is measured.
(Iii) Ref1inzcav, Ref1midzcav, Ref1outzcav, Ref10inzcav, Ref10midzcav and Ref10outzcav measured in the above (i) and (ii) should satisfy the following conditions.

｜ Ref1inzcav−Ref1outzcav ｜ ／Ref1midzcav≦0.05
｜ Ref10inzcav−Ref1inzcav | /Ref10inzcav≦0.05
｜ Ref10midzcav−Ref1midzcav | /Ref10midzcav≦0.05
｜ Ref10outzcav−Ref1outzcav | /Ref10outzcav≦0.05
[F] Of the two adjacent zones, the zone located on the inner circumference side is designated as zone A, and the zone located on the outer circumference side is designated as zone B. Further, the initialization focused light intensity in zone A is Pin, and the initialization focused light intensity in zone B is Pout. Further, the above-mentioned Pin and Pout, and the minimum initialization laser intensity PJmin and the maximum initialization laser intensity PJmax measured by the following method are PJmin ≦ Pin ≦ Pout ≦ PJmax,
The intensity of the focused light is set so as to satisfy And it is also preferable to comprise the control part 7 so that the intensity | strength of focused light may be controlled based on the said setting.
(Conditions to be satisfied by maximum initialization laser intensity PJmax and minimum initialization laser intensity PJmin)
J2zoneAout is a jitter value when recording is performed twice on one track in the vicinity of the outermost periphery in the zone A in the optical information recording medium, and the vicinity of the central portion in the zone A in the optical information recording medium. J10 zoneAmid is the jitter value when recording is performed 10 times on one track, and the jitter value when recording is performed twice on one track near the innermost circumference in the zone B of the optical information recording medium. When J2zoneBin
The J2zoneAout, the J2zoneBin, and the J10zoneAmid are
J2zoneAout / J10zoneAmid ≦ 1.6
J2zoneBin / J10zoneAmid ≦ 1.6
The minimum value of the laser intensity that satisfies the above is PJmin, and the maximum value of the laser intensity is PJmax.
[G] Further, of two adjacent zones, a zone located on the inner peripheral side is referred to as zone A, and a zone located on the outer peripheral side is referred to as zone B. Further, the initialization focused light intensity in zone A is Pin, and the initialization focused light intensity in zone B is Pout. Further, the above-mentioned Pin and Pout, and the minimum initialization laser intensity PRmin and the maximum initialization laser intensity PRmax measured by the following method are: PRmin ≦ Pin ≦ Pout ≦ PRmax
The intensity of the focused light is set so as to satisfy And it is also preferable to comprise the control part 7 so that the intensity | strength of focused light may be controlled based on the said setting.
(Conditions that the maximum initialization laser intensity PRmax and the minimum initialization laser intensity PRmin should satisfy)
The reflectance value when recording is performed once on one track near the outermost periphery of the zone A in the optical information recording medium is RefzoneAout, and the reflectance value is 1 near the center of the zone A in the optical information recording medium. The reflectance when recording is performed once on the track is RefzoneAmid, and the reflectance value when recording is performed once on one track near the innermost circumference of the zone B in the optical information recording medium is RefzoneBin. And when
｜ RefzoneAout−RefzoneBin ｜ /RefzoneAmid≦0.05
The minimum value of the laser intensity that satisfies the above is PRmin, and the maximum value of the laser intensity is PRmax.
[H] In addition, the initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, and the rotational speed at the innermost circumferential position in each zone is constant. The control unit 7 is preferably configured so that the scanning linear velocity is constant up to the outer periphery. When the control unit 7 performs initial crystallization of the recording layer, the control unit 7 controls the intensity of the focused light in each zone based on the intensity of the focused light in each zone set so as to satisfy the following conditions. It is also preferable to configure.
(I) In each zone in the recording area of the optical information recording medium obtained through the initial crystallization, recording is performed twice on one track near the center, and the jitter value J2midzclv after the second recording is measured. To do.
(Ii) Recording is further performed 8 times for one track near the center, and the jitter value J10midzclv after 10 times of recording is measured.
(Iii) The intensity of the focused light in each zone is set so that J2midzclv and J10midzclv measured in (i) and (ii) above satisfy the following conditions.

J2midzclv / J10midzclv ≦ 1.6
[I] Further, the initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, and the control unit 7 keeps the rotation speed at the innermost circumferential position in each zone constant. It is preferable that the scanning linear velocity is constant from the innermost circumference to the outermost circumference. Here, it is preferable to control the intensity of the focused light in each zone based on the intensity of the focused light in each zone set so as to satisfy the following conditions.
(I) In each zone in the recording area of the optical information recording medium obtained through the initial crystallization, recording is performed once per track near the center, and the reflectance value Ref1midzclv is measured.
(Ii) Recording is further performed 9 times on one track near the center, and the reflectance value Ref10midzclv after 10 recordings is measured.
(Iii) Ref1midzclv and Ref10midzclv measured in the above (i) and (ii) satisfy the following conditions.

｜ Ref10midzclv−Ref1midzclv | /Ref10midzclv≦0.05
[J] Further, a zone located on the inner peripheral side of two adjacent zones among the plurality of zones is referred to as zone A, and a zone located on the outer peripheral side is referred to as zone B. Further, the initialization focused light intensity in zone A is Pin, and the initialization focused light intensity in zone B is Pout. And it is also preferable to comprise the control part 7 so that the intensity | strength of focused light may be controlled based on the intensity | strength of focused light set so that the following conditions may be satisfy | filled.
(I) Two recording media are prepared. On one recording medium, zone A is initially crystallized with an initial focused light intensity Pin, and zone B is initially crystallized with an initial focused light intensity Pout to obtain an optical information recording medium. Then, recording is performed 10 times on one track near the center of the zone A of the optical information recording medium, and the jitter value J10zoneAPin after 10 times recording is measured, and on one track near the center of the zone B. The recording is performed 10 times, and the jitter value J10zoneBPout after the 10th recording is measured.
(Ii) In the other recording medium, the zone A is initially crystallized with the initialized focused light intensity Pout, and the zone B is initially crystallized with the initialized focused light intensity Pin to obtain an optical information recording medium. Then, recording is performed twice on one track near the center of zone A of the optical information recording medium, the jitter value J2zoneAPout after the second recording is measured, and on one track near the center of zone B. Perform recording twice and measure the jitter value J2zoneBPin after the second recording.
(Iii) J10zoneAPin and J2zoneAPout measured in (i) and (ii) above are
J2zoneAPout / J10zoneAPin ≦ 1.6
Meet the requirements of
J10zoneBPout and J2zoneBPin measured in (i) and (ii) above are
J2zoneBPin / J10zoneBPout ≦ 1.6
Meet the requirements of
[K] Further, in two adjacent zones among the plurality of zones, a zone located on the inner circumference side is designated as zone A, and a zone located on the outer circumference side is designated as zone B. Further, the initialization focused light intensity in zone A is Pin, and the initialization focused light intensity in zone B is Pout. And it is also preferable to comprise the control part 7 so that the intensity | strength of focused light may be controlled based on the intensity | strength of focused light set so that the following conditions may be satisfy | filled.
(I) Two recording media are prepared, and in one of the recording media, zones A and B are initially crystallized with the initializing focused light intensity Pin to obtain an optical information recording medium. Then, recording is performed once on one track near the center of zone A of the optical information recording medium, and the reflectance Ref1zoneAPin after one recording is measured, and on one track near the center of zone B. Record once and measure the reflectance Ref1zoneBPin after the first recording.
(Ii) In the other recording medium, the zone A is initially crystallized with the initializing focused light intensity Pout to obtain an optical information recording medium. Then, one recording is performed on one track near the center of the zone A of the optical information recording medium, and the reflectance Ref1zoneAPout after one recording is measured.
(Iii) Ref1zoneAPin, Ref1zoneBPin, and Ref1zoneAPout measured in (i) and (ii) above are
｜ Ref1zoneAPout−Ref1zoneBPin ｜ /Ref1zoneAPin≦0.05
To satisfy the relationship.
[L] Here, it is also preferable to configure the control unit 7 as follows. That is, the minimum value that can be taken by the focused light intensity Pin of the zone A is Pinmin, the maximum value is Pinmax, the minimum value that can be taken by the focused light intensity Pout of the zone B is Poutmin, and the maximum value is Poutmax. Furthermore, as it goes to the outer peripheral side in the zone A, the focused light intensity Pin is gradually increased within a range from Pinmin to Pinmax. The value of the focused light intensity Pin at the outermost periphery of the zone A is PinzoneAout. Similarly, the focused light intensity Pout is gradually increased in the range from Poutmin to Poutmax as it goes to the outer peripheral side in the zone B. The value of the focused light intensity Pout at the innermost circumference of the zone B is PoutzoneBin. Here, the relationship between PinoutBin and PinzoneAout is
PoutzoneBin ＝ PinzoneAout
It is also preferable to configure the control unit 7 so as to control the intensity of the focused light based on the intensity of the focused light set to be However, even if “PoutzoneBin = PinzoneAout”, an error of about ± 10% is allowed between PoutzoneBin and PinzoneAout.
[M] It is also preferable to configure the control unit 7 as follows. That is, the minimum value that can be taken by the focused light intensity Pin of the zone A is Pinmin, the maximum value is Pinmax, the minimum value that can be taken by the focused light intensity Pout of the zone B is Poutmin, and the maximum value is Poutmax. Furthermore, as it goes to the outer peripheral side in the zone A, the focused light intensity Pin is gradually increased within a range from Pinmin to Pinmax. The value of the focused light intensity Pin at the outermost periphery of the zone A is PinzoneAout. Similarly, the focused light intensity Pout is gradually increased in the range from Poutmin to Poutmax as it goes to the outer peripheral side in the zone B. The value of the focused light intensity Pout in the innermost circumference of the zone B is PoutzoneBin. Here, the relationship between PinoutBin and PinzoneAout is
PoutzoneBin> PinzoneAout
And set so that the difference between PinoutBin and PinzoneAout is minimized. The control unit 7 may be configured to control the intensity of the focused light based on the set intensity of the focused light.
[N] Further, the controller 7 sets the rotational speed R0 per unit time to be constant until it reaches a predetermined radial position from the innermost peripheral position of the initial crystallization region toward the outer peripheral side of the recording medium, It is also preferable that the scanning linear velocity is constant from the predetermined radial position to the outermost peripheral position of the initial crystallization region of the recording layer. The conditions to be satisfied by R0 are as described above.
[O] Here, it is preferable to set the maximum linear velocity Vmax at the predetermined radial position so as to satisfy the following condition.
(I) The recording layer formed on an arbitrary track in the initial crystallization region is initially crystallized at an arbitrary linear velocity.
(Ii) Recording is performed twice on the track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) The above (i) to (iv) are repeated while changing the linear velocity.
(Vi) The linear velocity that makes J2 / J10 obtained from the jitter values J2 and J10 obtained at the respective linear velocities 1.6 or less is the maximum linear velocity Vmax.
[P] It is also preferable that the maximum linear velocity used for initial crystallization of the recording layer is equal to or higher than the maximum linear velocity capable of erasing the amorphous mark on the optical information recording medium.
[Q] In the initialization apparatus of the present invention, the focused light is preferably laser light.
[R] Others The rotational speeds of the above [C] to [M] and [O], the intensity of the focused light, and the linear velocity at a predetermined radial position are set in advance before the initial crystallization step. The results are stored in the memory of the control unit 7 and read out from the memory in the initial crystallization process to control the rotational speed of the spindle motor, control the intensity of the focused light (preferably laser light), and scan. The speed of the line may be controlled.

  In the initial crystallization step, the setting of the rotational speeds of [C] to [M], [O], and [P], the setting of the intensity of the focused light, and the setting of the linear velocity at a predetermined radial position are, for example, The following method is used. That is, the setting of the rotational speed and the like is performed by another device such as an evaluation device, and the result is input to the initialization device. Based on this, the control unit 7 may perform the rotation speed control of the spindle motor, the intensity control of the focused light (laser light), and the speed control of the scanning line. Moreover, as another method, the following method can also be mentioned, for example. That is, the rotation speeds of the above [C] to [M] and [O], the intensity of the focused light, and the linear velocity at the predetermined radial position set by other apparatuses such as an evaluation apparatus are sent to the initialization apparatus. Configure. And based on this, the control part 7 can also be made to perform rotation speed control of a spindle motor, intensity | strength control of focused light (laser light), and speed control of a scanning line. In this case, the initial crystallization process is automatically performed by linking the initialization apparatus with another apparatus such as an evaluation apparatus.

Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
Example 1
(A) Step of obtaining recording medium As the substrate, a disc-shaped polycarbonate substrate having the following shape was used.

Track pitch: 0.74 μm
Groove width: 0.32 μm
Groove depth: 32 nm
Track shape: Spiral thickness: 0.6mm
On this substrate, a 60 nm (ZnS) ₈₀ (SiO ₂ ) ₂₀ protective layer, 2 nm Y ₂ O ₂ S layer, 12 nm Ge _4.7 In _10.1 Sb _50.1 Sn _21.2 Te _13.9 recording by sputtering using Ar gas. A 14 nm Y ₂ O ₂ S layer, a 2 nm Ta interface layer, a 200 nm Ag reflecting layer, and an about 4 μm UV-curing resin layer were formed in this order. The Ta layer is an interface layer for preventing diffusion of S into the Ag reflection layer.

Each layer was laminated on the substrate by sputtering in order without releasing the vacuum. However, the ultraviolet curable resin layer was applied by spin coating. Thereafter, a similar 0.6 mm thick substrate, which was not formed, was bonded with an adhesive so that the recording layer surface was on the inside to form a 1.2 mm thick disc (recording medium).
This recording medium has a composition and a layer so that overwriting can be performed up to about 8 to 10 times the standard linear velocity of 3.49 m / s (1 × speed) when the rewritable DVD is used after the initial crystallization process. The configuration is chosen. That is, the upper limit of the linear velocity at which the erasing ratio is 20 dB or more when the erasing power is applied in a direct current is 8 to 10 times faster.

In this example, a plurality of such recording media were prepared and initialized under various initialization conditions, and the performance of the obtained optical information recording medium was evaluated.
(B) Initialization process The following initialization conditions and initialization methods were used.
<Initialization conditions>
An elliptical laser beam having a wavelength of 810 nm, a major axis of about 75 μm, and a minor axis of about 1 μm was used as the focused light. The laser beam intensity at the initial step was changed within a range of 1000 to 4000 mW. The maximum rotation speed of the initialization device used was 8200 rpm.
<Initialization method>
CAV initialization For a recording medium divided into a plurality of zones in the radial direction, the rotational speed is constant (R0) from the inner periphery to the outer periphery, and the feed amount per rotation of the disk of the laser head is 50 μm for each zone. As a result, initialization was performed by changing the laser intensity between 1200 and 3600 mW.

ZCLV initialization For the recording medium divided into a plurality of zones in the radial direction, the rotational speed of the innermost circumference in each zone was made constant at R0. The linear velocity in each zone was constant. Initialization was performed by changing the laser intensity between 1200 to 3600 mW with a feed amount per one rotation of the laser head of 50 μm for each zone.

Note that the scanning linear velocity V (m / s) at the time of initialization is R0 (rpm) as the disk rotation speed and r (mm) as the radial position to be initialized.
V (m / s) = (R0 / 60) × 2 × 3.14 × (r / 1000)
It can be calculated with
As a specific example, in the conditions given in the following examples,
At 5000 rpm and 23 mm, 12.3 m / s
At 8200 rpm and 23 mm, 19.7 m / s
15.0 m / s at 8200 rpm and 35 mm
At 8200 rpm and 40 mm, 34.3 m / s
At 8200 rpm and 43 mm, 36.9 m / s
41.2 m / s at 8200 rpm and 48 mm
At 8200 rpm and 50 mm, 42.9 m / s
At 8200 rpm and 58 mm, 49.8 m / s
It becomes. In the case of 8200 rpm, outside the radius of about 40 mm, the speed is almost 10 times the DVD standard linear velocity or more. As will be described later, when the present recording medium is initialized at a linear velocity of 10 times or higher than that of DVD, good recording characteristics can be obtained.
(C) Evaluation method of optical information recording medium <Evaluation apparatus>
Device name: ODU1000 (Pulstec)
Focused light: Laser light having a wavelength of 650 nm and NA = 0.65 <Evaluation method>
The reference linear velocity is set to 3.49 m / s which is the reference linear velocity of DVD, the reference clock frequency is set to 26.2 MHz (clock cycle T _s = 38.2 ns), and the EFM + modulated signal is recorded at 8 × speed. Clock jitter was measured at speed.

  Here, the clock jitter is a value obtained as follows. That is, the reproduction signal is passed through the equalizer and the LPF, and then converted into a binary signal by the slicer. Then, a standard deviation (jitter) of a time lag with respect to the PLL clock of the leading edge and trailing edge of the binarized signal is obtained. Further, the standard deviation obtained by normalizing with the clock period: T is defined as clock jitter.

The reflectance value was determined as follows. That is, the recording waveform recorded by the above method is output to an oscilloscope. Then, at the reference linear velocity, the average value of the maximum value of the 14T signal amplitude was directly read from the oscilloscope to obtain the reflectance value.
(D) Determination of maximum rotation speed (Rmax, R0) The rotation speed R0 of the initialization apparatus was set to 5000 rpm, and CAV initialization was performed on the recording medium. Then, the jitter value (J2) after the second recording in the track having a radius of 23 mm of the obtained optical information recording medium (the innermost track of the recording area in the initial crystallization area where the initial crystallization of the recording medium is performed). ) The jitter value (J10) after 10 recordings was measured.

J2 = Dow1jitter = 15.19%
J10 = Dow10jitter = 8.26%
J2 / J10 = 1.84
Next, another recording medium was prepared, and CAV initialization was performed on this recording medium with the rotation speed R0 of the initialization apparatus set to 8200 rpm (maximum rotation speed of the initialization apparatus). Then, the jitter value (J2) after the second recording in the track having a radius of 23 mm of the obtained optical information recording medium (the innermost track of the recording area in the initial crystallization area where the initial crystallization of the recording medium is performed). ) The jitter value (J10) after 10 recordings was measured.

J2 = Dow1jitter = 11.07%
J10 = Dow10jitter = 8.22%
J2 / J10 = 1.35
In the initialization apparatus used in this example, the rotational speed could not be made faster than 8200 rpm. However, if CAV initialization is performed at a rotational speed faster than 8200 rpm, J2 / J10 May be small (the recording characteristics of the optical information recording medium will be good). However, considering the recording quality in actual use, it is sufficient that J2 / J10 is 1.6 or less. Therefore, in the present invention, 8200 rpm is set as the maximum rotational speed Rmax (R0).
(E) Setting of initialization laser intensity in ZCAV zone (setting by jitter value)
Nine recording media were prepared, and CAV initialization was performed with different initialization laser intensities for the respective recording media under the condition of the rotational speed R0 of the initialization device: 8200 rpm. Here, the initialization laser intensity was changed at 1200 to 3600 mW.

A position having a radius of 40 to 50 mm in the obtained nine optical information recording media (recording media initialized under different initialization conditions with different initialization laser intensities) was defined as one zone. And in this zone,
Jitter value J2inzcav after two recordings on one track near the innermost circumference
Jitter value J2outzcav after recording twice in one track near the outermost circumference
Jitter value after recording twice in one track near the center J2midzcav
Was measured.

Further, 8 times of recording (total of 10 times of recording) was performed on one track near the center portion, and the jitter value J10midzcav after 10 times of recording was measured.
And in each optical information recording medium,
J2inzcav / J10midzcav
J2midzcav / J10midzcav
J2outzcav / J10midzcav
Was calculated.

  The relationship between the calculation result thus obtained and the initialization laser intensity is shown in FIG. In the figure, the experimental result indicated by “inner” indicates a change of “J2inzcav / J10midzcav” with respect to the initialization laser intensity. In addition, the experimental result indicated by “middle” in the figure shows the change of “J2midzcav / J10midzcav” with respect to the initialization laser intensity. Similarly, the experimental result indicated by “outer” in the same figure shows the change of “J2outzcav / J10midzcav” with respect to the initialization laser intensity.

From the results in the figure, if the initialization laser intensity is set to 1500 to 3000 mW,
J2inzcav / J10midzcav ≦ 1.6
J2midzcav / J10midzcav ≦ 1.6
J2outzcav / J10midzcav ≦ 1.6
It can be seen that is surely satisfied. Furthermore, if the initialization laser intensity is set to 1800-2400 mW,
J2inzcav / J10midzcav ≦ 1.3
J2midzcav / J10midzcav ≦ 1.3
J2outzcav / J10midzcav ≦ 1.3
It can be seen that is surely satisfied.
(F) Setting of initialization laser intensity in ZCAV zone (setting by reflectance value)
Nine recording media were prepared, and CAV initialization was performed with different initialization laser intensities for the respective recording media under the condition of the rotational speed R0 of the initialization device: 8200 rpm. Here, the initialization laser intensity was changed at 1200 to 3600 mW.

A position having a radius of 40 to 50 mm in the obtained nine optical information recording media (recording media initialized under different initialization conditions with different initialization laser intensities) was defined as one zone. And in this zone,
Reflection value Ref1inzcav of one track near the innermost track after one recording
Reflectance value Ref1midzcav of one track near the center
Reflectance value Ref1outzcav of one track near the outermost circumference
After measuring 9 times (recording 10 times in total) on each track,
Reflectance value of one track near the innermost circumference Ref10inzcav
Reflectance value of one track near the center Ref10midzcav
Reflectivity value of one track near the outermost circumference Ref10outzcav
Was measured respectively.

And in each optical information recording medium,
｜ Ref1inzcav−Ref1outzcav ｜ / Ref1midzcav
Was calculated. The relationship between the calculation result thus obtained and the initialization laser intensity is shown in FIG.
From the results in the figure, if the initialization laser intensity is set to 1800-3300 mW,
｜ Ref1inzcav−Ref1outzcav ｜ ／Ref1midzcav≦0.05
It can be seen that is surely satisfied. Furthermore, if the initialization laser intensity is set to 1800-2400 mW,
｜ Ref1inzcav−Ref1outzcav ｜ ／Ref1midzcav≦0.03
It can be seen that is surely satisfied.

Furthermore, in each optical information recording medium,
｜ Ref10inzcav−Ref1inzcav | / Ref10inzcav
｜ Ref10midzcav−Ref1midzcav | / Ref10midzcav
｜ Ref10outzcav−Ref1outzcav | / Ref10outzcav
Was calculated. FIG. 19 shows the relationship between the calculation result thus obtained and the initialization laser intensity. In the figure, the experimental result indicated by “inner” indicates the change of “| Ref10inzcav−Ref1inzcav | / Ref10inzcav” with respect to the initialization laser intensity. In addition, the experimental result indicated by “middle” in the figure shows a change of “| Ref10midzcav−Ref1midzcav | / Ref10midzcav” with respect to the initialization laser intensity. Similarly, the experimental result indicated by “outer” in the same figure shows the change of “| Ref10outzcav−Ref1outzcav | / Ref10outzcav” with respect to the initialization laser intensity.

From the results shown in the figure, if the initialization laser intensity is set to 2100-3600 mW,
｜ Ref10inzcav−Ref1inzcav | /Ref10inzcav≦0.05
｜ Ref10midzcav−Ref1midzcav | /Ref10midzcav≦0.05
｜ Ref10outzcav−Ref1outzcav | /Ref10outzcav≦0.05
It can be seen that is surely satisfied.
(G) Setting of initialization laser intensity between zones in ZCAV (setting by jitter value and reflectance value)
(G-1) Setting by Jitter Value Nine recording media are prepared, and CAV initialization is performed with different initialization laser intensities for the respective recording media under the condition of the rotation speed of the initialization device R0: 8200 rpm. It was. At the time of initialization, the position of radius 40 to 50 mm of the recording medium was set as zone A, and the position of radius 50 to 58 mm was set as zone B. Then, the initialization laser intensity Pin in the zone A and the initialization laser intensity Pout in the zone B were changed between 1200 to 3600 mW so as to be different for each recording medium.

In each of the nine obtained optical information recording media,
Jitter value J2zoneAout when recording twice on one track near the outermost circumference in zone A
Jitter value J10zoneAmid when recording 10 times on one track near the center in Zone A,
Jitter value J2zoneBin when recording twice on one track near the innermost circumference in zone B,
Was measured respectively.

And in each optical information recording medium,
J2zoneAout / J10zoneAmid
J2zoneBin / J10zoneAmid
Was calculated. The relationship between the calculation result thus obtained and the initialization laser intensity is shown in FIG.

The experimental result indicated by “z-aout” in the same figure shows the change of “J2zoneAout / J10zoneAmid” with respect to the initialization laser intensity. Similarly, the experimental result indicated by “z-bin” in the figure shows the change of “J2zoneBin / J10zoneAmid” with respect to the initialization laser intensity.
From the results in the figure,
J2zoneAout / J10zoneAmid ≦ 1.6
J2zoneBin / J10zoneAmid ≦ 1.6
It can be seen that PJmin that satisfies the above is 1500 mW. And it turns out that PJmax which satisfy | fills the said conditions reliably is 3600 mW.

Furthermore, from the results in the figure,
J2zoneAout / J10zoneAmid ≦ 1.3
J2zoneBin / J10zoneAmid ≦ 1.3
It can be seen that PJmin that satisfies the above is 1800 mW. And it turns out that PJmax which satisfy | fills the said conditions reliably is 2700 mW.

From the above results, the initialization laser intensity Pin of the zone A and the initialization laser intensity Pout of the zone B are expressed as Pin ≦ Pout between PJmin (1500 mW, preferably 1800 mW) and PJmax (3600 mW, preferably 2700 mW). It can be seen that the recording quality of the optical information recording medium in the vicinity of the boundary between zone A and zone B is good.
(G-2) Setting by reflectance value Nine recording media are prepared, and CAV initialization is performed with different initialization laser intensities for each recording medium under the condition of the rotation speed of the initialization device R0: 8200 rpm. went. At the time of initialization, the position of radius 40 to 50 mm of the recording medium was set as zone A. Then, the position of radius 50 to 58 mm was set as zone B, and the initialization laser intensity Pin in zone A and the initialization laser intensity Pout in zone B were varied between 1200 to 3600 mW depending on the recording medium.

In each of the nine obtained optical information recording media,
Reflectance value RefzoneAout when recording is performed once on one track near the outermost periphery in zone A,
Reflectance value RefzoneAmid when recording is performed once on one track near the center in Zone A,
Reflectance value RefzoneBin when recording is performed once on one track near the innermost circumference in Zone B,
Was measured respectively.

And in each optical information recording medium, Pin ≦ Pout,
| RefzoneAout−RefzoneBin | / RefzoneAmid
Was calculated. The relationship between the calculation result thus obtained and the initialization laser intensity is shown in FIG.
The experimental result indicated by “Pin = Pout” in the same figure shows the change of “| RefzoneAout−RefzoneBin | / RefzoneAmid” when the initialization laser intensity is equal in each zone. Similarly, in the same figure, for example, the experimental result indicated by “Pin <Pout 3.6” indicates that the initialization laser intensity in zone B is 3600 mW, and the initialization laser intensity is less than Pin. It shows the change of “| RefzoneAout−RefzoneBin | / RefzoneAmid”.

From the results in the figure, when Pin = Pout, all initialization laser intensities of 1200 to 3600 mW are obtained.
| RefzoneAout−RefzoneBin | /RefzoneAmid≦0.05
It can be seen that is surely satisfied.
If Pin <Pout,
| RefzoneAout−RefzoneBin | /RefzoneAmid≦0.05
It can be seen that PRmin satisfying the above is 2100 mW or more.

Furthermore, from the results in the figure,
| RefzoneAout−RefzoneBin | /RefzoneAmid≦0.03
It can be seen that PRmin satisfying the above is 3000 mW or more.
In addition, from the result of the figure, it is considered that PRmax exists at 3600 mW or more. However, here, it is assumed that PRmax is 3600 mW.

From the above results, the initialization laser intensity Pin of the zone A and the initialization laser intensity Pout of the zone B are set to Pin = Pout, or PRmin (2100 mW, preferably 3000 mW) and PRmax (3600 mW). On the other hand, it can be seen that when PRmin ≦ Pin ≦ Pout ≦ PRmax, the recording quality of the optical information recording medium in the vicinity of the boundary between zone A and zone B is improved.
(H) ZCLV, setting of initialization laser intensity in zone (setting by jitter value and reflectance value)
Nine recording media were prepared, and ZCLV initialization was performed with different initialization laser intensities for the respective recording media under the condition of the rotation speed of the initialization device R0: 8200 rpm. Specific initialization conditions are as follows.

  A radius of 35 to 43 mm of the recording medium was set as zone A, and a radius of 43 to 48 mm was set as zone B. The scanning line speed when initializing the zone A was 30 m / s, and the scanning line speed when initializing the zone B was 37 m / s. By setting this scanning line speed, the rotational speed at the innermost circumference of zone A is 8200 rpm, the rotational speed at the innermost circumference of zone B is also 8200 rpm, and the rotational speed at the innermost circumferential position of each zone is constant. It becomes.

In the state where the scanning linear velocities in the zones A and B of the nine recording media prepared are set as described above, the initialization of the respective recording media is performed at different initialization laser intensities between 1200 to 3600 mW. I made it.
In each optical information recording medium obtained in this way, the reflectivity (Ref1midzclv) after one recording near the center of each zone,
Jitter value after recording twice (J2midzclv),
Jitter value after 10 recordings (J10midzclv)
Reflectance after 10 recordings (Ref10midzclv)
Was measured respectively.

And among the obtained data, in each optical information recording medium,
J2midzclv / J10midzclv
｜ Ref10midzclv−Ref1midzclv | / Ref10midzclv
Was calculated respectively. The relationship between the calculation result thus obtained and the initialization laser intensity is shown in FIGS.

From the results of FIG.
J2midzclv / J10midzclv ≦ 1.6
It can be seen that the initialization laser intensity that reliably satisfies the above conditions is in the range of 1200 to 3300 mW in zone A, and in the range of 1500 to 3600 mW in zone B. further,
J2midzclv / J10midzclv ≦ 1.3
It can be seen that the initialization laser intensity that reliably satisfies the above conditions is in the range of 1200 to 2100 mW in the zone A and in the range of 1500 to 2400 mW in the zone B.

Moreover, from the result of FIG.
｜ Ref10midzclv−Ref1midzclv | /Ref10midzclv≦0.05
It can be seen that the initialization laser intensity that reliably satisfies the above condition is in the range of 1500 to 3600 mW in zone A and 1800 to 3600 mW in zone B. further,
｜ Ref10midzclv−Ref1midzclv | /Ref10midzclv≦0.03
It can be seen that the initialization laser intensity that reliably satisfies the above condition is in the range of 1500 to 3000 mW in the zone A and 2100 to 3600 mW in the zone B.

From the results shown in FIGS. 21 and 22, the optimum initialization laser intensity in zone A (a value that can reduce the reflectance ratio while reducing the jitter ratio) can be estimated to be 1500 mW. Similarly, the optimum initialization laser intensity in zone B (a value that can reduce the reflectance ratio while reducing the jitter ratio) can be estimated to be 2100 mW.
(I) ZCLV, setting of initialization laser intensity between zones (setting by jitter value)
Next, in each optical information recording medium,
Jitter value after two recordings near the center of zone A when the laser intensity is changed (hereinafter referred to as J2zoneA) / J10zoneAPin,
Jitter value after two recordings near the center of Zone B when the laser intensity is changed (hereinafter referred to as J2zoneB) / J10zoneBPout
Was calculated. Here, J10zoneAPin used the jitter value after 10 times of recording when zone A is initialized with an initialization laser intensity of 1500 mW (1500 mW is assumed to be Pin ′, which is a temporary Pin). J10zoneBPout used a jitter value after 10 times of recording when zone B was initialized with an initialization laser intensity of 2100 mW (2100 mW is assumed to be Pout ′, which is a temporary Pout). FIG. 23 shows the relationship between the calculation result thus obtained and the initialization laser intensity.

In the figure, “zoneA” indicates the value of “J2zoneA / J10zoneAPin”, and “zoneB” indicates “J2zoneB / J10zoneBPout”.
From the results in the figure,
J2zoneA / J10zoneAPin ≦ 1.6
J2zoneB / J10zoneBPout ≦ 1.6
It can be seen that the initialization laser intensity that satisfies the above is in the range of 1500 to 2400 mW. That is, even if zone A is initialized with Pout ′ (2100 mW) or zone B is initialized with Pin ′ (1500 mW), J2zoneA / J10zoneAPin ≦ 1.6 and J2zoneB / J10zoneBPout ≦ 1.6 can be achieved. it can.

From the results in the figure,
J2zoneA / J10zoneAPin ≦ 1.3
J2zoneB / J10zoneBPout ≦ 1.3
It can be seen that the initialization laser intensity that satisfies the above is in the range of 1500 to 1800 mW. In this case, Pout ′ (2100 mW) is a value larger than 1800 mW. Therefore, it can be considered that setting Pout to 1800 mW makes it easier to balance the characteristics after initialization of zones A and B.
(J) ZCLV, setting of initialization laser intensity between zones (setting by reflectivity value)
Further, in each optical information recording medium, the reflectivity value after one recording near the center of zone A when the laser intensity is changed (referred to herein as Ref1zoneA) and the laser intensity are changed. The reflectivity value after recording once in the vicinity of the center of zone B (referred to herein as Ref1zoneB) was measured. Then, | Ref1zoneA−Ref1zoneB | / Ref1zoneAPin was calculated.

  Here, when the zone A was initialized with 1500 mW and 1800 mW obtained above as Pin ′, the reflectance after one-time recording was defined as Ref1zoneAPin. The relationship between the calculation result thus obtained and the initialization laser intensity is shown in FIG. In the figure, “Pin 1500” indicates | Ref1zoneA−Ref1zoneB | / Ref1zoneAPin when Ref1zoneAPin at Pin ′ = 1500 mW is used. Similarly, in the figure, “Pin 1800” indicates | Ref1zoneA−Ref1zoneB | / Ref1zoneAPin when Ref1zoneAPin at Pin ′ = 1800 mW is used. In the figure, “| zone A reflectivity after one recording—zone B reflectivity after one recording” represents | Ref1zoneA−Ref1zoneB |.

From the results shown in the figure, when Pin ′ is 1500 mW,
｜ Ref1zoneA−Ref1zoneB ｜ /Ref1zoneAPin≦0.05
It can be seen that the initialization laser intensity that satisfies the above condition is in the range of 1200 to 1500 mW. That is, when the laser intensity of the zone A is 1500 mW, it can be understood that the zone B may be initialized within the range of 1200 to 1500 mW.

On the other hand, when Pin ′ is 1800 mW,
｜ Ref1zoneA−Ref1zoneB ｜ /Ref1zoneAPin≦0.05
It can be seen that the initialization laser intensity that satisfies the above is in the range of 1500 to 2400 mW. That is, when the laser intensity of the zone A is 1800 mW, it can be understood that the zone B may be initialized in the range of 1500 to 2400 mW.

Furthermore, from the results shown in the figure, when Pin ′ is 1500 mW,
｜ Ref1zoneA−Ref1zoneB ｜ /Ref1zoneAPin≦0.03
It can be seen that the initialization laser intensity that satisfies the above is 1200 mW. That is, when the laser intensity in zone A is 1500 mW, it can be seen that zone B may be initialized at 1200 mW.

On the other hand, when Pin ′ is 1800 mW,
｜ Ref1zoneA−Ref1zoneB ｜ /Ref1zoneAPin≦0.03
It can be seen that the initialization laser intensity that satisfies the above condition is in the range of 1500 to 2100 mW. That is, when the laser intensity in zone A is 1800 mW, zone B may be initialized in the range of 1500 to 2100 mW.

Here, when the laser intensity in zone A is 1500 mW, zone A> zone B. For this reason, it is presumed that it is preferable to set the laser intensity of zone A to 1800 mW and the laser intensity of zone B to 1800 to 2100 mW.
(Example 2)
(A) Step of obtaining recording medium As the substrate, a disc-shaped polycarbonate substrate having the following shape was used.

Track pitch: 0.74 μm
Groove width: 0.32 μm
Groove depth: 32 nm
Track shape: Spiral thickness: 0.6mm
On this substrate, a 60 nm (ZnS) ₈₀ (SiO ₂ ) ₂₀ protective layer, 2 nm Y ₂ O ₂ S layer, 12 nm Ge _4.7 In _10.1 Sb _50.1 Sn _21.2 Te _13.9 recording by sputtering using Ar gas. A 14 nm Y ₂ O ₂ S layer, a 2 nm Ta interface layer, a 200 nm Ag reflection layer, and a UV curable resin layer of about 4 μm were formed in this order. The Ta layer is an interface layer for preventing diffusion of S into the Ag reflection layer.

Each layer was laminated on the substrate by sputtering in order without releasing the vacuum. However, the ultraviolet curable resin layer was applied by spin coating. Thereafter, a similar 0.6 mm thick substrate, which was not formed, was bonded with an adhesive so that the recording layer surface was on the inside to form a 1.2 mm thick disc (recording medium).
This recording medium has a composition and a layer so that overwriting can be performed up to about 8 to 10 times the standard linear velocity of 3.49 m / s (1 × speed) when the rewritable DVD is used after the initial crystallization process. The configuration is chosen. That is, the upper limit of the linear velocity at which the erasing ratio is 20 dB or more when the erasing power is applied in a direct current is 8 to 10 times faster.

In this example, a plurality of such recording media were prepared and initialized under various initialization conditions, and the performance of the obtained optical information recording medium was evaluated.
(B) Initialization process The following initialization conditions and initialization methods were used.
<Initialization conditions>
An elliptical laser beam having a wavelength of 810 nm, a major axis of about 75 μm, and a minor axis of about 1 μm was used as the focused light. The laser beam intensity at the initial step was changed within a range of 1000 to 4000 mW. The maximum rotation speed of the initialization device used was 8200 rpm.
<Initialization method>
P-CAV initialization The zone on the inner circumference side starting from the innermost circumference is set to a constant rotation speed (R0 = 8200 rpm), and the zone on the outer circumference side from the radius at which the linear velocity reaches 30 m / s is initialized to the constant linear velocity. Carried out.

Note that the scanning linear velocity V (m / s) at the time of initialization is R0 (rpm) as the disk rotation speed and r (mm) as the radial position to be initialized.
V (m / s) = (R0 / 60) × 2 × 3.14 × (r / 1000)
It can be calculated with
The specific initialization linear velocity at each radius of this P-CAV initialization is:
23mm 8200rpm 19.7m / s
30mm 8200rpm 25.7m / s
35mm 8200rpm 30.0m / s
40mm 7166rpm 30.0m / s
50mm 5732rpm 30.0m / s
58mm 4942rpm 30.0m / s
It becomes.

Here, the relationship between each radial position and the initialization linear velocity is shown in FIG. In FIG. 26, “CLV” indicates the linear velocity at each radial position, and “CAV” indicates the number of rotations per unit time at each radial position.
(C) Evaluation method of optical information recording medium <Evaluation apparatus>
Device name: ODU1000 (Pulstec)
Focused light: Laser light having a wavelength of 650 nm and NA = 0.65 <Evaluation method>
The reference linear velocity is 3.49 m / s, which is the reference linear velocity of DVD, the reference clock frequency is 26.2 MHz (clock cycle T _s = 38.2 ns), and EFM + modulated signals are recorded at 6 × and 8 × linear speeds. After that, the clock jitter was measured at the reference linear velocity.

  Here, the clock jitter is a value obtained as follows. That is, the reproduction signal is passed through the equalizer and the LPF, and then converted into a binary signal by the slicer. Then, a standard deviation (jitter) of a time lag with respect to the PLL clock of the leading edge and trailing edge of the binarized signal is obtained. Further, the standard deviation obtained by normalizing with the clock period: T is defined as clock jitter.

The reflectance value was determined as follows. That is, the recording waveform recorded by the above method is output to an oscilloscope. Then, at the reference linear velocity, the average value of the maximum value of the 14T signal amplitude was directly read from the oscilloscope to obtain the reflectance.
(D) Determination of Initialization Conditions Initialization conditions were determined as follows using the same method as in Example 1.

Maximum speed R0 = 8200rpm
Initialization power CAV area 1300-1900mW
CLV area 1900mW
In the CAV region, the initialization power was changed to be approximately proportional to the initialization linear velocity between 1300 mW and 1900 mW.
(E) Measurement of jitter value for P-CAV initialization After the recording medium is initialized under the initialization conditions, recording is performed twice and ten times at 8 times speed at each radial position from 23 mm to 58 mm of the radial position. The jitter value was measured. And J2 / J10 was calculated | required.

Further, in an actual commercial drive (drive that is actually sold in the market), it is not possible to carry out 8 × speed recording from the innermost circumference of the recording medium due to the limitation of the rotational speed. For this reason, the jitter values of the two-time recording and the ten-time recording were measured at a speed of 6 times at the positions of 23, 30, and 35 mm among the radii. And J2 / J10 was calculated | required.
Here, the relationship between the radial position and J2 / J10 is shown in FIG. From the results shown in FIG. 6, J2 / J10 at the time of 8 × speed recording in all the radial regions under the P-CAV initialization condition of this setting and at the time of 6 × speed recording at 23, 30 and 35 mm is J2 / J10 ≦ 1. .3 is satisfied.

It is a schematic diagram for demonstrating the light spot of the laser beam (focused light) used in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. (A)-(e) are the relationship between the scanning linear velocity of the laser beam (focusing light) and the radial position of a recording medium in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. It is a schematic diagram which shows. (A)-(d) shows the relationship between the initialization power of a laser beam (focusing light) and the scanning linear velocity in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. It is a schematic diagram. (A)-(c) is the relationship between the scanning linear velocity of the laser beam (focusing light) and the radial position of a recording medium in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. It is a schematic diagram which shows. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating a recording medium that is initially crystallized in an initialization step of a method for manufacturing an optical information recording medium according to an embodiment of the present invention, where (a) is a perspective view thereof, and (b) is ( It is AA 'arrow sectional drawing of a). It is a conceptual diagram which shows the relationship between the rotation speed R0 and J2 / J10 in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. (A), (b) is a schematic diagram which shows the setting example of the initialization laser intensity | strength of each zone in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating a recording medium that is initially crystallized in an initialization step of a method for manufacturing an optical information recording medium according to an embodiment of the present invention, where (a) is a perspective view thereof, and (b) is ( It is AA 'arrow sectional drawing of a). 1 is a schematic cross-sectional view showing a recording medium that is initially crystallized in an initialization step of a method for manufacturing an optical information recording medium according to an embodiment of the present invention. 1 is a schematic cross-sectional view showing a recording medium that is initially crystallized in an initialization step of a method for manufacturing an optical information recording medium according to an embodiment of the present invention. (A), (b) is a conceptual diagram for demonstrating the setting method of the initialization laser intensity | strength in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. (A), (b) is a schematic diagram for demonstrating the relationship between the scanning linear velocity and the radial position of a recording medium in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. It is. 1 is a schematic cross-sectional view showing a recording medium that is initially crystallized in an initialization step of a method for manufacturing an optical information recording medium according to an embodiment of the present invention. It is a conceptual diagram for demonstrating the setting method of the initialization laser intensity | strength in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. It is a conceptual diagram for demonstrating the setting method of the initialization laser intensity | strength in the initialization process of the manufacturing method of the optical information recording medium concerning one Embodiment of this invention. It is a schematic diagram which shows the structure of the initialization apparatus concerning one Embodiment of this invention. It is a figure for demonstrating the example of a setting of the initialization laser intensity | strength concerning one Example of this invention. It is a figure for demonstrating the example of a setting of the initialization laser intensity | strength concerning one Example of this invention. It is a figure for demonstrating the example of a setting of the initialization laser intensity | strength concerning one Example of this invention. It is a figure for demonstrating the example of a setting of the initialization laser intensity | strength concerning one Example of this invention. It is a figure for demonstrating the example of a setting of the initialization laser intensity | strength concerning one Example of this invention. It is a figure for demonstrating the example of a setting of the initialization laser intensity | strength concerning one Example of this invention. It is a figure for demonstrating the example of a setting of the initialization laser intensity | strength concerning one Example of this invention. It is a figure for demonstrating the example of a setting of the initialization laser intensity | strength concerning one Example of this invention. It is a figure for demonstrating the example of a setting of the initialization laser intensity | strength concerning one Example of this invention. It is a figure which shows the relationship between the initialization linear velocity of the recording medium concerning one Example of this invention, and the radial position of a recording medium. It is a figure which shows the optical recording characteristic in the radial position of the optical information recording medium concerning one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Initialization apparatus 2 Recording medium 3 Spindle motor 4 Motor driver 5 Initialization head (laser head)
6 Initialization head driver 7 Control unit

Claims (19)

A method of manufacturing an optical information recording medium having a phase change recording layer on a disk-shaped substrate,
Obtaining a recording medium on which the recording layer is formed;
An initial crystallization step of initial crystallization of the recording layer by scanning a light spot formed by irradiating the recording layer with focused light in a circumferential direction of the recording medium,
In the initial crystallization step, the scanning line speed when the light spot is scanned in the circumferential direction is increased toward the outer peripheral portion of the recording medium, and the intensity of the focused light is increased as the scanning line speed increases. In the case of initial crystallization of the entire crystallization region ,
The rotational speed R0 per unit time of the recording medium is made constant ,
The method of manufacturing an optical information recording medium, wherein the rotational speed R0 is set so as to satisfy the following condition.
(I) A plurality of recording media are prepared, and one of the recording media is rotated at an arbitrary number of revolutions, and at least the recording layer formed on the innermost track of the recording area of the recording medium is initially crystallized. Turn into.
(Ii) Recording is performed twice on the innermost track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) After initial crystallization is performed on another recording medium at a rotational speed different from the rotational speed of (i), the above (ii) to (iv) are performed.
(Vi) The operation of (v) is repeated while changing the recording medium.
(Vii) The relationship between J2 / J10 obtained from the jitter values J2 and J10 obtained from the recording medium initially crystallized at each rotational speed and the rotational speed at the time of initial crystallization is obtained. And R0 is set to the rotation speed which makes J2 / J10 1.6 or less. A method of manufacturing an optical information recording medium having a phase change recording layer on a disk-shaped substrate,
Obtaining a recording medium on which the recording layer is formed;
An initial crystallization step of initial crystallization of the recording layer by scanning a light spot formed by irradiating the recording layer with focused light in a circumferential direction of the recording medium,
In the initial crystallization step, in the case of initial crystallization of the entire surface of the initial crystallized region and greater as the outer peripheral portion of the recording medium scanning linear velocity at the time of scanning the light spot in the circumferential direction,
The initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, the intensity of the focused light irradiated in each zone is made constant, and the intensity of the focused light is increased in the zone on the outer peripheral side of the recording medium. A method of manufacturing an optical information recording medium. 3. The method of manufacturing an optical information recording medium according to claim 2 , wherein, in the initial crystallization step, the number of rotations R0 per unit time of the recording medium is made constant. A method of manufacturing an optical information recording medium having a phase change recording layer on a disk-shaped substrate,
Obtaining a recording medium on which the recording layer is formed;
An initial crystallization step of initial crystallization of the recording layer by scanning a light spot formed by irradiating the recording layer with focused light in a circumferential direction of the recording medium,
In the initial crystallization step, the scanning line speed when the light spot is scanned in the circumferential direction is increased toward the outer peripheral portion of the recording medium, and the intensity of the focused light is increased as the scanning line speed increases. In the case of initial crystallization of the entire crystallization region ,
The initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, and the number of revolutions at the innermost circumference position in each zone is constant, and the scanning is performed from the innermost circumference to the outermost circumference in each zone. A method for producing an optical information recording medium, characterized in that the linear velocity is constant. In the initial crystallization step before SL and constant intensity of the focused beam to be irradiated in each zone, the optical of claim 4, characterized in that to increase the strength of the outer peripheral side of the zone as the focused beam of the recording medium A method for manufacturing an information recording medium. Of the two adjacent zones of the plurality of zones, the zone located on the inner circumference side is Zone A, the zone located on the outer circumference side is Zone B, the focused light intensity of Zone A is Pin, and the focus of Zone B is The light intensity is Pout,
The minimum value that can be taken by the focused light intensity Pin of the zone A is Pinmin, the maximum value is Pinmax, the minimum value that can be taken by the focused light intensity Pout of the zone B is Poutmin, and the maximum value is Poutmax,
In the zone A, the focused light intensity Pin is gradually increased in the range from the Pinmin to the Pinmax as going to the outer peripheral side, and the value of the focused light intensity Pin at the outermost periphery of the zone A is PinzoneAout,
When the focused light intensity Pout gradually increases in the range from the Poutmin to the Poutmax as it goes to the outer peripheral side in the zone B, and the value of the focused light intensity Pout in the innermost periphery of the zone B is PoutzoneBin In addition,
The relationship between the PinoutBin and the PinzoneAout is
PoutzoneBin ＝ PinzoneAout
The method for producing an optical information recording medium according to claim 4, wherein: Of the two adjacent zones of the plurality of zones, the zone located on the inner circumference side is Zone A, the zone located on the outer circumference side is Zone B, the focused light intensity of Zone A is Pin, and the focus of Zone B is The light intensity is Pout,
The minimum value that can be taken by the focused light intensity Pin of the zone A is Pinmin, the maximum value is Pinmax, the minimum value that can be taken by the focused light intensity Pout of the zone B is Poutmin, and the maximum value is Poutmax,
In the zone A, the focused light intensity Pin is gradually increased in the range from the Pinmin to the Pinmax as going to the outer peripheral side, and the value of the focused light intensity Pin at the outermost periphery of the zone A is PinzoneAout,
When the focused light intensity Pout gradually increases in the range from the Poutmin to the Poutmax as it goes to the outer peripheral side in the zone B, and the value of the focused light intensity Pout in the innermost periphery of the zone B is PoutzoneBin In addition,
The relationship between the PinoutBin and the PinzoneAout is
PoutzoneBin> PinzoneAout
5. The method of manufacturing an optical information recording medium according to claim 4, wherein the difference between the PoutzoneBin and the PinzoneAout is minimized. A method of manufacturing an optical information recording medium having a phase change recording layer on a disk-shaped substrate,
Obtaining a recording medium on which the recording layer is formed;
An initial crystallization step of initial crystallization of the recording layer by scanning a light spot formed by irradiating the recording layer with focused light in a circumferential direction of the recording medium,
In the initial crystallization step, the scanning line speed when the light spot is scanned in the circumferential direction is increased toward the outer peripheral portion of the recording medium, and the intensity of the focused light is increased as the scanning line speed increases. In the case of initial crystallization of the entire crystallization region ,
The rotational speed R0 per unit time of the recording medium is constant until it reaches a predetermined radial position from the innermost peripheral position of the initial crystallization region of the recording medium toward the outer peripheral side of the recording medium, From the predetermined radial position to the position of the outermost periphery of the initial crystallization region, the scanning line speed is constant ,
A method of manufacturing an optical information recording medium, wherein a linear velocity at the predetermined radial position is a maximum linear velocity Vmax, and the maximum linear velocity Vmax is set so as to satisfy the following condition.
(I) A plurality of recording media are prepared, and the recording layer formed on an arbitrary track in the initial crystallization region is initially crystallized at an arbitrary linear velocity with respect to one of the recording media. .
(Ii) Recording is performed twice on the track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) Repeat (i) to (iv) by changing the recording medium and changing the linear velocity.
(Vi) The linear velocity that makes J2 / J10 obtained from the jitter values J2 and J10 obtained at the respective linear velocities 1.6 or less is the maximum linear velocity Vmax. The method for manufacturing an optical information recording medium according to any one of claims 1 to 8, wherein the focused beam is a laser beam. In the initial crystallization step, in the optical information recording medium in which the maximum linear velocity LVmax capable of erasing an amorphous recording mark formed on the optical information recording medium is approximately 20 m / s, the recording is performed. the maximum linear velocity to be used for initial crystallization of the layer, the manufacturing method of the optical information recording medium according to any one of claims 1 to 9, characterized in that the said LVmax more. An initialization device for initial crystallization of the recording layer of a recording medium having a phase change recording layer on a disk-shaped substrate,
A controller that scans a light spot formed by irradiating focused light on the recording layer in a circumferential direction of the recording medium;
The control unit increases the linear velocity at the time of scanning the light spot in the circumferential direction toward the outer periphery of the recording medium, and increases the intensity of the focused light as the scanning linear velocity increases, so that the entire surface of the initial crystallization region Is configured to initially crystallize ,
Wherein the control unit, the rotation speed R0 per unit of the recording medium time adapted to a constant, configured to rotate the recording medium based on the rotation speed R0 which is set so as to satisfy the following conditions An initialization device characterized in that:
(I) A plurality of recording media are prepared, and one of the recording media is rotated at an arbitrary number of revolutions, and at least the recording layer formed on the innermost track of the recording area of the recording medium is initially crystallized. Turn into.
(Ii) Recording is performed twice on the innermost track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) After initial crystallization is performed on another recording medium at a rotational speed different from the rotational speed of (i), the above (ii) to (iv) are performed.
(Vi) The operation of (v) is repeated while changing the recording medium.
(Vii) The relationship between J2 / J10 obtained from the jitter values J2 and J10 obtained from the recording medium initially crystallized at each rotational speed and the rotational speed at the time of initial crystallization is obtained. And R0 is set to the rotation speed which makes J2 / J10 1.6 or less. An initialization apparatus for initial crystallization of a recording layer of a recording medium having a phase change recording layer on a disk-shaped substrate,
A controller that scans a light spot formed by irradiating focused light on the recording layer in a circumferential direction of the recording medium;
The control section is configured entirely of initial crystallized region to initial crystallization by increasing the linear velocity at the time of scanning the light spot in the circumferential direction as the outer peripheral portion of the recording medium,
The initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, and the control unit makes the intensity of the focused light irradiated in each zone constant, and the zone on the outer peripheral side of the recording medium An initialization device configured to increase the intensity of focused light.   13. The initialization apparatus according to claim 12, wherein the control unit is configured to make a rotation speed R0 per unit time of the recording medium constant. An initialization apparatus for initial crystallization of a recording layer of a recording medium having a phase change recording layer on a disk-shaped substrate,
A controller that scans a light spot formed by irradiating focused light on the recording layer in a circumferential direction of the recording medium;
The control unit increases the linear velocity at the time of scanning the light spot in the circumferential direction as the outer peripheral portion of the recording medium, and increases the intensity of the focused light as the scanning linear velocity increases, so that the entire surface of the initial crystallization region Is configured to initially crystallize ,
The initial crystallization region is divided into a plurality of zones along the radial direction of the recording medium, and the control unit keeps the rotational speed at the innermost circumferential position in each zone constant, and the innermost circumferential in each zone. An initialization apparatus characterized in that the scanning linear velocity is constant from the outermost circumference to the outermost circumference. 15. The control unit according to claim 14 , wherein the control unit is configured to make the intensity of the focused light irradiated in each zone constant, and to increase the intensity of the focused light in a zone on the outer peripheral side of the recording medium. Initialization device. Of the two adjacent zones of the plurality of zones, the zone located on the inner circumference side is Zone A, the zone located on the outer circumference side is Zone B, the focused light intensity of Zone A is Pin, and the focus of Zone B is The light intensity is Pout,
The minimum value that can be taken by the focused light intensity Pin of the zone A is Pinmin, the maximum value is Pinmax, the minimum value that can be taken by the focused light intensity Pout of the zone B is Poutmin, and the maximum value is Poutmax,
In the zone A, the focused light intensity Pin is gradually increased in the range from the Pinmin to the Pinmax as going to the outer peripheral side, and the value of the focused light intensity Pin at the outermost periphery of the zone A is PinzoneAout,
When the focused light intensity Pout gradually increases in the range from the Poutmin to the Poutmax as it goes to the outer peripheral side in the zone B, and the value of the focused light intensity Pout in the innermost periphery of the zone B is PoutzoneBin In addition,
The relationship between the PinoutBin and the PinzoneAout is
PoutzoneBin ＝ PinzoneAout
15. The initialization apparatus according to claim 14 , wherein the control unit is configured to control the intensity of the focused light based on the intensity of the focused light set to be. Of the two adjacent zones of the plurality of zones, the zone located on the inner circumference side is Zone A, the zone located on the outer circumference side is Zone B, the focused light intensity of Zone A is Pin, and the focus of Zone B is The light intensity is Pout,
The minimum value that can be taken by the focused light intensity Pin of the zone A is Pinmin, the maximum value is Pinmax, the minimum value that can be taken by the focused light intensity Pout of the zone B is Poutmin, and the maximum value is Poutmax,
In the zone A, the focused light intensity Pin is gradually increased in the range from the Pinmin to the Pinmax as going to the outer peripheral side, and the value of the focused light intensity Pin at the outermost periphery of the zone A is PinzoneAout,
When the focused light intensity Pout gradually increases in the range from the Poutmin to the Poutmax as it goes to the outer peripheral side in the zone B, and the value of the focused light intensity Pout in the innermost periphery of the zone B is PoutzoneBin In addition,
The relationship between the PinoutBin and the PinzoneAout is
PoutzoneBin> PinzoneAout
The control unit is configured to control the intensity of the focused light based on the intensity of the focused light set so that the difference between the PoutzoneBin and the PinzoneAout is minimized. The initialization apparatus according to claim 14 . An initialization apparatus for initial crystallization of a recording layer of a recording medium having a phase change recording layer on a disk-shaped substrate,
A controller that scans a light spot formed by irradiating focused light on the recording layer in a circumferential direction of the recording medium;
The control unit increases the linear velocity at the time of scanning the light spot in the circumferential direction as the outer peripheral portion of the recording medium, and increases the intensity of the focused light as the scanning linear velocity increases, so that the entire surface of the initial crystallization region Is configured to initially crystallize ,
The control unit is
The rotational speed R0 per unit time of the recording medium is constant until it reaches a predetermined radial position from the innermost peripheral position of the initial crystallization region of the recording medium toward the outer peripheral side of the recording medium, From the predetermined radial position to the position of the outermost periphery of the initial crystallization region, the scanning line speed is constant ,
An initialization apparatus, wherein the maximum linear velocity Vmax at the predetermined radial position is set so as to satisfy the following condition.
(I) A plurality of recording media are prepared, and the recording layer formed on an arbitrary track in the initial crystallization region is initially crystallized at an arbitrary linear velocity with respect to one of the recording media. .
(Ii) Recording is performed twice on the track.
(Iii) The jitter value J2 of the recording mark formed after the second recording is measured.
(Iv) Recording is further performed eight times, and the jitter value J10 of the recording mark formed after the eighth recording is measured.
(V) Repeat (i) to (iv) by changing the recording medium and changing the linear velocity.
(Vi) The linear velocity that makes J2 / J10 obtained from the jitter values J2 and J10 obtained at the respective linear velocities 1.6 or less is the maximum linear velocity Vmax. The initialization apparatus according to claim 11 , wherein the focused light is laser light.

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