JP3885490B2 - Information recording disk - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information recording disk such as an optical disc having recording areas of two types of recording densities.
[0002]
[Prior art]
Generally, an information recording disk such as a CD (Compact Disc) or a DVD (Digital Versatile Disc) is known as a storage medium capable of recording and reproducing a large amount of information, and is used for recording various data, audio signals, video signals, and the like. ing. With regard to this type of storage medium, a high-density disk using a purple laser capable of recording and reproducing at a higher density is now being developed. In this typical example, a violet laser having a wavelength of about 405 nm is used, the recording / reproducing lens is raised to about NA 0.85, the thickness of the optical protective layer is about 0.1 mm, and the recording density of the CD is 25. An optical disk having a recording density of ˜40 times, and this optical disk has a higher recording density (storage capacity) than DVD.
[0003]
By the way, with respect to devices that record and reproduce optical discs of various standards with different recording densities as described above, the old standard devices operate based on the old standards, and the new standard devices comply with the new standards. Based on this point, an optical disc having recording areas with different recording densities on one optical disc has been proposed. A technique for recording / reproducing information of different recording densities on a single optical disk of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-1649999, in which the inner peripheral side is an area having the same recording density as the CD and the outer peripheral side is several times the CD. An optical disc having a high recording density is disclosed. A technique in which an area having the same recording density as a CD and an area having the same recording density as a DVD are coexisted on one optical disk is disclosed in Japanese Patent Application Laid-Open No. 8-830906 by the present applicant.
[0004]
[Problems to be solved by the invention]
By the way, the above-described high recording density optical disc (hereinafter also referred to as a high density disc), which is positioned above the DVD in terms of recording density and storage capacity, performs recording and reproduction of a larger capacity than DVD. Compatibility with CDs and DVDs that are widely used is a problem. In order to solve this problem, optical pickups compatible with conventional CDs and DVDs have been prepared separately for high-density disk recording / reproducing apparatuses and reproducing apparatuses.
However, since an optical pickup for recording / reproducing an optical density disk is not prepared in a device that performs recording / reproducing of a disk positioned below a high-density disk such as a CD or DVD, backward compatibility can be achieved. However, upward compatibility was difficult to achieve.
Also, the structure of the three types of discs, CD, DVD, and optical density disc, are different. However, if recording / reproduction on a high-density disc can be performed by a lower-level recording / reproducing machine such as a CD, it is very much for the user. It will be convenient.
The present invention has been made in view of the above points, and an object thereof is to provide an information recording disk having recording areas of two types of recording densities.
[0005]
[Means for Solving the Problems]
Defined in claim 1 the invention is on the same plane of one side of a substrate having optical transparency, the first region and formed by forming irregularities of pits with different densities by dividing the radius Direction from the center hole A signal recording surface having a second region ; and a light-transmitting protective film formed on one surface side of the substrate so as to cover the first region and the second region. Forming a first label printing portion in a region corresponding to the first region on any one of the surfaces of the protective protective film, and forming a second label printing portion in a region corresponding to the second region on the other side. It is an information recording disk characterized by comprising .
In this case, for example, as defined in claim 2, the light transmittance of the label printing portion formed on the center hole side among the first and second label printing portions is set to 50% or more.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an information recording disk according to the present invention will be described in detail with reference to the accompanying drawings.
1 is a schematic sectional view showing an example of an information recording disk according to the present invention, FIG. 2 is a partially enlarged view showing first and second areas of the disk in FIG. 1, and FIG. 3 is a plan view showing the information recording disk. 4 is a plan view showing an example of a character drawn using an array of points, and FIG. 5 is a partially enlarged view showing the points in FIG.
In general, the optical protective layer of a CD has a thickness of 1.2 mm, the optical protective layer of a DVD has a thickness of 0.6 mm, and the thickness of each optical disk is about 1.2 mm. Storing the recording signals corresponding to both of these disks in one disk requires a transmission / reflection film having wavelength selectivity and requires a complicated process for manufacturing the disk. In the embodiment of the present invention, it is possible to store a recording area having the same recording density as a CD and a recording area having a recording density of 25 to 40 times on a single disk plane, so that one optical disk can be used for a CD. The recording / reproducing apparatus and the recording / reproducing apparatus corresponding to the high density disc can be used for recording / reproducing.
[0007]
As shown in the figure, an optical disc D1 as an information recording disk has a center hole 2 in the center, and is divided into two concentric circles in order from the center hole 2 outward in the radial direction. The second region 6 is formed, and the first region 4 and the second region 6 are signal recording surfaces having different recording densities.
Specifically, the first area 4 on the inner circumference side is a recording area having the same recording density as that of a CD, and the second area 6 on the outer circumference side is a recording area having the same recording density as that of the above-described high-density disk (see FIG. (See also 3). For recording / reproduction of the second region 6, as described above, a violet laser having a wavelength of about 405 nm is used, and an optical pickup in which the NA of the recording / reproduction lens is increased to about 0.85 is used.
[0008]
As shown in FIG. 2, the first area 4 and the second area 6 have different formation densities (recording densities) on the same plane on one side of the optically transparent substrate 8 made of, for example, polycarbonate of the optical disk D1. Concavities and convexities 10A and 10B such as pits are formed. Here, for example, the concavities and convexities 10A in the first area 4 correspond to the recording density of the CD, and the concavities and convexities 10B in the second area 6 correspond to the recording density of the above-described high-density disc. It corresponds to. A light reflecting film 12 made of, for example, aluminum or the like is formed on the surface on which both the unevennesses 10A and 10B are formed, and a transparent film 16 made of, for example, polycarbonate or the like is further bonded thereto via an adhesive layer 14. Are stacked. The thickness of the transparent film 16 is about 0.1 mm. A first region lead-in portion 18 is formed on the inner peripheral side in the first region 4, and a second region lead-in portion 20 is formed on the inner peripheral side in the second region 6.
[0009]
Then, a label printing portion 22 for the first area is formed on the upper surface side in FIG. 1 corresponding to the first area 4, and on the opposite side to the above in FIG. 1 corresponding to the second area 6. A label printing section 24 for the second region is formed on the lower surface side. In this case, the light transmittance of the label printing unit 22 for the first area is set to 50% or more, and as will be described later, this area can be passed with the focus servo of the optical pickup locked.
As a result of such a configuration, in FIG. 1, the incident optical path surface is downward with respect to the first region 4 and laser light is incident from below, and the second region 6 is upward and laser light is incident from above. Therefore, at the time of actual recording / reproduction, the optical disc D1 is used with its front and back reversed in correspondence with the surface to be recorded / reproduced.
[0010]
Further, the optical disk D1 has a radius of about 23 mm on the inner peripheral side of the first area 4 on the side where the label printing section 22 for the first area is formed (upper surface in FIG. 1). Information indicating that the second area 6 having a high recording density exists on the outer peripheral side of D1 is provided as, for example, barcode information 26.
FIG. 3 shows bar code information 26 that can be read by rotating the disk around a disk radius of 23 mm. In the illustrated example, the barcode information 26 is not formed over the entire circumference of the disk, but is formed, for example, about 5/6 of the entire circumference.
Such a technique is known on DVD as Burst Cutting Aria. In the example of DVD, information of up to 188 bytes can be recorded and reproduced. Therefore, if the optical disk D1 has the second area 6 and the start radius of the second area 6 is recorded here, the recording / reproducing apparatus can This is read at the beginning of reproduction, and the optical pickup is fast-forwarded to the start radius of the second area 6 where the information in the lead-in portion 20 of the second area 6 is read, and thereafter normal recording / reproduction operation is performed. Like.
[0011]
In order to perform the operation as described above, the optical pickup which has read the barcode information 26 with a disk radius of about 23 mm needs to reach the second area 6 beyond the label printing section 22 for the first area. Here, once the focus servo is turned off, the focus servo needs to be re-locked at the disk inner periphery where the second area 6 starts, or at the outer periphery with a disk radius of about 50 mm. With regard to such re-locking of the focus servo, since the disc surface shake generally increases as it goes to the outer periphery, the risk of re-locking is great. Therefore, for the label printing unit 22 in the first area 4, a printing method for the label printing unit 22 for the first area is performed so that the optical pickup can move in the radial direction while rotating the disk and locking the focus servo. It prescribes.
[0012]
There are two printing methods. In the first example, the printing method is a normal method. As described above, the property of the printing ink is set to a transmittance of 50% or more with respect to the reading light of the second region 6. . According to this, the reciprocal transmittance becomes 25% or more, and the optical pickup proceeds to the second area 6 while proceeding with the label printing section 22 for the first area while keeping the focus servo locked, for this decrease in light quantity. I can do it. In the second example, without performing the solid printing as described above, the printing is performed with a set of a large number of points, and the size of the points is smaller than the size of the light spot on the surface that the reading light creates, What is necessary is just to make the average value of the light transmittance over the said point 50% or more. As a result, a transmissivity of 25% or more can be obtained by going back and forth, and the optical pickup advances the label printing section 22 for the first area while keeping the focus servo locked against this amount of light reduction. The second region 6 can be reached.
[0013]
FIG. 4 is a specific example in which characters are drawn using the array of points 30, and the characters [JVC] are shown. This ensures both the visibility of the characters and the condition that the focus servo can easily be locked.
FIG. 5 is an enlarged view of a part of the characters in FIG. 4. The reading spot of this embodiment has a diameter of about 0.13 mm on the label printing surface 0.1 mm away from the focal point. When a circle is used as the dot 30, if the diameter r 1 is 0.16 mm or less and the distance R 1 between the points is 0.26 mm in each of the two-dimensional directions, the light transmittance is 70% or more one-way. 50% or more. Here, the point of label printing is assumed to have a light transmittance of 0, the area is 0.02 mm ² , the unit area including this point including the transparent portion is 0.0676 mm ² , and a transmittance of 70% is obtained. become.
[0014]
Here, the recording / reproducing apparatus (including the reproducing apparatus) of the optical disc D1 will be briefly described with reference to FIG.
In FIG. 6, 32 is a spindle motor that rotates the optical disk D1, and 34 is an optical pickup that moves in the radial direction of the disk. This optical pickup 34 has, for example, an optical system for CD reproduction and an optical system for high-density disk reproduction, and is selectively used. The overall operation of the recording / reproducing apparatus is controlled by the control circuit 36, and the signal obtained by the optical pickup 34 is sent to the recording / demodulation circuit 38 and is interpreted by the control circuit 36 to discriminate the disc and the A / B surface. Make a decision. For convenience, in FIG. 1, the upper surface is the A surface and the lower surface is the B surface.
Based on the determination, the disc information is reproduced and the signal is output to the input / output circuit 40.
[0015]
Next, the case of reproducing such an optical disc D1 will be described.
In FIG. 1, the optical pickup is located below the optical disk D1, and this state may be used when recording and reproducing the first area 4, and the optical disk D1 needs to be turned over when recording and reproducing the second area 6. There is.
First, according to the standard, the optical pickup 34 has lead-in information that is usually located near a disc radius of 23 mm, here, the first area lead-in portion 18 (in the case of the first area reproduction) and the barcode information 26 (second area). Go to read area playback). When reproducing the first area 4 on the inner circumference side, the optical pickup 34 accesses the first area 4 as it is.
[0016]
On the other hand, when reproducing the second area 6 on the outer peripheral side, the control circuit 36 recognizes that the target area exists on the outer peripheral side, and connects the optical pickup 34 to the first inner peripheral side. The second area 6 is accessed by reading the information in the lead-in portion 20 for the second area through the first area 4 and moving to the second area 6 on the outer periphery.
Here, when the optical pickup 34 passes through the first region 4, laser light is irradiated to the label printing unit 22 for the first region. As described above, the light transmission of the label printing unit 22 is performed. Since the rate is set to 50% or more, the optical pickup 34 can pass across the first area 4 with its focus servo turned on, and appropriately access the lead-in portion 20 for the second area. Is possible.
[0017]
When the above operations are summarized with reference to the flow shown in FIG. 7, first, the loaded disk is discriminated (S1), and as a result, in this embodiment, it is recognized as a single CD or a single high-density disk. If so, recording / reproduction is performed as it is according to the normal sequence (S2).
If the disc is recognized as a disc according to the present invention as a result of the discrimination, it is next discriminated whether the recording / reproducing surface is the A surface or the B surface (S3). Here, when it is recognized that the B surface which is the first area 4 is reproduced, recording and reproduction are performed on the first area 4 according to the normal sequence in the same manner as described above (S2).
On the other hand, when it is recognized that the second area 6 which is the high-density area on the A surface is reproduced, the second area 6 is moved across the label printing section 22 for the first area while the focus servo of the optical pickup is turned on. It moves to the area lead-in part 20 (S4). Thereafter, recording / reproduction is performed on the second area 6 in accordance with a normal sequence (S2).
[0018]
In the above embodiment, the optical disc has two types of recording areas, that is, the first area 4 and the second area 6, and the information indicating that the second area 6 is located on the outer peripheral side is a bar. However, the present invention is not limited to this, and the information may be inserted together in the first area lead-in portion 18, and the recording of the same specifications as in the second area 6 may be performed. An area may be provided in the first area lead-in portion. In this case, as shown in FIG. 8, the first area label printing unit 22 is not provided in the part corresponding to the first area lead-in unit 18, and the part 42 is left blank.
Here, the description has been made so as to combine the specification of the CD with the specification of the recording density of 25 to 40 times, but it is needless to say that the combination is not limited to this.
[0019]
【The invention's effect】
As described above, according to the optical information recording medium of the present invention, the following excellent operational effects can be exhibited.
Two types of optical discs, such as a CD and an optical disc with a recording density of 25 to 40 times the same, are stored in one disc and the recording / reproducing surface is arranged on the same plane, so that the productivity of the disc is good. This disc can serve two types of applications, such as CDs and high density discs. In addition, this information recording disk can be used for a widely used CD device, for example, even if the device corresponding to the high-density disk is not widely used.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an example of an information recording disk according to the present invention.
FIG. 2 is a partially enlarged view showing a first region and a second region of the disk in FIG.
FIG. 3 is a plan view showing an information recording disk.
FIG. 4 is a plan view showing an example of a character drawn using an array of points.
FIG. 5 is a partially enlarged view showing the points in FIG. 4;
FIG. 6 is a block diagram showing an optical disc recording / reproducing device.
FIG. 7 is a diagram showing an operation flow at the time of lead-in.
FIG. 8 is a cross-sectional view showing another example of the information recording medium of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Center hole, 4 ... 1st area | region, 6 ... 2nd area | region, 8 ... Board | substrate, 10A, 10B ... Unevenness, 12 ... Light reflection film, 14 ... Adhesive layer, 16 ... Transparent film, 18 ... Lead for 1st area | region IN section, 20 ... second area lead-in section, 22 ... first area label printing section, 24 ... second area label printing section, 26 ... bar code information, D1 ... optical disc (information recording medium).

Claims (2)

On the same plane of one side of a substrate having optical transparency, and a signal recording surface having a first region and a second region by forming a concavo-convex pits such as at different densities by dividing the radius Direction from the center hole ,
A light-transmitting protective film formed on one side of the substrate so as to cover the first region and the second region,
A first label printing portion is formed in a region corresponding to the first region on one of the other surface side of the substrate and the surface of the light-transmissive protective film, and corresponds to the second region on the other side. An information recording disk comprising a second label printing section formed in an area . 2. The information recording disk according to claim 1 , wherein a light transmittance of a label printing portion formed on the center hole side among the first and second label printing portions is 50% or more. .

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