JP3343326B2 - Master information carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the large-capacity, about the master information responsible body used for pre-recording predetermined information signals on a magnetic recording medium used in a magnetic recording and reproducing apparatus having a high recording density.

[0002]

2. Description of the Related Art In order to realize a small and large-capacity magnetic recording / reproducing apparatus, it is increasingly required to increase the recording density. In a hard disk drive, which is a typical magnetic recording / reproducing apparatus, the areal recording density is 1 Gbit / in ^2.
(1.55 Mbit / mm ² ) has already been commercialized, and several years later, the areal recording density is 10 Gbit / mm ^2.
As the practical application of an in ² (15.5 Mbit / mm ² ) device is expected, rapid technical progress is recognized.

[0003] As a technical background enabling such a high recording density, there has been an emergence of a new signal processing method such as an improvement in medium performance, a head-disk interface performance, and a partial response. The improvement has greatly contributed to higher recording density. However, in recent years, the trend of increase in track density has greatly exceeded the trend of increase in linear recording density. This is due to the practical use of a magnetoresistive element type head, which has much better reproduction output performance than a conventional induction type magnetic head. At present, a few μm
A signal recorded with a track width of can be reproduced with a good SN ratio. With a further improvement in head performance, it is expected that the track pitch will reach the submicron range in the near future.

In order for the head to accurately scan such a narrow track and reproduce a signal with a good SN ratio, the tracking servo technique of the head plays an important role. Detailed information on such tracking servo technology is disclosed in, for example, Journal of the Japan Society of Applied Magnetics, Vol. 20, No. 3, p. 771 (1996), Yamaguchi, "High-precision Servo Technology for Magnetic Disk Drives". Have been. According to this document, in the current hard disk drive, one round of the disk, that is, 36
At an angle of 0 degree, an area is provided in which a tracking servo signal, an address information signal, a reproduction clock signal, and the like are recorded at a constant angle interval. Recording such an information signal in advance is called preformat recording. By reproducing these signals at regular intervals, the magnetic head can check the position of the head, and can accurately scan the track while making corrections as necessary.

Since the above-mentioned tracking servo signal, address information signal, reproduction clock signal, and the like are reference signals for the head to accurately scan the track, it is required to have high head positioning accuracy in recording. . For example, the 93rd meeting of the Japan Society of Applied Magnetics, 93
-5, p. 35 (1996), Uematsu et al., "Mechanical Servo, HDI Technology Current Status and Prospects," According to the current hard disk drive, after the disk is built into the drive, Preformat recording is performed while strictly controlling the position of the magnetic head using a servo recording device.

[0006] Such preformat recording of servo signals, address information signals, reproduced clock signals, and the like is also performed by a specially designed medium for a removable hard disk to which a large-capacity flexible disk or disk cartridge which has recently been commercialized can be detached. This is performed using a servo recording device.

[0007] Preformat recording by a magnetic head using such a dedicated servo recording device has the following problems. First, since recording by a magnetic head is basically linear recording by relative movement between the head and the medium, the above method of performing recording while strictly controlling the position of the magnetic head using a dedicated servo recording device is not used. In addition, a lot of time is required for preformat recording. Furthermore, dedicated servo recording devices are quite expensive. Therefore, the cost required for preformat recording increases.

This problem becomes more serious as the track density of the magnetic recording device increases. In addition to the increase in the number of tracks in the disk radial direction, the time required for preformat recording is prolonged for the following reasons. That is, the higher the track density, the higher the accuracy of the head positioning is required. Therefore, it is necessary to reduce the angular interval for providing a servo area for recording information signals such as a servo signal for tracking in one round of the disk. Therefore, the higher the recording density of the device, the larger the amount of signals to be preformat-recorded on the disc, and the more time is required.

Although the magnetic disk medium tends to be smaller in diameter, there is still a great demand for a 3.5-inch or 5-inch large-diameter disk. The larger the recording area of the disc, the larger the signal amount to be preformat-recorded. The time required for preformat recording also greatly affects the cost performance of such a large-diameter disk.

The second in conventional preformat recording
The problem is that the magnetic field spreads due to the spacing between the head and the medium and the shape of the pole at the tip of the recording head, so that the magnetization transition at the end of the preformat-recorded track lacks sharpness. .

Since the recording by the magnetic head is basically a dynamic linear recording by the relative movement between the head and the medium, a certain amount of head-medium spacing is provided from the viewpoint of the interface performance between the head and the medium. I have no choice. Further, the current magnetic head usually has a structure having two elements that separately perform recording and reproduction, so that the leading edge side pole width of the recording gap is equivalent to the recording track width, and the trailing edge side pole width is several times the recording track width. It is larger than above.

Both of the above two points cause a spread of the recording magnetic field at the end of the recording track, and as a result, the magnetization transition at the end of the track on which the preformat recording is performed lacks sharpness, or both sides of the track end. This results in the generation of an erased area in In the current tracking servo technology, the position of the head is detected based on the amount of change in the reproduction output when the head scans off the track. Therefore, not only is the S / N ratio excellent when the head scans the track accurately as in reproducing the data signal recorded between the servo areas, but also the reproduction output when the head scans off the track. It is required that the amount of change, that is, the off-track characteristic is steep. Accordingly, if the magnetization transition at the end of the track on which the preformat recording is performed lacks sharpness as described above, it is difficult to realize an accurate tracking servo technique in future submicron track recording.

Various techniques have already been proposed for solving the two problems in the preformat recording by the magnetic head as described above. For example, JP
Japanese Patent Application Laid-Open No. 3-183623 discloses a copying technique such as a tracking servo signal using a magnetic transfer technique as a solution to the first problem. It is a fact that the productivity at the time of preformat recording is improved by using this magnetic transfer technique. However, this magnetic transfer technology is effective for magnetic disk media having a relatively low coercive force and a low areal recording density, such as a flexible disk, but has a surface area on the order of several hundred megabits to a gigabit, such as today's hard disk media. It cannot be used for a high coercive force medium having a resolution that bears the recording density.

In the magnetic transfer technique, it is necessary to apply an AC bias magnetic field having an amplitude of about 1.5 times the coercive force of the transferred disk in order to secure transfer efficiency. Since the master information recorded on the master disk is a magnetization pattern, in order to prevent the master information from being demagnetized by the AC bias magnetic field, the coercive force of the master disk should be at least about three times the coercive force of the transferred disk. It is required that there be. The coercive force of the current high-density hard disk medium is 1500 to 2500 to support a high areal recording density.
There is also Oersted. In order to support a surface recording density of 10 gigabit order in the future, this value should be 3000 to
It is expected to reach 4000 Oersteds. In other words, the master disk currently has 4500-7
500 Oersted, 9000 to 12000 in the future
Oersted coercivity will be required.

It is difficult to realize such a coercive force in the master disk from the viewpoint of selecting a magnetic material. Furthermore, with the current magnetic recording technology, master information cannot be recorded on a master disk having such a high coercive force. Therefore, in magnetic transfer technology,
Considering the coercive force value that can be realized in the master disk, the coercive force of the disk to be transferred is necessarily limited.

[0016] For example, in Japanese Patent Application Laid-Open No. Hei 7-153060, a disk medium substrate having irregularities corresponding to a tracking servo signal, an address information signal, a reproduction clock signal and the like is formed by a stamper, and the substrate is formed on the substrate. A pre-embossed disk technology for forming a magnetic layer has been disclosed. This technique is an effective solution to both of the above two problems. However, it is expected that the uneven shape of the disk surface will affect the flying characteristics of the head during recording / reproduction (or the contact state with the medium in the case of contact recording), and as a result, a problem will occur in the head-medium interface performance. Is done. Also, since the substrate manufactured by the stamper is basically a plastic substrate,
There is also a problem that the substrate cannot be heated at the time of forming the magnetic layer necessary for securing the medium performance, and the required medium S / N ratio cannot be secured.

As described above, the technique described in Japanese Patent Application Laid-Open No. 63-183623 or Japanese Patent Application Laid-Open No. 153060/1993 solves the above-mentioned problems related to preformat recording. Sacrifice important performance and is not a truly effective solution.

Another preformat recording technique is disclosed in Japanese Patent Application No. Hei.
-191889. In this recording technique, an uneven shape corresponding to an information signal is formed on a surface of a base, and a surface of a master information carrier in which at least a surface of a convex portion of the uneven shape is formed of a ferromagnetic material is formed on a surface of a magnetic recording medium. , A magnetization pattern corresponding to the uneven shape of the master information carrier surface is recorded on the magnetic recording medium.

As the ferromagnetic material forming the convex surface of the master information carrier, a soft magnetic film having a high saturation magnetic flux density or a hard or semi-hard magnetic film having a coercivity of 40 kA / m or less is preferably used. . More preferably, when the surface of the master information carrier is brought into contact with the surface of the magnetic recording medium, a DC magnetic field for exciting the ferromagnetic material forming the convex surface of the master information carrier, or for assisting the recording of a magnetization pattern. An AC bias magnetic field is applied. As a result, the problems described above with respect to the technology described in JP-A-63-183623 or JP-A-7-153060 can also be solved.

The recording technique described in the specification of Japanese Patent Application No. 8-191889 is a problem in preformat recording by a magnetic head using a conventional dedicated servo recording apparatus, or Japanese Patent Application Laid-Open No. 63-183623. With respect to the problems of the technology disclosed in Japanese Patent Application Laid-Open No. 7-153060, the following features are provided.

In the recording technique described in the specification of Japanese Patent Application No. 8-191889, unevenness of a master information carrier is generated by a recording magnetic field generated by a ferromagnetic material on a surface of a master information carrier magnetized in one direction. A magnetization pattern corresponding to the shape is recorded on the magnetic recording medium. That is, by forming irregularities corresponding to the tracking servo signal, the address information signal, the reproduction clock signal, and the like on the surface of the master information carrier, preformat recording of these information signals can be performed on the magnetic recording medium.

In this recording technique, recording is performed by a leakage magnetic field generated from a ferromagnetic material in a convex portion due to a change in magnetoresistance due to an uneven shape. Therefore, the recording mechanism is basically the same as that of recording using a conventional magnetic head that performs recording using a leakage magnetic field generated from a recording gap of the magnetic head. However, while the recording by the conventional magnetic head is dynamic line recording by the relative movement of the head and the medium, the recording by the above configuration is a static surface recording without the relative movement of the master information carrier and the medium. It can be said that. Due to such features, Japanese Patent Application No. 8-1918
The recording technique described in the specification of No. 89 provides an effective solution to the above-mentioned problem relating to preformat recording as follows.

First, since this recording technique is surface recording, the time required for preformat recording is much shorter than the recording by a conventional magnetic head. Further, an expensive servo recording device for performing recording while strictly controlling the position of the magnetic head is not required. Therefore, the productivity for preformat recording can be greatly improved, and the production cost can be reduced.

Second, since this recording technique is a static recording that does not involve the relative movement of the master information carrier and the medium, the recording information is brought into close contact with the surface of the magnetic recording medium by the close contact between the master information carrier and the magnetic recording medium. The spacing between them can be minimized. Furthermore, unlike the recording by the magnetic head, the recording magnetic field does not spread due to the pole shape of the recording head. Therefore, the transition of the magnetization at the end of the track on which the preformat recording is performed has an excellent steepness as compared with the recording by the conventional magnetic head. As a result, more accurate tracking becomes possible.

The recording technique described in the specification of Japanese Patent Application No. 8-191889 is a magnetic transfer technique disclosed in Japanese Patent Application Laid-Open No. 63-183623 and Japanese Patent Application Laid-Open No. 7-15306.
There is no problem as described with respect to the pre-embossed disc technology disclosed in Japanese Patent Publication No. That is, there is no restriction on the configuration and magnetic characteristics of the magnetic recording medium on which preformat recording is performed.

For example, in the magnetic transfer technique disclosed in Japanese Patent Application Laid-Open No. 63-183623, a master disk provided with master information recorded by a magnetization pattern is a magnetic recording medium itself, and therefore has a corresponding magnetic recording medium. Requires medium resolution. For this reason, the magnetic flux density and the film thickness of the master disk magnetic layer cannot be made sufficiently large, and the magnitude of the generated transfer magnetic field becomes very small. Further, since the master information is recorded in a magnetization pattern, demagnetization occurs due to the butt magnetization of the dibit, and the transfer magnetic field gradient in the magnetization transition region is gentle. In order to secure sufficient transfer efficiency even with such a weak transfer magnetic field, in the magnetic transfer technique, it is necessary to apply an AC bias magnetic field having an amplitude of about 1.5 times the coercive force of the transferred disk. As a result, as described above, the coercive force of the disk to be transferred is limited, and the disk can be used only for a flexible disk having a relatively low recording density.

On the other hand, the master information carrier described in the specification of Japanese Patent Application No. 8-191889 has master information in a concave and convex pattern. The point that recording is performed by using a leakage magnetic field generated from the ferromagnetic material of the convex portion is similar to recording by a magnetic head. Since the resolution as a magnetic recording medium is not required unlike the master disk in magnetic transfer technology, the magnetic flux density and volume of the ferromagnetic material forming the convex surface of the master information carrier must be as large as that of a conventional magnetic head. As a result, a large recording magnetic field equivalent to that of the magnetic head can be generated. As a result, it is possible to exhibit sufficient recording capability for all magnetic recording media, including ordinary flexible disks, hard disks, and even high coercive force media for gigabit recording in the future.

In the pre-embossed disk technology disclosed in Japanese Patent Application Laid-Open No. 7-153060, the substrate material and shape of the disk medium on which preformat recording is performed are restricted as described above. With respect to the medium SN ratio performance related to the substrate temperature and the flying characteristics of the head (the contact state with the medium in the case of contact recording), the head-medium interface performance was sacrificed. On the other hand, the recording technique described in the specification of Japanese Patent Application No. 8-191889 is not subject to any restrictions on the substrate material and surface shape of the magnetic recording medium on which preformat recording is performed as described above.

[0029]

As described above, the recording technique described in the specification of Japanese Patent Application No. 8-191889 is as follows.
It provides a technology that can perform static surface recording irrespective of the configuration and magnetic characteristics of the magnetic recording medium to be preformatted, and sacrifices other important performance such as medium S / N ratio and interface performance. This is an excellent technique that can efficiently perform good preformat recording without performing.

However, in order to make this recording technique truly effective, it is necessary to realize uniform adhesion between the master information carrier and the magnetic recording medium. If uniform adhesion is not realized between the two, sufficient recording signal intensity cannot be obtained due to spacing loss, and therefore, a satisfactory SN ratio may not be secured. Furthermore, the magnetization transition at the track end lacks sharpness due to the spread of the recording magnetic field, and there is a possibility that sufficient off-track characteristics cannot be obtained.

Therefore, the present invention relates to a technique for statically recording information on a recording medium using a master information carrier having master information as an uneven pattern, wherein the magnetic recording medium is uniformly brought into close contact with the master information carrier. It is another object of the present invention to provide means for performing highly reliable preformat recording.

[0032]

According to a first aspect of the present invention, there is provided a master information carrier comprising, on a surface of a disk-shaped substrate, a region formed of a ferromagnetic thin film and having an uneven pattern corresponding to an information signal; The region where the uneven pattern is not formed is alternately provided at a predetermined angular interval in the circumferential direction, and a plurality of through holes are formed in at least a part of the region where the uneven pattern is not formed. It is characterized by being provided .

A second structure of the master information carrier according to the present invention is a master information carrier comprising: a region in which a surface of a disk-shaped substrate is formed of a ferromagnetic thin film and has an uneven pattern corresponding to an information signal; Are formed alternately at predetermined angular intervals in the circumferential direction, and the surface height of at least a part of the region where the uneven pattern is not formed is the region where the uneven pattern is formed. wherein the lower equalizer Metropolitan than the surface height of the.

[0034]

[0035]

[0036]

[0037] By using <br/> master information responsible of the present invention as described above, it is possible to uniformly contact a magnetic recording medium to the master information carrier, performs highly reliable preformat recording be able to.

[0038]

As means for aligning the master information carrier with the magnetic recording medium, the master information carrier may be aligned with the inner or outer periphery of the master information carrier in accordance with the inner or outer periphery of the magnetic recording medium. Preferably, a marker is located.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. (Embodiment 1) FIG. 3 is a sectional view showing a first embodiment of an apparatus according to the present invention for recording an information signal formed on a master information carrier on a magnetic recording medium. In the figure, 31
a, 31b are master information carriers, 32 is a hard disk, 33 is an upper flange, 34 is a lower flange, 35a, 3
5b is a permanent magnet, 36a and 36b are exhaust devices, 37a and
37b is a three-way valve, and 30 is an O-ring. Permanent magnet 15
The magnetization directions of a and 15b are from the back of the paper to the front.

On the surfaces of the master information carriers 31a and 31b, for example, as shown in FIG. 1, regions 12 having fine irregularities corresponding to information signals are provided at predetermined angular intervals. FIG. 2 is an enlarged view of a part of the region 12 (region A in FIG. 1). The respective areas of the tracking servo signal, the clock signal, and the address information signal are sequentially arranged in the track length direction.
In FIG. 2, a hatched portion is a convex portion, and the surface of the convex portion is formed of a ferromagnetic material such as Co.

A method for forming a fine uneven shape corresponding to such an information signal on the surface of the master information carrier will be described below. First, a ferromagnetic thin film made of Co or the like is formed on a glass substrate having a fine surface roughness and good flatness by a sputtering method. Next, after exposing and developing the resist film using a lithography technique using a laser beam or an electron beam such as a photolithography method, an uneven shape is formed by dry etching or the like.
Alternatively, after forming and patterning a resist film on the surface of the substrate, a ferromagnetic thin film made of Co or the like is formed, and the resist film is removed to form an uneven shape by a so-called lift-off method.

The method of forming the irregularities is not limited to these, and fine irregularities may be directly processed by using, for example, a laser, an electron beam or an ion beam, or by machining. The method of forming a ferromagnetic thin film on a glass substrate is not limited to a sputtering method, and a conventional general thin film forming method such as a vacuum deposition method, an ion plating method, a CVD method, and a plating method is used. be able to.

The level difference between the surface of the convex portion and the bottom surface of the concave portion corresponding to the information signal depends on the surface property of the magnetic recording medium on which the master information is recorded and the bit size of the master information. Is 0.05 μm or more, preferably 0.1 μm or more. In one embodiment, 0.5 μ
m.

The material of the ferromagnetic thin film forming the surface of the convex portion of the concavo-convex shape is not limited to Co. Many types of magnetic materials can be used regardless of a hard magnetic material, a semi-hard magnetic material, and a soft magnetic material. In order to generate a sufficient recording magnetic field irrespective of the type of the magnetic recording medium on which the master information is recorded, the larger the saturation magnetic flux density of the magnetic material, the better. Especially 200
For a high coercivity magnetic disk exceeding 0 Oe or a flexible disk having a large magnetic layer thickness, sufficient recording may not be performed if the saturation magnetic flux density is 0.8 Tesla or less. A magnetic material having a saturation magnetic flux density of 8 Tesla or more, preferably 1.0 Tesla or more is used.

As shown in FIG. 1, the master information carrier 11
The through-hole 13 is provided in a region other than the region 12 in which the uneven shape corresponding to the information signal is formed. Through hole 13
When the substrate of the master information carrier is glass, it can be formed using a known processing method such as ultrasonic processing, laser processing, or wet etching. It is preferable that the diameter of the through hole is as small as possible and the number of the through holes is as large as possible. In one embodiment, the diameter is 1 mm using ultrasonic machining.
Was formed at a rate of one per 3 mm square.

When recording the information signal formed on the master information carrier on a hard disk as a magnetic recording medium, it is necessary to align the center of the master information pattern with the center of the hard disk and then to bring the master information pattern into close contact. To facilitate this alignment, a marker 14 is formed on the inner periphery of the master information carrier 11, as shown in FIG. The marker 14 is formed simultaneously with the uneven shape corresponding to the information signal. The marker 14 formed on the inner periphery of the master information carrier 11 is formed so as to align the inner periphery of the hard disk. However, the marker 14 is formed on the outer periphery of the master information carrier 11 so as to align the outer periphery of the hard disk. A marker may be formed.

In this embodiment, a procedure for recording an information signal formed on a master information carrier on a hard disk as a magnetic recording medium will be described with reference to FIGS. In the present embodiment, the master information carriers 31a and 31b and the hard disk 32 are brought into close contact with the hard disk 32 entirely using the atmospheric pressure. By exhausting air existing between the master information carriers 31a and 31b and the hard disk 32 through the through holes 39 provided in the master information carriers 31a and 31b, the hard disk 32 is pressed against the master information carriers 31a and 31b, The surface of the convex portion of the concavo-convex pattern formed on the information carriers 31a and 31b is in close contact with the hard disk 32. Thereafter, using the permanent magnets 35a and 35b, the master information carrier 31 is used.
By magnetizing the ferromagnetic thin film on the surface of the convex portion of the concavo-convex pattern formed on the a and 31b, an information signal corresponding to the concavo-convex shape is recorded on the hard disk 32. The procedure is described in detail below.

First, as shown in FIG. 5, the hard disk 32 is moved along the circumferential direction by the arrow 51 using the permanent magnet 52.
In advance in the direction of. Note that an electromagnet may be used instead of the permanent magnet. Next, as shown in FIG. 3, the O-ring 30 is attached to the groove of the lower flange 34, and the master information carrier 31b and the hard disk 32 are overlaid thereon.
At this time, since the marker (14 in FIG. 1) for aligning the center of the master information pattern with the center of the hard disk 32 is provided on the master information carrier 31b as described above, this marker is aligned with the inner periphery of the hard disk 32. . Further, the master information carrier 31a and the upper flange 33 having the O-ring 30 mounted in the groove are overlapped on the hard disk 32. At this time, similarly to the above, the marker provided on the inner periphery of the master information carrier 31a is adjusted to the inner periphery of the hard disk 32.

The exhaust device 3 is operated by operating the upper three-way valve 37a.
6a, the upper flange 33 and the master information carrier 31a
To suck the air between. The lower three-way valve 37b is switched so that the space between the lower flange 34 and the master information carrier 31b is at atmospheric pressure. Master information carrier 31a
The air between the hard disk 32 and the hard disk 32 is exhausted through a through hole 39 provided in the master information carrier 31a, so that the hard disk 32
, So that the two are in close contact with each other. Next, FIG.
As shown in (a), the DC excitation magnetic field 41a is applied by rotating the permanent magnet 35a parallel to the upper flange and around the exhaust duct 38a. With this operation,
The ferromagnetic thin film on the surface of the projection of the uneven pattern formed on the master information carrier 31a is magnetized, and an information signal corresponding to the uneven shape is recorded on the hard disk 32. As described above, the hard disk 32 is preliminarily magnetized in the circumferential direction using a permanent magnet or the like in advance. The initial magnetization direction and the direction of the magnetic field applied by the permanent magnet 35a when recording an information signal are recorded. And may be the same or opposite. In one embodiment, the direction is reversed.

Next, the air between the lower flange 34 and the master information carrier 31b is sucked by the exhaust device 36b by operating the lower three-way valve 37b. Upper three-way valve 37a
Is switched so that the space between the upper flange 33 and the master information carrier 31a is at atmospheric pressure. When the air between the master information carrier 31b and the hard disk 32 is exhausted through the through hole 39 provided in the master information carrier 31b, the hard disk 32 is pressed against the master information carrier 31b, and both are brought into close contact with each other.

As shown in FIG. 4B, the permanent magnet 35b
Is turned parallel to the lower flange 34 and around the exhaust duct 38b to apply the DC exciting magnetic field 41b.
By this operation, the ferromagnetic thin film on the surface of the convex portion of the concavo-convex pattern formed on the master information carrier 31b is magnetized, and an information signal corresponding to the concavo-convex shape is transmitted to the hard disk 32.
Will be recorded. In one embodiment, the initial magnetization direction of the hard disk 32 and the permanent magnet 35b are used when recording the information signal.
And the direction of the applied magnetic field was reversed.

According to the above procedure, preformat recording can be performed on both sides of the hard disk 32 in a short time. Instead of using a permanent magnet to magnetize the ferromagnetic thin film on the convex surface of the concave / convex pattern formed on the master information carrier, an electromagnet may be used. Further, since the ferromagnetic thin film on the surface of the master information carrier is magnetized in a state where the upper flange 33 or the lower flange 34 is interposed between the permanent magnet and the master information carrier, the upper flange 33 and the lower flange 34 are not magnetized. The material is preferably a non-magnetic material such as brass steel.

In this embodiment, when the magnetic recording medium is not a hard disk but a flexible disk, if the through-hole provided in the master information carrier is large, the flexible disk is sucked into the through-hole and deformed, so that the preformat recording can be performed accurately. Missing signals or missing signals to be recorded in place. Therefore, as described above, it is preferable that the size of the through hole is as small as possible and that as many as possible. By doing so, highly reliable preformat recording can be performed not only on a hard disk but also on a flexible disk. Further, in the present embodiment, since the master information carriers are arranged on both sides of the magnetic recording medium, preformat recording can be efficiently performed on both sides of the magnetic recording medium in a short time, which can contribute to improvement in productivity.

(Embodiment 2) FIG. 7 is a sectional view showing a second embodiment of the device according to the present invention for recording an information signal formed on a master information carrier on a magnetic recording medium. In the figure, 71 is a master information carrier, 72 is a hard disk, 73 is an upper flange, 74 is a lower flange, 75 is a permanent magnet, and 70 is an elastic plate. 76 is an exhaust device, 7
7 is a three-way valve, 78 is an exhaust duct, 79 is an upper flange 73
And a bolt for fixing the lower flange 74.

On the surface of the master information carrier 71, for example, as shown in FIG. 6A, regions 62 having fine irregularities corresponding to information signals are provided at predetermined angular intervals. A specific example of the information signal recorded in this area is:
It is shown in FIG. 2 as in the first embodiment. As described in the first embodiment, such a concavo-convex shape is obtained by forming a ferromagnetic thin film made of Co or the like on a glass substrate surface having fine surface roughness and good flatness by a sputtering method,
For example, the resist film is formed by exposing and developing a resist film using a lithography technique using a laser beam or an electron beam such as a photolithography method, and then by dry etching or the like.

As shown in FIG. 6, in the present embodiment, the surface of the region 62 and the outer peripheral portion (white blank portion in FIG. 6A) where the uneven shape corresponding to the information signal of the master information carrier 61 is formed. Compared to the height, other areas 63 (FIG. 6A)
(Hatched portion of FIG. 2) is reduced in surface height. Less than,
This region 63 is called a concave region. FIG.
FIG. 3A shows a cross section taken along a one-dot chain line AA in the circumferential direction in FIG. On the region 62, for example, an uneven shape corresponding to the information signal as shown in FIG. 2 is formed. After forming the concavo-convex shape as described above, the concave region 63 is formed using a known processing method such as mechanical processing, ultrasonic processing, or laser processing. The step between the region 62 having the uneven shape and the concave region 63 depends on the thickness of the substrate of the master information carrier 61, but is several tens μm or more, preferably 100 μm.
Above.

When the information signal formed on the master information carrier 61 is recorded on a hard disk as a magnetic recording medium, it is necessary to bring the center of the master information pattern into close contact with the center of the hard disk. Similar to the first embodiment, a marker 64 as shown in FIG. 6 is also formed on the inner periphery of the master information carrier 61 of the present embodiment, whereby the inner periphery of the hard disk is aligned. In this case as well, the marker formation position is not limited to the inner peripheral portion of the master information carrier 61, and the marker may be formed on the outer peripheral portion of the master information carrier 61 so as to align the outer periphery of the hard disk.

In this embodiment, a procedure for recording an information signal formed on a master information carrier on a hard disk as a magnetic recording medium will be described with reference to FIGS. In the present embodiment, the area of the master information carrier 71 where the uneven shape corresponding to the information signal is formed and the hard disk 7
2 and the hard disk 72 are mechanically pressed against each other using the atmospheric pressure. By setting the surface height of the recessed area where the uneven shape corresponding to the information signal is not formed to be lower than the surface height of the area where the uneven shape is formed, the distance between the master information carrier 71 and the hard disk 72 is reduced. A void is formed in By exhausting the air in the gap, the hard disk 72 comes into close contact with the area of the master information carrier 71 where the uneven shape corresponding to the information signal is formed. Then, the permanent magnet 75 magnetizes the ferromagnetic thin film on the convex surface of the concave / convex pattern formed on the master information carrier, thereby recording an information signal corresponding to the concave / convex shape on the hard disk 72. The procedure is described in detail below.

First, as shown in FIG. 5, using a permanent magnet 52, a hard disk 72 is moved along an arrow 51 along a circumferential direction.
In advance in the direction of. Next, as shown in FIG.
2. Overlap the master information carriers 71 in order. Elastic plate 70
A through hole having a size similar to that of the hard disk 72 is formed in the center of. When the master information carrier 71 is overlaid on the hard disk 72, the marker (6 in FIG. 6) is used.
4) is adjusted to the inner circumference of the hard disk 72. Finally, the elastic plate 70 and the upper flange 7 are placed on the master information carrier 71.
Stack three. Various materials having elasticity, such as silicon rubber, can be used for the elastic plate 70. By operating the three-way valve 77, the air is exhausted by the exhaust device 76 between the hard disk 72 and the concave area where the uneven shape corresponding to the information signal of the master information carrier 71 is not formed. As a result, the area where the uneven shape corresponding to the information signal is formed and the hard disk 72 come into close contact with each other. In this embodiment, since the exhaust duct 78 is arranged at the center of the device,
The exhaust conductance at the center of the master information carrier 71 is large. Therefore, the negative pressure due to the exhaust from the central hole of the hard disk 72 largely acts on the central portion of the master information carrier 71, but does not act so strongly on the outer peripheral portion. May have poor adhesion.

Therefore, in the present embodiment, the upper flange 73
And the master information carrier 71, and the lower flange 7
An elastic plate 70 is provided between the hard disk 4 and the hard disk 72, and an upper flange 73 and a lower flange 74 are connected with bolts 79. Then, by adjusting the tightening torque of the bolt 79, the master information carrier 71 and the hard disk 72 are appropriately pressed against each other. In this way, the area of the master information carrier 71 where the uneven shape corresponding to the information signal is formed and the hard disk 72 are in close contact with each other.

Finally, as shown in FIG. 8, a DC exciting magnetic field 81 is applied by rotating the permanent magnet 75 in parallel with the upper flange 73 and along the circumferential direction. By this operation, the ferromagnetic thin film on the surface of the convex portion having the uneven shape corresponding to the information signal formed on the master information carrier 71 is magnetized, and the information signal corresponding to the uneven shape is recorded on the hard disk 72. As described above, the hard disk 72 is initially magnetized in the circumferential direction using a permanent magnet or the like in advance.
The direction of the initial magnetization may be the same as or opposite to the direction of the magnetic field applied by the permanent magnet 75 when recording the information signal. In one embodiment, the direction is reversed. The first
As described in the embodiment, since the ferromagnetic thin film on the surface of the master information carrier is magnetized in a state where the upper flange 73 is interposed between the permanent magnet and the master information carrier, the material of the upper flange 73 is It is preferably a non-magnetic material such as brass steel.

As described above, in the present embodiment, the surface height of the region where the uneven shape corresponding to the information signal of the master information carrier is not formed is lower than the surface height of the region where the uneven shape is formed. This creates a gap between the master information carrier and the hard disk. By exhausting the air in the gap, the area where the uneven shape is formed is brought into close contact with the hard disk. Further, by providing means for mechanically pressing the master information carrier and the hard disk, preformat recording with higher reliability is enabled.

[0064]

As described above, according to the present invention, a through-hole is provided in at least a part of a region where a concave / convex shape corresponding to an information signal of a master information carrier is not formed. By exhausting the air existing between the recording medium or, or the surface height of at least a part of the region where the uneven shape is not formed,
Lower than the surface height of the area where the uneven shape was formed,
By exhausting the gas present between the region where the uneven shape is not formed and the magnetic recording medium, the master information carrier and the magnetic recording medium are brought into close contact with each other to realize highly reliable preformat recording. Can be.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a structure of a master information carrier according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a portion A of FIG. 1, showing an example of a concavo-convex pattern corresponding to an information signal formed on a surface of a master information carrier.

FIG. 3 is a diagram showing a configuration of a master information magnetic recording apparatus for recording the information signal of the master information carrier of FIG. 1 on a magnetic recording medium.

4 is a diagram showing a method for recording an information signal of a master information carrier on a magnetic recording medium using the master information magnetic recording device of FIG. 3;

FIG. 5 is a diagram showing an example of a method for initial magnetizing a magnetic recording medium in advance.

FIG. 6 is a diagram schematically showing a planar structure and a cross-sectional structure of a master information carrier according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a master information magnetic recording apparatus for recording information on the master information carrier of FIG. 6 on a magnetic recording medium.

8 is a diagram showing a method for recording an information signal of a master information carrier on a magnetic recording medium using the master information magnetic recording device of FIG. 7;

[Explanation of symbols]

11, 31a, 31b, 61, 71 Master information carrier 12 62 Region in which unevenness corresponding to information signal is formed 13, 39 Through hole 14, 64 Hard disk inner peripheral position alignment marker 32, 72 Hard disk 33, 73 On Flange 34, 74 Lower flange 35a, 35b, 75 Permanent magnet 36a, 36b, 76 Exhaust device 37a, 37b, 77 Three-way valve 38a, 38b, 78 Exhaust duct 30 O-ring 41a, 41b, 81 DC excitation magnetic field 63 Recessed area 70 Elasticity Board 79 bolt

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiwa Higashima 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Tatsuro Ishida 1006 Kadoma Kadoma Kadoma, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-4-134629 (JP, A) JP-A-48-53704 (JP, A) JP-A-50-60212 (JP, A) JP-A-63-183623 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 5/62-5/86

Claims (3)

(57) [Claims] 1. A region formed of a ferromagnetic thin film and having a concavo-convex pattern corresponding to an information signal and a region where the concavo-convex pattern is not formed are formed on a surface of a disk-shaped substrate in a circumferential direction. Are provided alternately at angular intervals of
A master information carrier, wherein a plurality of through holes are provided in at least a part of a region where the uneven pattern is not formed. 2. A disk-shaped substrate having a surface formed of a ferromagnetic thin film on which a concavo-convex pattern corresponding to an information signal is formed and a region on which the concavo-convex pattern is not formed is provided with a predetermined circumferential direction. Are provided alternately at angular intervals of
The uneven at least a portion the surface height of the shape pattern is not formed region, the master information carrier, wherein the low equalizer Metropolitan than the surface height of the irregularities pattern-formed region. 3. The master according to claim 1, wherein a marker for positioning the master information carrier and a magnetic recording medium for recording an information signal of the master information carrier is arranged. Information carrier.