JP2000173047A - Magnetic recording medium and method for writing servo signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate writing of a servo signal onto a magnetic recording medium. SOLUTION: A magnetic recording medium 4 is fabricated by forming a magnetic recording layer on a plastic substrate. In this case, a concave-and- convex pattern (a pit train 9) is formed on the plastic substrate so as to correspond to a predetermined clock pattern. When a servo signal is then written onto the magnetic recording medium 4, the pit train 9 is detected by an optical pickup 52 to generate a clock signal, and the servo signal is written by a magnetic head 8 onto the magnetic recording medium 4 with the thus-obtained clock signal being taken as reference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a magnetic recording medium having a magnetic recording layer formed on a plastic substrate. The present invention also relates to a method for writing a servo signal on such a magnetic recording medium.

[0002]

2. Description of the Related Art In order to reduce the size and capacity of a magnetic recording medium, it is necessary to improve the positioning accuracy (that is, tracking accuracy) of a magnetic head used for recording and reproducing on the magnetic recording medium. Therefore, for example, in a hard disk drive, a servo signal previously written on a magnetic recording medium as a signal for positioning the magnetic head is read by the magnetic head during recording and reproduction, and the position of the magnetic head is controlled based on the servo signal. A tracking servo system for positioning a magnetic head at the center of a recording track is employed.

In adopting such a tracking servo method, it is necessary to write servo signals with high precision in advance on a magnetic recording medium mounted on a hard disk device. Conventionally, writing of a servo signal to a magnetic recording medium is performed using a device called a servo writer as shown in FIG.

[0004] As shown in FIG.
A head feed mechanism 102 capable of operating a head arm 101 attached to the hard disk device 100 with high accuracy, and a clock magnetic head 103 for writing and reading a clock signal for servo writing are provided.

When writing a servo signal to the magnetic recording medium 104, the servo signal is written to the magnetic recording medium 104 by the magnetic head 105 mounted on the hard disk device 100, and the writing position is set to a high level using a servo writer. Control to accuracy.

Specifically, first, the head feed mechanism 102
To control the position of the magnetic head 105 in the radial direction of the magnetic recording medium 104 with high accuracy. That is, when writing a servo signal, the head feed mechanism 102
Managed by

Further, among the write positions of the servo signal,
The circumferential direction of the magnetic recording medium 104 is managed by a servo write clock signal. Specifically, first, before writing the servo signal to the magnetic recording medium 104,
Clock magnetic head 10 provided in servo writer
In step 3, the clock information 106 for one round of the magnetic recording medium is written on the magnetic recording medium 104. When writing a servo signal to the magnetic recording medium 104, the clock information 10 previously written to the magnetic recording medium 104 is used.
6 is reproduced by the clock magnetic head 103 provided in the servo writer. Then, a clock signal is generated based on the reproduced waveform, and a servo signal writing position in the circumferential direction is specified based on the clock signal,
Magnetic head 10 mounted on hard disk drive 100
5 writes a servo signal to the magnetic recording medium 104.

[0008]

In order to write a servo signal as shown in FIG.
3 requires writing and reading of the clock information 106. The clock magnetic head 103 is the same as the magnetic head 105 mounted on the hard disk device 100. To write and read the clock information 106 with the clock magnetic head 103, the clock magnetic head 103 is used. It is necessary to fly the magnetic recording medium 104 stably with a flying height of several tens of nm. Therefore, in the conventional servo writer, high-accuracy position adjustment is required for mounting the clock magnetic head 103 and adjusting the height (Z-Height).

In order to write and read clock information 106 using the clock magnetic head 103, the clock magnetic head 103 must be connected to the magnetic recording medium 10.
4 and a mechanically complicated mechanism such as an unloading mechanism for ejecting the clock magnetic head 103 from above the magnetic recording medium 104.

Further, when loading the clock magnetic head 103 onto the magnetic recording medium 104 or unloading the clock magnetic head 103 from above the magnetic recording medium 104, the clock magnetic head 103 may be used.
May come into contact with the magnetic recording medium 104 and damage the magnetic recording medium 104, making the magnetic recording medium 104 unusable.

As described above, in the servo signal writing method as shown in FIG.
There were various problems arising from the use of

The present invention has been proposed in view of such conventional circumstances, and a magnetic recording medium capable of writing a servo signal without using a clock magnetic head, and a clock magnetic head. It is an object of the present invention to provide a servo signal writing method capable of writing a servo signal on a magnetic recording medium without using a servo signal.

[0013]

A magnetic recording medium according to the present invention is a magnetic recording medium in which a magnetic recording layer is formed on a plastic substrate, wherein the plastic substrate has an uneven pattern corresponding to a predetermined clock pattern. Is formed.

In this magnetic recording medium, a concavo-convex pattern corresponding to a predetermined clock pattern is formed on a plastic substrate. By optically detecting the concavo-convex pattern, it is possible to use a clock magnetic head without using a clock magnetic head.
A clock signal can be obtained.

Further, in the servo signal writing method according to the present invention, when writing a servo signal on a magnetic recording medium having a magnetic recording layer formed on a plastic substrate, an uneven pattern corresponding to a predetermined clock pattern is formed on the plastic substrate. It is formed in advance. Then, a clock signal is generated by detecting the concavo-convex pattern with an optical pickup, and a servo signal is written to a magnetic recording medium by a magnetic head based on the clock signal.

In this servo signal writing method, a concavo-convex pattern corresponding to a predetermined clock pattern is formed on a plastic substrate in advance, and a clock signal is generated by detecting the concavo-convex pattern with an optical pickup. Therefore, according to the servo signal writing method, the servo signal can be written based on the clock signal without using the clock magnetic head.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, FIG. 1 shows an example of the configuration of a hard disk drive equipped with a magnetic recording medium to which the present invention is applied. The hard disk drive 1 includes a spindle motor 3 mounted on a pedestal 2, a disk-shaped magnetic recording medium 4 driven to rotate by a spindle motor 4, a voice coil motor 5 mounted on the pedestal 2, and a voice coil motor 5. Head arm 6 to be moved and head suspension 7 attached to the tip of head arm 6
And a magnetic head 8 attached to the tip of a head suspension 7.

When the hard disk drive 1 is used, the magnetic recording medium 4 is driven to rotate by the spindle motor 3. Then, recording and reproduction are performed on the rotating magnetic recording medium 4 by the magnetic head 8. At this time, the head arm 6 is moved by the voice coil motor 5 to the magnetic recording medium 4.
By moving the magnetic head 8 in the radial direction, the magnetic head 8 is moved to a desired recording / reproducing position.

In the hard disk drive 1, the magnetic recording medium 4 is used as a signal for positioning the magnetic head 8.
The servo signal is written in advance. At the time of recording / reproducing on the magnetic recording medium 4, the servo signal is read from the magnetic recording medium 4 by the magnetic head 8, and the position of the magnetic head 8 is controlled based on the servo signal, so that the magnetic head 8 Position so that it is positioned.

The magnetic recording medium 4 mounted on the hard disk drive 1 is a magnetic recording medium to which the present invention is applied, and has a pit row 9 which is an uneven pattern corresponding to a predetermined clock pattern.

FIG. 2 is a plan view of the magnetic recording medium 4. FIG. 3 is an enlarged view of a portion B in FIG. The magnetic recording medium 4 is a magnetic recording medium in which a magnetic recording layer 12 is formed on a plastic substrate 11 as shown in FIG. 3, and an annular magnetic recording area A is formed as shown in FIG. Have. The magnetic recording area A is an area where magnetic recording is performed, and includes a data zone 13 where an arbitrary data is written and a servo zone 14 where a servo signal is written.

The servo signal is written at a predetermined location in the magnetic recording area A at regular intervals for each sector. As a result, each servo zone 14 moves along the trajectory when the magnetic head 8 is moved by the head arm 6.
The magnetic recording area A is an arc-shaped area extending from the inner side to the outer side. That is, the data zone 13 and the servo zone 14 are formed substantially radially from the center of the magnetic recording medium 4.

In the servo zone 14, for example, servo signals having a pattern as shown in FIG. 3 are written. FIG. 3 shows an example in which the servo signal pattern includes a burst section 21, an address section 22, and a fine pattern section 23. Here, a burst signal used for auto gain control or the like is recorded in the burst section 21. In the address section 22, track position information indicating the position of the recording track in the radial direction of the magnetic recording medium 4 is recorded. In the fine pattern section 23, a signal for tracking control is recorded. On the other hand, as shown in FIG. 3, a data track 24 is formed in the data zone 13, and arbitrary data is recorded on the data track 24.

In the magnetic recording medium 4, a pit row 9 for one round of the disk is formed outside the magnetic recording area A. The pit row 9 is formed as a concavo-convex pattern corresponding to a predetermined clock pattern.
It is formed in. That is, the magnetic recording medium 4 has a magnetic recording layer 12 formed on a plastic substrate 11 on which a concavo-convex pattern corresponding to a predetermined clock pattern is formed in advance.

The pit row 9 is used when writing a servo signal on the magnetic recording medium 4. That is, when writing a servo signal to the magnetic recording medium 4,
As will be described later, the pit row 9 is detected by an optical pickup, a clock signal is generated based on the detection result, and a servo signal writing position in the circumferential direction is specified based on the clock signal, and the hard disk drive is determined. A servo signal is written on the magnetic recording medium 4 by the magnetic head 8 mounted on the magnetic recording medium 4.

In the magnetic recording medium 4, the pit row 9 which is a concave and convex pattern corresponding to a predetermined clock pattern is formed on the outer peripheral side of the magnetic recording area A. Any location other than the magnetic recording area may be used. For example, it may be formed closer to the inner circumference of the disk than the magnetic recording area A.

When manufacturing the magnetic recording medium 4 as described above, for example, the plastic substrate 11 is formed by injection molding using an injection molding technique used for an optical disk or the like. Then, the magnetic recording layer 12 is formed on the plastic substrate 11. A specific example of such a manufacturing method will be described with reference to FIGS.

When the magnetic recording medium 4 is manufactured, first, a stamper serving as a master of the plastic substrate 11 is manufactured by a mastering process. In this mastering step, first, as shown in FIG. 4, a glass master disk 31 is prepared and its surface is polished. Next, as shown in FIG. 5, a resist 32 is applied to the surface of the glass master 31 subjected to the polishing treatment.

Next, as shown in FIG. 6, laser cutting is performed to form a latent image corresponding to the clock pattern on the resist 32. That is, the laser beam L modulated so as to correspond to the clock pattern is applied to the resist 32 while the glass master 31 coated with the resist 32 is mounted on the turntable 33 and rotated by the spindle motor 34.
Irradiation. As a result, a latent image corresponding to the clock pattern is formed on the resist 32. Then, resist 3
Develop 2. Thereby, a concavo-convex pattern corresponding to the clock pattern is formed.

Next, as shown in FIG. 7, a plating layer 35 made of Ni or the like is formed on the surface on which the uneven pattern is formed. Thereafter, as shown in FIG.
Is peeled off, and the peeled plating is washed with acetone or the like to remove the resist remaining on the surface on which the concavo-convex pattern has been transferred. As a result, a stamper made of plating to which the uneven pattern is transferred is obtained.

Next, as shown in FIG. 9, the stamper 40 manufactured as described above is attached to a mold 41. Here, on the stamper 40, an uneven pattern 40a formed by transferring the uneven pattern formed on the resist 32 is formed. The uneven pattern 40a is an uneven pattern corresponding to the clock pattern.
Is formed at a position corresponding to the outside of the magnetic recording area A so as to correspond to the pit row 9 for one round of the disk.

Next, injection molding is performed by using a mold to which the stamper 40 is attached, and a plastic substrate 11 is manufactured. As a result, as shown in FIG. 10, a plastic substrate 11 in which a pit array 9 for one round of the disk is formed outside the magnetic recording area A as an uneven pattern corresponding to the clock pattern is obtained. In addition, as a material of the plastic substrate 11, specifically, polymethyl methacrylate, polycarbonate, or the like is preferable.

Finally, a magnetic recording layer 12 is formed on the plastic substrate 11 obtained as described above. As a result, a magnetic recording medium 4 in which a pit array 9 for one round of the disk is formed outside the magnetic recording area A as a concavo-convex pattern corresponding to the clock pattern is obtained.

The magnetic recording medium 4 manufactured as described above
Is incorporated in the hard disk drive 1 as shown in FIG. 1, and then a servo writer writes a servo signal. Hereinafter, a method of writing a servo signal will be described with reference to FIG.

Here, as shown in FIG. 11, a head feed mechanism 51 capable of operating the head arm 6 attached to the hard disk drive 1 with high precision, and an optical element for reading a clock signal for servo writing. A servo writer having the pickup 52 is used.

When writing a servo signal to the magnetic recording medium 4, the servo signal is written to the magnetic recording medium 4 by the magnetic head 8 mounted on the hard disk drive 1, and the writing position is set to a high level using a servo writer. Control to accuracy.

Specifically, first, the position of the head arm 6 is operated by the head feed mechanism 51, whereby the position of the magnetic head 8 is controlled with high accuracy in the radial direction of the magnetic recording medium 4. That is, when writing the servo signal, the head feed mechanism 51 manages the writing position in the radial direction of the magnetic recording medium 4.

Further, among the write positions of the servo signal,
The circumferential direction of the magnetic recording medium 4 is managed by a servo write clock signal. This clock signal is
It is generated by detecting a pit row 9 formed in advance on the magnetic recording medium 4.

That is, when a servo signal is written on the magnetic recording medium 4, the pit train 9 formed as a concavo-convex pattern corresponding to the clock pattern is inserted into the optical pickup 52.
To detect. At this time, the optical pickup 52 irradiates the magnetic recording medium 4 with light and detects the reflected light as in the case of reproducing a signal from the optical disk, so that the light spot follows the pit row 9. As described above, while performing the tracking servo and the focusing servo, the pit row 9 formed as an uneven pattern corresponding to the clock pattern is detected. And the optical pickup 5
2, a reproduction signal obtained by detecting the pit string 9 is passed through an amplifier circuit 53, a detection circuit 54, and a PLL circuit 55, and a clock signal is generated from the reproduction signal obtained by detecting the pit string 9. .

When writing a servo signal to the magnetic recording medium 4, the servo signal writing position in the circumferential direction is specified based on the clock signal detected by the optical pickup 52 as described above, and A servo signal is written to the magnetic recording medium 4 by the mounted magnetic head 8.

When the servo signal is written in this manner, the clock magnetic head used in the conventional servo writer becomes unnecessary. This eliminates the need for a highly accurate position adjustment of the clock magnetic head, a load / unload mechanism for the clock magnetic head, and the like, and allows the configuration of the servo writer to be simple and compact.

When a clock magnetic head similar to the magnetic head 8 mounted on the hard disk drive 1 is used, the clock magnetic head is stable on the magnetic recording medium 4 with a small flying height of several tens nm. It is necessary to let it fly. For this reason, when the clock magnetic head is used, the clock magnetic head may contact the magnetic recording medium 4 to damage the magnetic recording medium 4 and render the magnetic recording medium 4 unusable. Was.

On the other hand, when the optical pickup 52 is used, the distance from the magnetic recording medium 4 can be increased. More specifically, when an optical pickup 52 equivalent to that used for a compact disk or the like is used, the distance between the optical pickup 52 and the magnetic recording medium 4 can be set to about 3 mm.
Therefore, the optical pickup 5 is used to generate the clock signal.
By using 2, the possibility of damaging the magnetic recording medium 4 can be greatly reduced as compared with the case where a clock magnetic head is used.

[0045]

As described above in detail, according to the present invention, it is possible to write a servo signal on a magnetic recording medium without using a clock magnetic head. Therefore, according to the present invention, a highly accurate position adjustment of the clock magnetic head and a load / unload mechanism of the clock magnetic head are not required, and the configuration of the servo writer can be made simple and compact. .

In addition, when an optical pickup is used to generate a clock signal, the distance from the magnetic recording medium can be made larger than when a clock magnetic head is used. Therefore, the possibility of damaging the magnetic recording medium can be greatly reduced.

In addition, since the optical pickup has a longer device life than the magnetic head due to its characteristics, the use of the optical pickup for generating the clock signal has a great merit in terms of maintenance of the servo writer. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a configuration of a hard disk device equipped with a magnetic recording medium to which the present invention is applied.

FIG. 2 is a plan view showing an example of a magnetic recording medium to which the present invention has been applied.

FIG. 3 is an enlarged perspective view of a main part schematically showing a specific example of a servo signal pattern written on a magnetic recording medium to which the present invention is applied, and a concavo-convex pattern formed on the magnetic recording medium.

FIG. 4 is a diagram for explaining an example of a method for manufacturing a magnetic recording medium to which the present invention is applied, and is a diagram illustrating a glass master used in a mastering step.

FIG. 5 is a view for explaining an example of a method for manufacturing a magnetic recording medium to which the present invention is applied, and is a view showing a state where a resist is applied to a glass master.

FIG. 6 is a diagram for explaining an example of a method for manufacturing a magnetic recording medium to which the present invention is applied, and is a diagram illustrating a process of forming a latent image corresponding to a clock pattern on a resist by laser cutting.

FIG. 7 is a diagram for explaining an example of a method for manufacturing a magnetic recording medium to which the present invention is applied, and is a diagram showing a state in which a plating layer is formed on an uneven pattern formed by developing a resist. is there.

FIG. 8 is a view for explaining an example of a method for manufacturing a magnetic recording medium to which the present invention is applied, and is a view showing a step of peeling a plating layer.

FIG. 9 is a diagram illustrating an example of a method for manufacturing a magnetic recording medium to which the present invention has been applied, and is a diagram illustrating a process of attaching a stamper to a mold.

FIG. 10 is a diagram for explaining an example of a method for manufacturing a magnetic recording medium to which the present invention is applied, and is a diagram illustrating a plastic substrate obtained by injection molding using a stamper.

FIG. 11 is a diagram showing a state in which a servo signal is written to a magnetic recording medium mounted on a hard disk device by applying the present invention.

FIG. 12 is a diagram for explaining a conventional servo signal writing method.

[Explanation of symbols]

Reference Signs List 1 hard disk drive, 2 pedestals, 3 spindle motor, 4 magnetic recording medium, 5 voice coil motor, 6 head arm, 7 head suspension, 8 magnetic head, 9 pit row, 11 plastic substrate, 12 magnetic recording layer, 13 data zone, 14 Servo zone

Claims (3)

[Claims] 1. A magnetic recording medium comprising a plastic substrate and a magnetic recording layer formed thereon, wherein the plastic substrate has a concavo-convex pattern corresponding to a predetermined clock pattern. recoding media. 2. The method according to claim 1, wherein the plastic substrate is formed in a disk shape, and the concavo-convex pattern is formed on a disk outer circumferential side and / or a disk inner circumferential side with respect to a region where magnetic recording is performed. The magnetic recording medium according to claim 1. 3. When a servo signal is written on a magnetic recording medium having a magnetic recording layer formed on a plastic substrate, an uneven pattern corresponding to a predetermined clock pattern is formed on the plastic substrate in advance. A servo signal writing method, comprising: generating a clock signal by detecting a pattern with an optical pickup; and writing a servo signal to the magnetic recording medium with a magnetic head based on the clock signal.