JPH1011743A - Magnetic disc and magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To narrow down the track pitch and to make a magnetic disk device have a large recording capacity by forming patterns of the ruggedness part so that data between adjacent tracks are orthogonally crossing each other. SOLUTION: Data pattern DP is arranged so that an orthogonal phase relation is resulted between adjacent tracks. By this constitution, a PLL is frequency-locked by a signal from a burst pattern and when the phase of a pattern succeeding to the burst pattern is equal, the lock of the PLL is not released. When a magnetic head 8 enters into this data zone, the lock phase of the PLL is changed with the phase of data and the PLL becomes a phase locked state and stabilized. As a result, when data in accordance with the clock are reproduced, data whose phase is not matched with the phase of the clock can be precluded. Then, even when crosstalk between adjacent tracks is present, when a signal level to be reproduced is high, the signal is reproduced without any problem. Thus, the track pitch can be set small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read-only magnetic disk on which data and programs are reproduced by a magnetic head mounted on a flying type head slider, and a magnetic disk device having the magnetic disk. is there.

[0002]

2. Description of the Related Art For example, in a computer system, a hard disk device is used as a magnetic disk device. In recent years, it has been desired to increase the recording capacity of a hard disk drive. To achieve this, a data recording area (hereinafter, referred to as a data zone) composed of uneven portions on both surfaces of a magnetic disk and a control signal recording area (hereinafter, referred to as a data zone). , Servo zones) are formed radially, that is, a so-called pre-emboss type magnetic disk has been proposed.

[0003] The data zone and the servo zone are transferred and formed on the surface between the outer peripheral edge and the inner peripheral edge of the substrate by a stamper attached to a molding die when the ring-shaped substrate is injection-molded. You. Therefore, it is possible to form a read-only magnetic disk in which the digital data itself is formed collectively. Here, the data zone has a concentric circular data pattern for recording data and the like.
Are formed so as to form concave and convex portions, and guard bands for separating adjacent tracks are formed so as to form concave portions. In the servo zone, a burst pattern serving as a reference when generating a servo clock, a header pattern for identifying the servo zone, an address pattern for identifying a track, and a magnetic head are tracked. A fine pattern or the like (hereinafter, referred to as a servo pattern) for control is formed so as to be a convex portion or a concave portion.

[0004]

In the conventional pre-emboss type read-only magnetic disk described above, the minimum pattern length of the data zone is generally determined by the limit of the injection molding of the substrate or the mastering of the stamper. . Therefore, it is difficult to increase the recording capacity of the magnetic disk by increasing the linear recording density.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a read-only magnetic disk capable of increasing the recording capacity and a magnetic disk device provided with the magnetic disk.

[0006]

According to the present invention, there is provided a magnetic disk in which data and the like are reproduced by a magnetic head mounted on a flying type head slider, the concave and convex formed on the surface. In a magnetic disk which is radially divided into a data recording area and a control signal recording area by a portion, the pattern of the concave and convex portions is formed such that the data phases between adjacent tracks are orthogonal to each other. This is achieved by:

[0007] According to the above configuration, since the data phases between adjacent tracks are configured to be orthogonal to each other, the reproduction crosstalk between adjacent tracks can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The embodiments described below are preferred specific examples of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. It is not limited to these forms unless otherwise stated.

FIG. 1 is a perspective view showing a configuration example of a hard disk drive which is an embodiment of the magnetic disk drive of the present invention. The hard disk drive 1 is provided with a spindle motor 9 disposed behind a plane portion of a housing 2 formed of an aluminum alloy or the like, and a magnetic disk 3 driven to rotate at a constant angular velocity by the spindle motor 9. Have been. Further, an arm 4 is attached to the housing 2 so as to be swingable around a vertical axis 4a. A voice coil 5 is attached to one end of the arm 4, and a head slider 6 is attached to the other end of the arm 4. Magnets 7a and 7b are mounted on the housing 2 so as to sandwich the voice coil 5. Voice coil 5 and magnets 7a and 7b
Thus, a voice coil motor 7 is formed.

In such a configuration, the voice coil 5
When an electric current is supplied from the outside to the arm 4, the arm 4 rotates around the vertical axis 4a based on the force generated by the magnetic fields of the magnets 7a and 7b and the electric current flowing through the voice coil 5. Thereby, the head slider 6 attached to the other end of the arm 4 moves as shown by an arrow X in FIG.
The magnetic disk 3 moves substantially in the radial direction. Therefore, the magnetic head 8 mounted on the head slider 6
(See FIG. 3) performs a seek operation on the magnetic disk 3 and reproduces data and the like on a predetermined track or the like of the magnetic disk 3.

As shown in FIG. 3, the head slider 6 has rails 6a and 6b acting as air bearing surfaces on both sides of the lower surface thereof, and the air inflow ends of the rails 6a and 6b. Are formed with tapered portions 6c and 6d. Thus, when the head slider 6 approaches the surface of the rotating magnetic disk 3, the levitation force is increased by the airflow flowing between the rails 6 a and 6 b and the surface of the magnetic disk 3 with the rotation of the magnetic disk 3. receive. The head slider 6
In addition, the magnetic head 8 flies and travels from the surface of the magnetic disk 3 at a small interval (floating amount).

FIG. 4 is a plan view showing an embodiment of a magnetic disk according to the present invention, FIG.
FIG. 2B is a sectional structural view in the circumferential direction. A data recording area (data zone) and a control signal recording area (servo zone) each having an uneven portion are formed radially on a substrate 31 of the magnetic disk 3 made of synthetic resin, glass, aluminum, or the like. A magnetic film 32 is formed.

That is, in the data zone, a concentric data pattern DP for recording data or the like is formed so as to form an uneven portion, and a guard band GB for separating adjacent tracks is formed in a concave portion. It is formed so that it becomes. In the servo zone, a burst pattern serving as a reference when generating a servo clock, a header pattern for identifying a servo zone, an address pattern for identifying a track, and a magnetic head 8 are provided. The servo pattern SP such as a fine pattern for tracking control is formed so as to be a convex portion or a concave portion.

FIG. 6 is a block diagram showing a configuration example of a control unit of the hard disk device 1 shown in FIG. 1 incorporating the magnetic disk 3 shown in FIG. The reproduction amplifier 11 of the control unit 10 amplifies the reproduction signal from the magnetic head 8 and outputs the amplified signal to the peak detection circuit 12. The peak detection circuit 12 detects a peak of the amplitude based on the reproduction signal from the reproduction amplifier 11 and outputs the detected peak to the PLL 13, the pattern discrimination circuit 14, and the data reproduction circuit 15.

The PLL 13 determines the clock phase based on the peak of the amplitude of the reproduced signal from the peak detection circuit 12. When the pattern discrimination circuit 14 identifies the servo zone based on the peak of the amplitude of the reproduction signal from the peak detection circuit 12, the pattern discrimination circuit 14 outputs the servo zone identification signal to the timing control circuit 16
Output to The timing control circuit 16 outputs to the data reproduction circuit 15 a timing signal for specifying each pattern of the reproduction signal based on the servo zone identification signal from the pattern discrimination circuit 14. The data reproduction circuit 15 receives the timing signal from the timing control circuit 17 and the PLL 13
The data is reproduced by the peak of the amplitude of the reproduction signal from the peak detection circuit 12 in accordance with the clock phase from.

Here, for comparison, signal processing of a pre-emboss type write / read magnetic disk will be described by taking a sector servo method as an example. In the servo zone of the write / read magnetic disk, for example, a servo pattern SP as shown in FIG. 7 is provided. First, a PLL (Phase-Locked L) is generated by a simple repetition signal from a burst pattern.
oop) is pulled in, and the subsequent clock phase is determined. Then, a signal from the header pattern is detected based on this clock, and the servo zone is identified.

As a result, it is determined that the subsequent patterns are the address code pattern and the fine pattern. That is, a timing signal is generated using a clock, and position information of an absolute position on the magnetic disk is obtained from signals from the address code pattern and the fine pattern according to the timing signal.
Then, the magnetic head 8 is positioned using the position information.

On the other hand, recording and reproduction of data are performed in the following procedure. For example, a sector for recording data as shown in FIG. 8 exists on one circumference of a track of the data zone of the magnetic disk for writing / reading, and data recording / reproduction is performed in units of this sector. First, a PLL used for data reproduction is pulled in the preamble portion, and the subsequent clock phase is determined. Then, a timing signal is generated based on this clock, and the position of the data zone is determined.

Thereafter, the timing is extracted from the edge of the read data signal, the PLL is phase-locked thereto, and the data is reproduced based on this clock. The timing chart of this data reproduction is as shown in FIG. 9, and the lock phase of the PLL fluctuates following the data phase fluctuation. At the time of reproduction, the preamble signal and the data signal are written based on the same clock. Since such a procedure is taken, it is impossible to manage the phase relationship between adjacent tracks in the magnetic disk for writing / reading in consideration of the rotation unevenness of the magnetic disk and the like.

On the other hand, in the read-only magnetic disk 3 shown in FIG. 4, the phases of clocks used for data reproduction between adjacent tracks are arranged in an orthogonal relationship. The data has different information points depending on the modulation method, but here, a description will be given taking a normal peak detection as an example. In the case of peak detection, there is information at the peak point of the reproduced data, that is, at the edge of the formed pattern. Therefore, the data patterns may be arranged so that the phases of the edges are orthogonal to each other between adjacent tracks. Also, patterns provided for clock recovery for reproducing data may be arranged so as to have a quadrature phase relationship between adjacent tracks.

For example, FIG. 10 is a plan view showing an example of a data pattern DP arranged so as to have a quadrature phase relationship between adjacent tracks. Other patterns have a normal phase relationship (the same phase). In such a configuration, the frequency of the PLL is locked by a signal from the burst pattern. If the phase of the pattern following the burst pattern is the same, the lock of the PLL is not released. When the magnetic head 8 enters this data zone, the lock phase of the PLL changes according to the phase of the data, and the phase is locked and stabilized.

Since the pattern is created so that the phase of the data is constant within one track, the PLL can be kept on the track without any disconnection, and the clock can be continuously supplied. Therefore, if data is reproduced according to the clock, data that does not match the phase of the clock can be eliminated. Even if there is crosstalk between adjacent tracks, reproduction can be performed without any problem if the signal level to be reproduced is high. Therefore, the track pitch can be set smaller than that of the magnetic disk for writing / reading.

Further, the VCO output signal of the PLL locked by the signal from the burst pattern is used as a clock,
Play the subsequent pattern. At this time, the lock phase of the PLL is determined by the phase of the signal from the burst pattern. Therefore, if the phase of a signal from a burst pattern to be a reference is orthogonal between adjacent tracks, the phase of a clock for data reproduction also has an orthogonal relationship. Therefore,
Even if the data signal of the adjacent track is mixed due to crosstalk, the data phase differs from the original data phase, so that it is not necessary to adopt the data as data.

For example, FIG. 11 is a plan view showing an example of a data pattern DP, a burst pattern, a header pattern, and an address code pattern arranged so as to have a quadrature phase relationship between adjacent tracks. The fine patterns have a normal phase relationship (the same phase). In such a configuration, P
LL locks both phase and frequency. At this phase, all the predetermined tracks can be reproduced. In this case,
All patterns on a given track, including each pattern in the servo zone, must have a constant phase.

In an actual system, the threshold level of the peak detection circuit is often set to about 30% of the reproduced signal amplitude. Therefore, if the amplitude of the analog signal is sufficiently small with respect to this level, even if there is crosstalk, there is obtained a signal having no problem in data reproduction signal quality. Since mixing of about 20% in the analog detection level can be tolerated without any problem, the allowable level of total crosstalk can be tolerated in the order of 25 dB.
Judging from the fact that it is about 35 dB, the allowable value becomes large.

The above-mentioned magnetic disk 3 can be manufactured using optical technology, and the manufacturing method will be described with reference to FIGS. First, the surface of the glass master 41 is coated with, for example, a photoresist 42. The glass master 41 coated with the photoresist 42 is mounted on a turntable 43 and rotated. For example, only a portion of the photoresist 42 which forms a concave portion is irradiated with a laser beam 44 to perform pattern cutting. After irradiating the laser beam 44, the photoresist 42 is developed to remove the exposed portion of the photoresist 42. Nickel 4 is applied to the surface of the glass master 41 from which the exposed portions of the photoresist 42 have been removed.
5 is plated. The nickel 45 is peeled off from the glass master 41 to form a stamper 46.

Next, the substrate 31 is formed using the stamper 46. Then, a magnetic film 32 is formed on the surface of the substrate 31 by sputtering or the like to form the magnetic disk 3. Then, the magnetic disk 3 is magnetized by the following method.
The magnetic disk 3 is set on the magnetizing device 47, and is rotated and driven in the direction indicated by the arrow a in FIG. And FIG.
As shown in (A), while applying the first DC current to the magnetizing magnetic head 48, the magnetizing magnetic head 48 is moved at a track pitch in the radial direction on the magnetic disk 3 so that the magnetic disk 3 The magnetic films 32 in the convex and concave portions are once magnetized in the same direction. Then, as shown in FIG.
While applying a second DC current having a polarity opposite to that of the first DC current and a current value smaller than that of the first DC current to the magnetization magnetic head 48, the magnetization magnetic head 48 is
The magnetic disk 32 is moved in the upper radial direction at a track pitch, and only the magnetic film 32 of the convex portion of the magnetic disk 3 is magnetized in the opposite direction to write data and positioning signals.

[0028]

As described above, according to the present invention,
Since the reproduction crosstalk between adjacent tracks can be reduced, the track pitch can be narrowed to increase the recording capacity.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration example of a hard disk drive which is an embodiment of a magnetic disk drive of the present invention.

FIG. 2 is an exemplary perspective view showing an operation example of a head slider of the hard disk device shown in FIG. 1;

FIG. 3 is an exemplary perspective view showing a detailed example of a head slider of the hard disk device shown in FIG. 1;

FIG. 4 is a plan view showing an embodiment of the magnetic disk of the present invention.

5A and 5B are a sectional view in a radial direction and a sectional view in a circumferential direction of the magnetic disk shown in FIG. 4;

6 is a block diagram showing a configuration example of a control unit of the hard disk device shown in FIG.

FIG. 7 is a plan view showing a detailed example of a magnetic disk for writing / reading.

FIG. 8 is a plan view showing a configuration example of a servo sector of the magnetic disk shown in FIG. 7;

FIG. 9 is a time chart showing data reproduction on the magnetic disk shown in FIG. 7;

FIG. 10 is a plan view showing a first embodiment of the details of the magnetic disk shown in FIG. 4;

FIG. 11 is an exemplary plan view showing details of a second embodiment of the magnetic disk shown in FIG. 4;

FIG. 12 is a first view for explaining a method of manufacturing the magnetic disk shown in FIG. 4;

FIG. 13 is a second diagram illustrating the method for manufacturing the magnetic disk shown in FIG. 4;

FIG. 14 is a third diagram illustrating the method for manufacturing the magnetic disk shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hard disk device, 2 ... Housing, 3 ...
Magnetic disk, 4 ... arm, 4a ... vertical axis, 5
... voice coil, 6 ... head slider, 6a
..Rail, 6b ... rail, 6c ... tapered part,
6d: tapered portion, 7: voice coil motor, 7
a: magnet, 7b: magnet, 8:
Magnetic head, 9 ... motor, 10 ... control unit, 11
... Regenerative amplifier, 12 ... Peak detection circuit, 13
..PLL, 14 ... Pattern discrimination circuit, 15 ...
Data reproduction circuit, 16 ... timing control circuit, 31
... substrate, 32 ... magnetic film, 41 ... glass master, 42 ... photoresist, 43 ... turntable, 44 ... laser light, 45 ... nickel, 46
... Stamper, 47 ... Magnetizing device, 48 ... Magnetic head

Claims (4)

[Claims] 1. A magnetic disk on which data and the like are reproduced by a magnetic head mounted on a flying type head slider, wherein a data recording area and a control signal recording area are radially divided by irregularities formed on the surface. A magnetic disk according to claim 1, wherein the patterns of the concave and convex portions are formed such that the data phases between adjacent tracks are orthogonal to each other. 2. The magnetic disk according to claim 1, wherein an area where the pattern of the uneven portion is formed is the data recording area. 3. The magnetic disk according to claim 1, wherein the pattern forming regions of the concave and convex portions are the data recording region and the control signal recording region. 4. A magnetic disk which is radially divided into a data recording area and a control signal recording area by an uneven portion formed on the surface, and floats on the surface of the magnetic disk and moves in the radial direction of the magnetic disk. And a magnetic head mounted on the head slider and reproducing data and the like on the magnetic disk, wherein the pattern of the concave and convex portions is formed by the data between adjacent tracks. A magnetic disk drive formed so that data phases are orthogonal to each other.