JPH04324107A - Alignment disk - Google Patents

Abstract

PURPOSE:To simplify the signal processing at the time of automating the inspection/adjustment and to unnecessitate the dedicated track pattern writing machine when the pattern recording is formed. CONSTITUTION:In the same track A with a center of the rotation Qo as the center, an index/burst signal pattern Io, a burst signal pattern AZo for the measurement of azimuth are provided and two inside and outside burst signal patterns 2, 3 which are parallel to each other with the space of 180 degrees in the peripheral direction are provided. These burst signal patterns 2, 3 are formed by the signal pattern having off-set parts 2a, 3a on the outer peripheral side and inner peripheral side of a reference track center line 4, respectively. Thus, since the reproduced output signal of the both burst signal patterns 2, 3 perform the level change toward the same polarity, the eccentricity of the head tracking locus can be detected by comparing with these levels.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alignment disk used for inspecting and adjusting the tracking position of a head in a disk drive.

0002

[Background Art] In order to ensure compatibility between multiple disk drive devices supplied to the market under certain standards, head tracking positions, etc., are inspected during device manufacturing and shipment.
Adjustments are required, and so-called alignment discs are generally used in this inspection and adjustment process.

Conventionally, this type of alignment disk has been constructed as shown in FIG. 3, for example. To explain this based on the same figure, in the same figure, the alignment disk indicated by the reference numeral 20 has an index timing adjustment signal pattern 22 and an azimuth adjustment signal pattern 2 located on the track center line 21 serving as a predetermined reference.
3, and a point Q1 eccentric by a predetermined distance e from the center of rotation Q0.
Two eccentric track patterns 26 and 27 centered on
A record has been created. The diameters r1 and r2 of these eccentric track patterns 26 and 27 are the diameter of the reference track center line 21 as r0, the track width as W, and the track interval as 2c.
Then, r1=r0-(W/2-c) r2=r0+(W/2-c) A burst signal is recorded in each track pattern 26, 27. Further, the azimuth adjustment signal pattern 23 is -β azimuth portion A1, +α azimuth portion A2, −
It consists of an α azimuth portion A3 and a +β azimuth portion A4, and burst signals are recorded in these portions A1 to A4 with azimuth angles of -β, +α, -α, and +β, respectively. The azimuth angle α of the portion A2 (or A3) is set to an angle smaller than the azimuth angle β of the portion A1 (or A4) (|α|<|β|). For example, each part A1~ of the azimuth adjustment signal pattern
The azimuth angle of A4 is -70°, +40°, -40°,
It is set to +70°.

[0004] The alignment disk configured as described above is used as a magnetic head MH of a disk drive (not shown).
FIG. 4 shows the envelope waveform of the output signal when reproduced by. In the figure, a signal waveform D obtained by reproducing each track pattern 26 and 27 is drawn following a portion B corresponding to the index timing adjustment signal pattern 22 and each portion A1 to A4 of the azimuth adjustment signal pattern 23. This signal waveform D has two peak parts Da and Db. These mountain parts Da, D
The levels La and Lb of peaks Pa and Pb of b appear equal to each other (La=Lb) when the magnetic head MH is tracking normally, but when the magnetic head MH is deviated in the radial direction, the levels La and Lb of peaks Pa and Pb appear as shown by the broken line in FIG. Differently as shown (L
a≠Lb) Appears. In this case, the radial deviation amount (so-called off-track amount) Δr of the magnetic head MH is:

00
05]

[Math 1]

It is expressed as: However, Wr and C are the track width and lapping constant of the magnetic head MH, respectively. In the case of a 3.5-inch micro-floppy disk of 135 TPI (tracks per inch) type, the standard values of Wr and C are 130 μm and 20 μm, respectively.

[0007]

By the way, in the conventional alignment disk, the output signals of the eccentric track patterns 26 and 27 are reproduced as a waveform having two mountain portions Da and Db as shown in FIG. Because of this, the waveform shape of each peak portion was unstable. As a result, when automating inspections and adjustments, waveform seeking for detecting peak positions becomes difficult and complex signal processing becomes necessary.

Also, two eccentric track patterns 26
, 27 are arranged concentrically around a point Q0 that is eccentric from the center of rotation Q0, making it difficult to record a signal pattern, which not only increases manufacturing costs but also requires a dedicated track/pattern writing machine. There was also the problem of becoming

Furthermore, two eccentric track patterns 2
Since the area of the eccentric track patterns 6 and 27 occupies most of the area of each track, the area occupied by the eccentric track patterns 26 and 27 relative to the disk area becomes large, which is not only unsuitable for a disk with high recording density. This has the disadvantage that the signal is detected over the entire circumference of the track, which increases the influence of modulation on the disc itself.

The present invention was made in view of the above circumstances, and it not only simplifies signal processing when automating inspection and adjustment, but also eliminates the need for a dedicated track/pattern writing machine when forming a record of a signal pattern. This provides an alignment disk that will

[0011]

[Means for Solving the Problems] An alignment disk according to the present invention provides an index burst signal pattern and an azimuth measurement burst signal pattern on the same track centered on the disk rotation center, and also includes:
In addition to these two signal patterns, there are two inner and outer burst signal patterns arranged at approximately 90° intervals in the circumferential direction and parallel to each other at 180° intervals in the circumferential direction, and the inner burst signal pattern is arranged along the reference track center line. The burst signal pattern on the outer periphery side is formed by a signal pattern having an offset portion on the inner periphery side of the reference track center line.

0012

[Operation] In the present invention, since the reproduction output signals of two burst signal patterns corresponding to each other at an angle of 180° change in level in the direction of the same polarity, the eccentricity of the head tracking trajectory is determined by comparing these levels. can be detected.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the structure of the present invention will be explained in detail with reference to embodiments shown in the drawings.

FIG. 1 is a plan view schematically showing an alignment disk according to the present invention. In the same figure, the reference numeral 1 is an alignment disk, each of which is parallel to the other at an interval of 180° in the circumferential direction on the same track A centered on the disk rotation center Q0, and between the disk rotation center Q0 and this center Q0. Two inner and outer burst signal patterns 2 and 3 are provided on extension lines Q0X0 and Q1X1 of the line Q0Q1 connecting the more eccentric point Q1. Both of these burst signal patterns 2 and 3 are part of a track with a center Q0 and a track diameter r0, and the pattern circumferential dimension is set by a common line passing through a point Q1 eccentric by e from the disk rotation center Q0. There is.

Of these, the inner burst signal pattern 2 is formed by a signal pattern having an offset portion 2a and a pattern center line 2b on the outer and inner sides of the reference track center line 4, respectively. The burst signal pattern 3 is formed by a signal pattern having an offset portion 3a and a pattern center line 3b on the inner and outer circumferential sides of the reference track center line 4, respectively.

Further, on the reference track center line 4 of the track A of the alignment disk 1, burst signal patterns 2 and 3 are arranged in the vicinity of a line Q0Y0 at an interval of approximately 90° in the circumferential direction. An index burst signal pattern I0 for determining the reference angular position or reference level of the index burst signal pattern I0, and an azimuth measurement signal adjacent to the index burst signal pattern I0 in the head scanning direction for inspecting and adjusting the azimuth angle of the magnetic head MH. A burst signal pattern AZ0 is provided.

Note that the pattern offset amount of each burst signal pattern 2 and 3 in the figure is (Wr/2) where the pattern width and wrapping constant are Wr and C, respectively.
-C) is set to the offset amount.

The alignment disk 1 constructed as described above is mounted on a magnetic head M of a disk drive device (not shown).
When reproduced by H, the index and
A signal waveform can be obtained in which the outputs of the timing adjustment signal pattern I0, the azimuth measurement burst signal pattern AZ0, and the internal and external burst signal patterns 3 and 2 are sequentially displayed.

Among these, the levels LA and LB of the reproduced output signals of the burst signal patterns 3 and 2 change in the same polarity direction.

Therefore, in this embodiment, when detecting the off-track amount of the magnetic head MH, that is, the eccentricity of the head tracking locus, the levels LA and LB of the reproduced output signals of both burst signal patterns 2 and 3 are compared. This eliminates the need for peak position detection when automating inspections and adjustments.

Furthermore, in this embodiment, the same track A
By providing the index burst signal pattern I0, the azimuth measurement burst signal pattern AZ0, and the two inner and outer burst signal patterns 2 and 3, pattern recording formation can be simplified.

Furthermore, in this embodiment, the levels LA and L of the reproduced output signals of the internal and external burst signal patterns 2 and 3 are
The fact that the eccentricity of the head tracking trajectory can be detected by comparing B is that it is possible to detect the eccentricity of the head tracking trajectory by comparing
, 27 can also be obtained which is compatible with the disc on which the discs are recorded.

Furthermore, in this embodiment, the fact that both burst signal patterns 2 and 3 are provided at intervals in the circumferential direction on the same track means that these burst signal patterns 2,
The area occupied by the third disk does not become large, and it is not necessary to detect signals over the entire circumference of the track.

[0024] The size of each signal pattern in the present invention is not particularly limited, and it goes without saying that it can be set to any size as necessary.

[0025]

As explained above, according to the present invention, an index burst signal pattern and an azimuth measurement burst signal pattern are provided on the same track centered on the disk rotation center, and both signal patterns and the circumferential direction are provided. There are two inner and outer burst signal patterns arranged at approximately 90° intervals and parallel to each other at 180° intervals in the circumferential direction, and the inner burst signal pattern has an offset portion on the outer circumferential side of the reference track center line. Since the outer burst signal pattern is formed by a signal pattern with an offset part on the inner circumference side of the reference track center line, the level of the reproduced output signal of the two inner and outer burst signal patterns is the same. The polarity will change.

Therefore, when detecting the eccentricity of the head tracking trajectory, it is sufficient to compare the levels of the reproduced output signals of both the internal and external burst signal patterns, which eliminates the need for peak position detection when automating inspection and adjustment. Signal processing can be simplified.

Furthermore, by providing an index burst signal pattern, a burst signal pattern for azimuth measurement, and two internal and external burst signal patterns on the same track, it is possible to simplify pattern recording formation and reduce manufacturing costs. This also eliminates the need for a dedicated track/pattern writing machine when forming pattern records.

Furthermore, the ability to detect the eccentricity of the head tracking locus by comparing the levels of the reproduced output signals of both the internal and external burst signal patterns is compatible with disks on which conventional eccentric track patterns are recorded. Since the disk can be obtained, current manufacturing adjustment and inspection equipment can be used during inspection and adjustment.

In addition, providing the burst signal patterns on the same track at intervals from each other in the circumferential direction is ideal for discs with high recording density because the area occupied by these burst signal patterns with respect to the disc area does not become large. Furthermore, since it is no longer necessary to detect signals over the entire circumference of the track, there is also the advantage that the influence of modulation on the disc itself is reduced.

[Brief explanation of drawings]

FIG. 1 is a plan view schematically showing an alignment disk according to the present invention.

FIG. 2 is a waveform diagram showing a reproduced output waveform obtained by reproducing the alignment disk according to the present invention.

FIG. 3 is a plan view schematically showing a conventional alignment disk.

FIG. 4 is a waveform diagram showing a reproduced output waveform obtained by reproducing a conventional alignment disk.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Alignment disk, 2... Burst signal pattern, 2a... Offset part, 3... Burst signal pattern,
3a...Offset portion, 4...Reference track center line, I0...
Index burst signal pattern, AZ0... Burst signal pattern for azimuth measurement, Q0... Center of disk rotation, Q0X0, Q1X1... Extension line.

Claims (1)

[Claims] 1. An index burst signal pattern and an azimuth measurement burst signal pattern are provided on the same track centered on the center of disk rotation, and
In addition to these two signal patterns, there are two inner and outer burst signal patterns arranged at approximately 90° intervals in the circumferential direction and parallel to each other at 180° intervals in the circumferential direction. The signal pattern is formed by a signal pattern having an offset portion on the outer circumference side of the reference track center line, and the burst signal pattern on the outer circumference side is formed by a signal pattern having an offset portion on the inner circumference side of the reference track center line. Features an alignment disc.