JPH04324108A - Alignment disk - Google Patents

Abstract

PURPOSE:To simplify the signal processing at the time of automating the inspection/adjustment, to improve the eccentricity detection accuracy and to unnecessitate the dedicated track pattern writing machine at the time of the formation of the pattern recording. CONSTITUTION:In the same track A, a signal patterns Io, AZo are provided and plural pairs of radial signal patterns 2-4 are provided. The radial signal patterns of each pair are formed by the two signal patterns 2a-4a, 2b-4b on the inner and outer peripheral sides. For instance, a signal pattern 2a of the inner peripheral side and a signal pattern 3b of the outer peripheral side, and a signal pattern 2b on the outer peripheral side and a signal pattern 3a on the inner peripheral side are positioned at the parts neighboring with each other in the peripheral direction. Therefore, as the reproduced output signal of the signal pattern on the inner and outer peripheral sides perform the level change toward the same polarity, the eccentricity of the head tracking locus can be detected by comparing 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 of a disk drive device.

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. 5, 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. 6 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 are 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, the eccentric track pattern 26,2
Since the area of pattern 7 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 makes it not only unsuitable for a disk with high recording density, but also This has the disadvantage that the signal is detected over a period of time, which increases the influence of modulation on the disc itself.

Furthermore, since only one set of information can be obtained for the entire circumference of the track as the eccentricity detection information of the tracking locus, there is also the problem that measurement errors increase and the accuracy of eccentricity detection decreases.

The present invention has been made in view of the above circumstances, and it is possible to simplify signal processing when automating inspection and adjustment, improve eccentricity detection accuracy, and use a dedicated system when forming pattern records. The present invention provides an alignment disk that eliminates the need for a track pattern writing machine.

0012

[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:
A plurality of sets of radial signal patterns are arranged in parallel at equal intervals in the circumferential direction, and each set of radial signal patterns is formed by two signal patterns on the inner and outer circumferential sides that are arranged in parallel at intervals of 180° in the circumferential direction, Of the two sets of radial signal patterns adjacent to each other, the signal pattern on the inner circumferential side of one radial signal pattern and the signal pattern on the outer circumferential side of the other radial signal pattern are positioned at positions adjacent to each other in the circumferential direction, Further, the signal pattern on the outer circumferential side of one radial signal pattern and the signal pattern on the inner circumferential side of the other radial signal pattern are positioned at positions adjacent to each other in the circumferential direction.

[0013]

[Operation] In the present invention, since the levels of the reproduction output signals of the two signal patterns on the inner and outer circumferential sides of each set of radial signal patterns change in the direction of the same polarity, these levels are compared to determine the eccentricity of the head tracking trajectory. can be detected.

[0014]

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, and FIG. 2 is a waveform diagram showing a reproduced output waveform obtained by reproducing the alignment disk according to the present invention. In the figure, the reference numeral 1 indicates an alignment disk, and three sets of radial signal patterns 2 to 4 are provided in parallel at equal intervals in the circumferential direction on the same track A centered on the disk rotation center Q0. Each of these sets of radial signal patterns 2 to 4 includes inner signal patterns 2a to 4a having offset portions g1 to g3 and pattern center lines h1 to h3 on the outer and inner circumferential sides of the reference track center line 5, respectively. , this signal pattern 2
signal patterns 2b to 4b on the outer circumferential side, which are arranged at intervals of 180° in the circumferential direction from a to 4a and have offset portions G1 to G3 and pattern center lines H1 to H3 on the inner and outer circumferential sides of the reference track center line 5, respectively; It is formed by.

That is, each set of radial signal pattern 2
-4 are parts of tracks each having a center Q0 and a track diameter r0, and are formed by two signal patterns 2a-4a, 2b-4b on the inner and outer circumferential sides corresponding to each other at an angle of 180°. .

[0017] Each of the two sets of adjacent radial signal patterns 2 and 3 (the same applies to other sets of radial signal patterns) is a signal pattern 2a on the inner circumferential side of one radial signal pattern 2. , the signal pattern 3b on the outer circumferential side of the other radial signal pattern 3 is located at a portion adjacent to each other in the circumferential direction, and the signal pattern 2 on the outer circumferential side of the one radial signal pattern 2
b and the signal pattern 3a on the inner circumferential side of the other radial signal pattern 3 are positioned adjacent to each other in the circumferential direction. Further, the signal patterns 2a to 4a on the inner circumferential side and the signal patterns 2b to 4b on the outer circumferential side are set to have circumferential pattern widths Wa and Wb different from each other (Wa<Wb), and each offset portion g1 to g3 , G1 to G3 are set to the same offset amount.

On the other hand, on the reference track center line 5 of the track A of the alignment disk 1, there is an index burst signal pattern I0 for determining, for example, the reference angular position or reference level of disk rotation.
A burst signal pattern AZ0 for azimuth measurement, which is adjacent to the index burst signal pattern I0 in the head scanning direction and is used to inspect and adjust the azimuth angle of the magnetic head MH, and both sides in the circumferential direction of each signal pattern 2a to 4a, 2b to 4b. Sector signals S1 to S12 for azimuth signal confirmation are provided in parallel with the sector signals S1 to S12.

The alignment disk 1 configured as described above is mounted on a magnetic head M of a disk drive device (not shown).
FIG. 2 shows the waveform of the output signal when reproduced by H. In the figure, the levels LA to LC of the reproduced output signals of the inner signal patterns 2a to 4a and the levels La to Lc of the reproduced output signals of the outer signal patterns 2b to 4b change in the same polarity direction. Become. In this case, three sets of information (level LA, La and level LB,
Lb and levels LC, Lc) can be obtained. Here, the level of the pattern reproduction output signal on each side is determined by the magnetic head M.
When H tracks normally, they are equal to each other (LA
=LB=LC, La=Lb=Lc), but it is different when the magnetic head MH is shifted in the radial direction (LA≠
LB≠LC, La≠Lb≠Lc) appears. The reproduced output signal of the index burst signal pattern I0 is at level I1, and the reproduced output signals of the azimuth measurement burst signal pattern AZ0 are at levels A1 to A4, respectively.

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 signal pattern 2 on the inner circumference side is used.
Levels LA to LC of a to 4a and signal pattern 2 on the outer circumference side
Since it is sufficient to compare the levels La to Lc of b to 4b, there is no need to detect the peak position when automating inspection and adjustment.

Furthermore, in this embodiment, the index burst signal pattern I0, the azimuth measurement burst signal pattern AZ0, and the signal patterns 2a to 4a, 2b to 4b are provided on the same track A. can be simplified.

Furthermore, in this embodiment, the eccentricity of the head tracking trajectory can be detected by comparing the levels LA to LC of the inner signal patterns 2a to 4a and the levels La to Lc of the outer signal patterns 2b to 4b. It is also possible to obtain a disc that is compatible with a disc on which conventional eccentric track patterns 26 and 27 are recorded.

Furthermore, in this embodiment, the signal patterns are provided on the same track A at intervals from each other in the circumferential direction, so that the area occupied by these radial signal patterns 2 to 4 with respect to the disk area does not become large. It becomes unnecessary to detect signals all around the track.

In addition, in this embodiment, the fact that a plurality of pieces of information can be obtained over the entire circumference of the track as the eccentricity detection information of the tracking locus allows measurement errors to be averaged and reduced.

In this embodiment, the case is shown in which the index burst signal pattern I0 and the azimuth measurement burst signal pattern AZ0 are recorded on the alignment disk 1 at one place on the disk surface, but the present invention is not limited to this, and as shown in FIG.
and burst signal patterns AZ0 to A for azimuth measurement
By recording and forming Z5, the accuracy of azimuth measurement can be improved. Here, I0 functions as a time axis detection signal with the mechanical index, and I1 to I5 function as azimuth measurement start signals.

FIG. 4 shows the waveform of an output signal when such an alignment disk 1 is reproduced by a magnetic head MH of a disk drive (not shown). Here, the waveforms I0 to I5, AZ0 to AZ5 and 2 in the same figure
a to 4a, 2b to 4b are the index burst signal patterns I0 to I5, the azimuth measurement burst signal patterns AZ0 to AZ5, the inner signal patterns 2a to 4a, and the outer signal patterns 2b to 4b in FIG. shall correspond.

Further, the number of each signal pattern on the reference track center line 5 in the present invention is not limited to the above-mentioned embodiments, and can be appropriately set as necessary.

Furthermore, it goes without saying that the size of each signal pattern in the present invention is not particularly limited.

[0029]

As explained above, according to the present invention, the index burst signal pattern and the burst signal pattern for azimuth measurement are provided on the same track centered on the disk rotation center, and are arranged in parallel at equal intervals in the circumferential direction. A plurality of sets of radial signal patterns are provided, and each set of radial signal patterns is formed by two signal patterns on the inner and outer circumferential sides parallel to each other with an interval of 180° in the circumferential direction, and each set is formed by two sets of radial signal patterns adjacent to each other. Of the radial signal patterns, the signal pattern on the inner circumferential side of one radial signal pattern and the signal pattern on the outer circumferential side of the other radial signal pattern are positioned adjacent to each other in the circumferential direction, and Since the signal pattern on the outer circumferential side and the signal pattern on the inner circumferential side of the other radial signal pattern are positioned adjacent to each other in the circumferential direction, the reproduction output of the two signal patterns on the inner and outer circumferential sides of each set of radial signal patterns The signal level changes in the direction of the same polarity.

Therefore, when detecting the eccentricity of the magnetic head tracking locus, it is sufficient to compare the levels of the reproduced output signals of each set of radial signal patterns, so there is no need to detect the peak position when automating inspection and adjustment. , signal processing can be simplified.

Furthermore, since a plurality of pieces of information can be obtained over the entire circumference of the track as the eccentricity detection information of the tracking locus, measurement errors can be averaged and reduced, and the accuracy of eccentricity detection can be improved.

[0032] Furthermore, the index and
The provision of a burst signal pattern, a burst signal pattern for azimuth measurement, and a signal pattern on the inner and outer circumference sides,
Since signal pattern recording formation can be simplified, manufacturing costs can be reduced and a dedicated pattern recording/writing machine is not required when pattern recording is formed.

Furthermore, the ability to detect the eccentricity of the head tracking locus by comparing the level of the signal pattern on the inner circumference side and the level of the signal pattern on the outer circumference side makes it possible to detect the eccentricity of the head tracking trajectory by comparing the level of the signal pattern on the inner circumference side and the level of the signal pattern on the outer circumference side. Because you can get discs that are compatible with
Current manufacturing adjustment and inspection equipment can be used during adjustment.

In addition, providing the signal patterns on the same track at intervals from each other in the circumferential direction is ideal for discs with high recording density, since the area occupied by these radial 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 the drawing]

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 of FIG. 1;

FIG. 3 is a plan view schematically showing an alignment disk in another embodiment.

FIG. 4 is a waveform diagram showing a reproduced output waveform obtained by reproducing the alignment disk of FIG. 3;

FIG. 5 is a plan view showing a conventional alignment disk.

FIG. 6 is a waveform diagram showing a reproduced output waveform obtained by reproducing the alignment disk of FIG. 5;

[Explanation of symbols]

1... Alignment disk, 2-4... Radial signal pattern, 2a-4a... Inner circumference side signal pattern, 2b-4
b...Signal pattern on the outer circumference side, 5...Reference track center line,
A... Track, g1-g3, G1-G3... Offset portion, h1-h3, H1-H3... Pattern center line, Q0... Disc rotation center.

Claims (1)

[Claims] Claim 1: An index burst signal pattern and an azimuth signal pattern are provided on the same track centered on the disk rotation center, and a plurality of sets of radial signal patterns are provided in parallel at equal intervals in the circumferential direction, and each of these sets is provided with an index burst signal pattern and an azimuth signal pattern. The radial signal pattern is divided into an inner signal pattern that has an offset part on the outer circumference side of the reference track center line, and a signal pattern on the inner circumference side that is 180 degrees in the circumferential direction.
and an outer signal pattern arranged at intervals of , and having an offset portion on the inner side of the reference track center line; The signal pattern on the outer periphery of one radial signal pattern and the signal pattern on the outer periphery of the other radial signal pattern are positioned adjacent to each other in the circumferential direction, and the signal pattern on the outer periphery of one radial signal pattern and the signal pattern on the inner periphery of the other radial signal pattern The signal pattern of the alignment disk is characterized in that the signal pattern is positioned at areas adjacent to each other in the circumferential direction.