JPS60239914A - Alignment disc - Google Patents

Abstract

PURPOSE:To write alignment signals theoretically with a high precision by inverting and writing alignment signals of an upper face and a lower face by a signal writing device having a single write head and giving prescribed positional relations to write start points of alignment signals. CONSTITUTION:A hub receiving part 31 which catches a hub 20 of an alignment disc 10 has a shaft 30, and the hub 20 can be inverted and set to the receiving part 31. A length measuring machine 40 is used to measure optically the length from the center of the shaft 30 to a signal write head 50, and the write diameter can be measured by another length measuring machine 41 in the state where the disc 10 is set. Write centers (A and B) of the upper face and the lower face of the disc 10 and write start points of alignment signals are arranged on one line approximately to minimize the alignment error due to eccentricity of centers A and B. In a writing device 60, the write precision is improved because disc touch is stabilized unlike a gimbals supported head.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an alignment disk for the purpose of adjusting a double-sided magnetic head magnetic disk drive device, and particularly relates to an alignment disk for the purpose of adjusting a double-sided magnetic head magnetic disk drive device. rack pe
This relates to an alignment disk used in the 48TpI class or above, which requires high accuracy in writing alignment signals.3 [Background of the Invention] Conventional alignment disks are of the 529 μm pitch level for the 48TpI class. Although the alignment signal did not require much precision, the azimuth detection signal that checks the angular error (hereinafter referred to as azimuth error) between the R/W (read/write) gap of the head and the specified direction was , an accuracy of ±2' is required, and when the alignment signal writing head is assembled from top to bottom, the two R and /W gaps are hidden from each other, making it impossible to directly verify the accuracy. There were problems in terms of warranty and maintenance.

Furthermore, since it is difficult to guarantee the accuracy of the azimuth detection signal itself, there is a problem in guaranteeing the accuracy of the adjusted and verified drive, and there has been little hope for improved accuracy.

Furthermore, at a pitch level of 2548 m or higher for the 100 Tpi class, the accuracy of the track diameter must be at least ±4 μm level, and the accuracy of the index timing angle must be at least ±5.4 lbel, so from the perspective of maintaining and guaranteeing signal accuracy, For example, in a writing method using a button head on one side and a gimbal-supported head on the other side, there is a problem in the reproducibility of the head position due to the rigidity of the gimbal, and as a result, the required accuracy cannot be satisfied. This problem arises due to the structural necessity of having a gimbal support structure for one head in order to make stable contact between the button head on one side and the head on the other side with the media without any spacing loss. This affects the reproducibility of the index timing and the stability of the index timing angle accuracy, and it is difficult to satisfy the accuracy required for the alignment disk in the case of ]00'J'' pi class or higher.

[Purpose of the invention]

The present invention utilizes, as an alignment signal writing device, a signal writing device having a single writing head, in which the signal writing accuracy is structurally stable because of the fixed support head that generally uses a button head or the like. The object of the present invention is to provide an alignment disk on which alignment signals can be theoretically written with high accuracy on an alignment disk for a double-sided head.

[Summary of the invention]

The configuration of the alignment disk according to the present invention is such that at least one disk has an alignment signal for use in adjusting a magnetic disk drive device having a magnetic head on each of the upper and lower surfaces. An alignment signal on each of the upper and lower surfaces of the alignment disk is inverted and written by a signal writing device having a single writing head, and an inverted alignment signal is written on each of the upper and lower surfaces of the alignment disk. Writing is performed such that the eccentric direction connecting the centers and the writing start point of the alignment signal have a constant positional relationship.

Additional information is as follows.

When writing alignment signals to an alignment disk for a double-sided magnetic head using a signal writing device with a single write head, after writing signals on the - side, turn the disk over and write it again on the other side. Signal writing is performed, but the writing centers of the alignment signals before and after inversion do not necessarily match, and are generally 10 to 50.
An error of μm occurs in the case of a 3-inch compact floppy disk (hereinafter abbreviated as CFD).

By making the eccentric direction connecting the writing centers of one side and the other side, which have an error of 10 to 50 μm, approximately coincide with the straight line direction connecting the writing start point of the alignment signal and the writing center, the theoretical The azimuth error and index timing error are minimized to ensure the required accuracy.

[Embodiments of the invention]

An embodiment of the alignment disk according to the present invention will be explained by referring to each figure.

FIG. 1 is a schematic plan view of an alignment disk according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of errors due to eccentricity of index timing detection signals, and FIG. 3 is a graph of the analysis results. , FIG. 4 is an explanatory diagram of the error caused by the amount of eccentricity of the azimuth detection signal, FIG. 5 is a graph of the analysis results, FIG. 6 is a plan view of the alignment disk with a hub, and FIG. 7 is its diagram. No. 6 showing the chucking configuration
FIG. 8 is a cross-sectional view taken along the line XX in the figure, and a perspective view showing a schematic configuration of the signal writing device.

Note that FIGS. 1, 2, and 4 are all views of the alignment disk viewed from the bottom, and hereinafter, the negative side refers to the bottom surface, and the other side refers to the top surface.

In FIG. 1, the alignment disk 10 according to the present embodiment has a signal writing device (No. 8 After writing the alignment signal on the - side (described later with reference to the figure), the alignment signal on the other side is written by inverting the alignment disk 10.

However, the above-described cutting center All of the alignment signal on one side does not necessarily coincide with the writing center B12 of the alignment signal on the other side in terms of manufacturing accuracy, and the eccentricity ε210 shown in the figure is 50 m, and 13 is the eccentric direction between these two points, which is indicated by an arrow.

However, in this embodiment, the writing start point 14 of the alignment signal is placed almost on the same straight line as the writing centers All and B12, and has a constant positional relationship.

An error in the alignment signal in the alignment disk 10 formed as described above will be explained.

That is, here, taking a 100Tp 1.3 inch CFD as an example, we will explain the innermost track (Tl'
t39) Index timing detection signal (hereinafter referred to as index timing signal) based on eccentricity ε = 10 to 50 μm at Nidrak diameter R39 = 22.594
15. Azimuth detection signal (hereinafter referred to as azimuth signal).

)16 error will be explained.

To explain the error caused by the eccentricity ε in the index timing signal 15 in FIG. 2, the index hole 18 which detects the index timing and is located r=14.5 m away from the center, the writing center All, B12, and the index timing signal 15 If the angles formed by the writing starting point 14, etc. are respectively θA, θB, etc. shown in the figure, then the error when the eccentric direction of ε is the angle α made with the writing starting point 14 as shown in the same figure is as follows. become.

θB−π−(θB1+θB2) Also, since θ mu π can be set, as a result, (9) It is expressed as follows.

θA−θB=(θB1+θB2) Therefore, FIG. 3 shows the calculation results for the case where ε=10 to 50 μm as described above.

From this result, it can be seen that when ε=50 μm, α is set to 15°, and when ε=30 μm, α is set to 27° to satisfy the target accuracy of ±5.4′.

Here, the method of achieving the above-mentioned fixed positional relationship is, for example, as follows.

That is, by using a hub whose shape determines the writing center of each of the upper and lower surfaces, which will be described later, precisely matches, the upper and lower surfaces can be reversed to enable writing by the signal writing device (10). The above index hole 18 and the index hole 1 (not shown)
A light emitting part and a light receiving part provided under the alignment disk 10, which detects the position of the hole 8, form a writing start point signal detection part that defines the writing start point of the alignment signal. It is something.

Furthermore, a magnetic detection method can be employed for the above detection.

Next, as shown in FIG. 4, when the error caused in the azimuth signal 16 due to the eccentricity ε is included, the following results are obtained.

As shown in FIG. 4, the angular error γ in the azimuth signal 16 is determined by the index hole 18 . It is determined as the intersection angle γ between a straight line connecting the writing center B12 and the writing start point (on the other side) 19, and a straight line connecting the writing center A11 related to the point at the time of reading and the writing start point 19.

trench, distance between points 12 and 18"" L x-, points 19 and 1
1 distance -1z-, and φ2 as shown in the figure (11
) Ax = J E 2+ r2+26 rcO3αAx
r sinα sinφ2 tz ε sinφ2 sinγ.

Therefore, the angular error can be calculated as follows.

r=sin-' (sinφ2) z=sin"" (sinα) zlx Therefore, FIG. 5 shows the calculation results for the case where ε=10 to 50 μm.

(12) From this result, it can be seen that if ε=50 μm, α≦15°, and 6230 μm, α≦26°, the target accuracy ±2.0′ is satisfied.

Next, the hub of the alignment disk that defines the amount of eccentricity ε will be explained using FIGS. 6 and 7.

The plastic hub 20 provided at the center of the alignment disk 10 can be inserted into the shaft 30 of the attachment part with the upper and lower sides reversed, and the head of the shaft 30 and the right-angled surfaces 21 and 22 of the hub 20 , the writing and reading centers during chucking are positioned.

Therefore, when manufacturing a mold for injection molding the hub 20, the eccentricity of the upper and lower surfaces can be precisely matched to some extent, but an error on the mold of about 10 to 30 μm may occur during mold manufacturing. In the present invention, even if the eccentricity ε=10 to 50 μm, the angle α between the eccentric direction 13 and the writing start point 14 is specified at the time of manufacturing the alignment disk (13). As stated above, this allows sufficient manufacturing without compromising the required accuracy as an alignment disk.

Here, the outline of the signal writing device 60 described above will be explained in the eighth section.
This will be explained with a diagram.

That is, the hub receiver part 31 for chucking the knob 20 of the alignment disk 10 has a shaft 30, and can be inserted with the hub 20 turned upside down or down.

Using a length measuring device 40, the distance between the center of the shaft 30 and the signal writing head 50 can be optically measured, and for the writing diameter, another length measuring device 41 is used to measure the alignment disk 10. The signal writing device 60 has a configuration that allows measurement in the inserted state, and has reproducibility.

Note that M is an optical instrument such as a microscope.

However, the alignment signal of the alignment disk 10 is generated by a signal writing device 60 having a single signal writing head 50 composed of a fixed support head such as a button head.
Since the track diameter detection signal (
Hereinafter, this will be referred to as the track diameter signal. ) 17, the index timing signal 15 and the azimuth signal 16 were also stabilized, and the accuracy was improved.

Furthermore, since an alignment disk for a double-sided head can be created using the signal writing device 60 having a single writing head, the accuracy of the writing head 50 can be directly optically checked as described above, and therefore the signal writing device 60 can be directly checked for accuracy as described above. It is possible to easily maintain high accuracy.

According to this embodiment, alignment signals for a double-sided head can be written in reverse using a single write head, and therefore the optical accuracy of the write head can be verified. Since the fixed support head can also be used, it is possible to eliminate variations in alignment signals that occur when using a jimpal support head.

In addition, by arranging the writing centers A and B and the writing start point of the alignment signal (15) on the same straight line, the error in the alignment signal due to the eccentricity ε that occurs between the writing centers A and B can be minimized. It is something that can be transformed into

Thus, the knob of the above embodiment may be made of metal.

In the embodiment, an index timing signal 15. is also used as an alignment signal. An azimuth signal 16 and a track diameter signal 17 are provided.
This does not preclude the provision of at least one of them.

Additionally, a hub can be used.

That is, if the collet part of the signal writing device is used as the mounting portion for the alignment disk, for example, the aforementioned noise can be avoided.

In the example, the eccentric direction and the writing start point are
Assuming that there is a certain positional relationship on the straight line, this is
For example, the writing start point (16) of the azimuth signal may be placed in a fixed positional relationship in a direction perpendicular to the eccentric direction.

〔Effect of the invention〕

According to the present invention, as an alignment signal writing device, a writing device having a single writing head whose signal writing accuracy is structurally stable due to a fixed support head generally using a button head or the like is used, It is possible to provide an alignment disk in which alignment signals can be theoretically written with high accuracy on an alignment disk for a double-sided head, and it can be said that this invention has excellent practical effects.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of an alignment disk according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of errors due to eccentricity of index timing signals, and FIG. 3 is a graph of the analysis results. Figure 4 is an explanatory diagram of the error due to eccentricity of the azimuth signal, Figure 5 is a graph of the analysis results, Figure 6 is a plan view of the alignment disk with a nop, and Figure 7 [17] 6 is a cross-sectional view taken along the line X--X in FIG. 6, showing the chucking structure, and FIG. 8 is a schematic perspective view of the signal writing device. 10... Alignment disk, 11... Writing center A112... Writing center B113... Eccentric direction, 14... Writing start point, 15... Index timing detection signal, 16... Azimuth detection signal , 17
... Track diameter detection signal, 18 ... Index hole, 19 ... Writing start point, 20 ... Knob, 21
．． 22... Right angle surface, 30... Shaft, 31...
Knob holder is part, 40° 41... Length measuring device, 50... Writing head, 60... Signal writing device. Agent Patent attorney Kosaku Fukuda (and 1 other person) (18) Nagisa 2 (l ¥11 High school 3rd figure Tomaribe (°) Mo5 figure Angle 0

Claims (1)

[Claims] 1. An alignment disk for a double-sided magnetic head, which has alignment signals for at least one disk used to adjust a magnetic disk drive device having a magnetic head on each of the upper and lower surfaces. , the alignment signals on the upper and lower surfaces of the upper and lower surfaces are inverted and written by a signal writing device having a single writing head, and the alignment signals on the upper and lower surfaces are inverted and written. An alignment disk characterized in that writing is performed such that an eccentric direction connecting the centers and a writing start point of the alignment signal have a constant positional relationship. 2. In the item described in claim 1, the writing start point of the alignment signal and the two writing centers on the upper surface and the lower surface are arranged on a straight line as a fixed positional relationship. alignment disc. 3. The alignment disk according to claim 1, which has at least one of an azimuth detection signal, an index timing detection signal, and a track diameter detection signal as an alignment signal. 4. In either of claims 1 or 2, in the center of the alignment disk,
A positioning hub is provided to determine the writing center of the upper and lower surfaces, and the shape of each of the upper and lower surfaces is precisely matched and comes into contact with the mounting section. and a writing start point signal detection unit that defines the writing start point of the alignment signal. An alignment disc on which writing is done so that the two writing centers on the bottom side have a certain positional relationship.