JPS6221084A - Method for setting inspection condition of magnetic disc inspection apparatus - Google Patents

Abstract

PURPOSE:To make it possible to inspect the floating characteristics of both terminal parts, only by moving a float head between the innermost diameter part and the outermost diameter part so that the position and mount angle for setting the float head onto a magnetic disc are determined by setting two parameters to a specific condition. CONSTITUTION:An inspection apparatus has a motor for rotating a magnetic disc 1, a feed screw 3 and a motor 4 for moving a float head 7 to the diameter direction of the disc 1 to locate the same and a means for measuring characteristics at an indexed position. In order to determine the position for setting the head 7 on the disc 1, the offset quantity X1 looked from the parallel line drawn from the center of rotation of the disc 1 in parallel to the moving direction of the feed screw 3 is set as a parameter and, in order to determine the mount angle of the head 7, the crossing angle alpha1 with the moving direction of the disc 1 on said parallel line is set as a parameter. The offset quantity X1 and the crossing angle alpha1 are set so as to simultaneously satisfy the swinging angles alphain, alphaout at the innermost diameter position and the outermost diameter position preliminarily imparted as an inspection condition.

Description

[Detailed Description of the Invention] General Summary The characteristics of flying the head of a magnetic disk vary depending on the circumferential speed, the shape of the head, and the pressurizing conditions, as well as the intersection angle between the axial direction of the head and the direction of movement of the surface of the magnetic disk. (commonly known as yaw angle).

On the other hand, in magnetic disk drives, there are two types of head access (track selection): one in which the head moves straight in the radial direction, and the other in which the head oscillates around a fulcrum.The latter inevitably causes a yaw angle when recording. Since it is maximum at the outermost and outer diameter parts of the track, it is necessary to inspect (confirm) the flying characteristics taking into account the influence of the yaw angle at least at the outermost and outer diameter parts.

The present invention discloses a setting method that simultaneously satisfies the setting of the yaw angle at the outermost diameter portion as this inspection condition.

<Industrial Application Field> The present invention relates to a method for inspecting characteristics in the manufacturing process of magnetic disks, and is particularly applicable to inspection equipment for testing the flying characteristics and read/write characteristics of a single disk, in which characteristics are inspected while the head is flying. Concerning how to set test conditions for this purpose.

<Prior art and its problems> In the conventional test equipment, the track access method of the magnetic disk device was mostly a straight forward method, so basically there was no yaw angle, and the test equipment also had no yaw angle. A linear mechanism was used to move the.

However, in recent years, a method in which track access is performed by swinging the arm around its fulcrum has come into widespread use, and although this method inevitably produces a yaw angle, the flying characteristics and read/write characteristics are affected by the yaw angle. Since this is known, it has become necessary to perform inspections taking the yaw angle into consideration, but since general-purpose inspection equipment uses a straight-line movement system, it is necessary to perform inspections by taking the yaw angle into account. If you try to measure the characteristics by changing the mounting angle, you will have to change the set angle each time, which poses a problem in terms of setup. Also, although it would be better to make a dedicated inspection machine, the cost of making an inspection device is not prohibitive, so if possible, I would like to make the inspection device as versatile as possible.

In this application, in view of the above, the characteristics that need to be recognized for inspection are the characteristics at the innermost position where the yaw angle is maximum and at the outermost position in the case of a swing type. , and the other is by focusing on the fact that preserving the size of the yaw angle will not affect the characteristics so much in the positive and negative directions of the yaw angle, and by setting the conditions in advance by combining the two parameters.
The purpose is to make it possible to inspect the flying characteristics of both ends simply by moving the flying head between the innermost diameter part and the outermost diameter part. In order to achieve this, the inspection equipment must have a means to rotate the disk, a linear movement means that can move and position the flying head in the radial direction of the magnetic disk, and a means to measure the characteristics at the determined position. To determine the position and installation angle of the flying head on the magnetic disk, it is assumed that the set position is parallel to the moving direction of the linear moving means, and the offset seen from a parallel line drawn from the rotation center of the magnetic disk. The amount X is taken as a parameter, and the installation angle is given in advance as an inspection condition using the intersecting angle α with the moving direction of the magnetic disk on the above line (here, the moving direction of the magnetic disk - is perpendicular to this line) as a parameter. Yaw angle αin at the innermost position
Then, X, = Oαl = αin or α01 mouth, and CX 1 n > (X Ou L, then X, = ±X
.

αout=αo +:X1/Rout, αin
=α0 ±
is an algebraic quantity and takes positive and negative values depending on the direction. ), but by setting the above values and moving the flying head, inspection of the innermost and outermost diameter parts can be carried out without changing the setup.

<Example> Figure 1 is an explanatory diagram of an example, which also serves as a principle diagram of the present invention.
3 and 3 are supplementary explanatory diagrams for FIG. 1. As is clear from the diagram in FIG. The spindle and motor (both not shown), the moving table 2 whose degrees of freedom are restricted except for the degree of freedom to move in the direction of a straight line extending radially from the center of rotation 0°, and the moving table moved along the above straight line. a feed screw 3 for positioning by moving in the direction;
A feed motor 4 that drives the feed screw 3 and the moving table 2
A tilting block 5 is prepared such that the tilting can be adjusted in the direction of rotation around an axis parallel to the axial direction of the spindle around a predetermined position P above, and a head arm 6 attached to the tilting 5.
and the head 7 attached to the tip of the navel arm 6 are related elements. Further, 8 is a means for monitoring the flying height.

In the relationship between the above-mentioned related elements, if the straight line on Ot' drawn from the spindle center OI to the axis of the feed screw 3 when viewed from the direction perpendicular to the spindle axis direction is taken as the base line of shaft extension, then this base line 0. o, 'from Ot Ot'
The moving direction in the linear direction is the Y-direction distance y, the plane direction perpendicular to this is the X-direction distance is X, and the tilt (mounting 4) angle of the head 7 attached to the tilt block 5 with respect to the X direction is α
The offset distance from 10HOt' is x5, and the distance from the rotation center OL of the magnetic disk to the innermost diameter and the outermost diameter of the recording portion is Ri, respectively.

On the other hand, the yaw angle (intersection angle between the moving direction of the disk and the head axis) set as the test condition at the position of the outermost radius Ro of the recording portion mentioned above is αOut, and also at the position of the innermost radius R1. If the set yaw angle is αin, then among the above element quantities, αin and αout.

Ri and Ro are values given in advance for the disk test, and Xl and α1 are set values that can be changed freely during the test, so the disk is determined and set at the innermost and outermost diameter positions to be tested. When the tilt angle is given. In order to satisfy αout and αin at the Ro and Ri positions by simply moving the movable table in the Y direction, the following simultaneous equations may be solved.

Sunahara, to be more precise from the diagram, -1χ1 α1n=szn 17±α+ ``-'-(21 Most set yaw angles αout and αin are actually that thick (or 1αout±α11 or 1αin Shimachi
1 is much smaller, so there is almost no problem in practice even if the following approximate value is used instead. 2i Then, the values of xl and α1 obtained from the above simultaneous equations, that is, X+ = (αout-αin) / (1-Ri/Ro) ---1-14) Corresponding to the above, the shaft fulcrum P and the inclination angle are By moving the tilt block 5 and setting xl and α1, all that is left to do is to move the moving table to set αout and R at the respective positions Ro.
Since αin is cented at point 1, testing of the flying characteristics near the positions of Ro and Ri, which have strict judgment conditions, can be done by monitoring the output corresponding to the flying height detected by the monitoring means 8 while moving the head. Can be executed with set conditions.

Figure 2 shows the correspondence between the change in tilt angle (yaw angle) when using an actual swinging access arm and the change in tilt angle when using this method. The absolute value is the same at the Ro or R4 position, but the direction of the slope is different from the actual one in either case, and Ri and Ro
It can be seen that the inspection conditions become more severe in the middle part because the middle part does not match the actual case.

This situation is shown in Figure 3. If the average value of the head flying height is set under the conditions for a tilt angle of 0 and the yaw angle is taken under the same conditions, the output of the monitoring means 8 tends to increase, and the flying height decreases, causing contact. You can see that it becomes easier.

Effect> As explained above, according to the present invention, when testing the flying characteristics of a magnetic disk, it is possible to test the flying characteristics at the innermost and outermost portions of the recording surface in conjunction with the yaw angle set in the actual device. This can be done using a general-purpose testing machine with a straight-line moving means, and if the parameters You can test without changing cents by simply selecting the same head position as in the case.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of an embodiment that also serves as a principle diagram of the present invention, and Figures 2 and 3 are supplementary diagrams of Figure 1, each explaining the correspondence of yaw angles and the monitoring output associated with yaw angles. This explains how to deal with this. In the figure, 1 is a magnetic disk, 2 is a moving table, 3 is a feed screw, 4
is the feed motor, 5 is the tilt block, 6 is the heel arm,
7 is the head, 8 is the monitoring means, 01 is the rotation axis,
The line OHO+' is the base line +xl is the offset amount, α
1 is the tilt setting angle of the head 7, αout. Figure 2 Amount of displacement (3-angle θ) Figure 3

Claims (1)

[Scope of Claims] A magnetic disk inspection apparatus comprising means for rotating a magnetic disk as an object to be inspected, and linear movement means for moving a measuring floating head in the radial direction of the magnetic disk, comprising: The mounting angle α_1 with respect to the moving direction of the linearly moving means and the position of a straight line drawn upward in parallel to the moving direction of the linearly moving means following the center of rotation of the means for rotating the magnetic disk at the mounting position of the floating head. Using the offset amount X_1 as a setting parameter, simultaneously set the tilt angle at the innermost and outermost radial positions with respect to the moving direction of the magnetic disk surface of the flying head, which is specified as an inspection condition at the innermost and outermost recording positions of the magnetic disk. A method of setting inspection conditions for a magnetic disk inspection device, characterized by realizing the same.