JPH07105041B2 - Glide tester of magnetic disk - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a glide tester for a magnetic disk, which removes protrusions existing on the surface of the magnetic disk and inspects the results.

[Prior Art] A magnetic disk used as a storage device of a computer system is becoming higher in density due to miniaturization of a magnetic medium and improvement of performance. This requires that the surface be extremely smooth. In the manufacture of magnetic disks, after coating a magnetic medium film, it is ground (grinded) to make it smooth, but even if it is polished, there are protrusions that hinder the smoothness (glide) to some extent. The protrusion is removed by a process called. In addition to the burnishing process, the presence or absence of protrusions is inspected. In this case, a large amount of fine particles of polishing dust are generated in the polishing process, so avoid invading it into the inspection device and its surroundings, and burnish and inspection are separate processes from polishing, and the glide tester is used collectively. Is done by.

Here, a method of burnishing and inspecting the protrusions in the glide tester will be described.

FIG. 5 illustrates the floating operation of the write / read magnetic head in the magnetic disk device. When the magnetic disk 1 rotates in the direction of arrow θ, an air flow indicated by arrow A is generated on the surface. On the other hand, since the slider 2a holding the magnetic head 2 is inclined as shown in the figure, the slider 2a floats, and the magnetic head 2 acts between the magnetic medium and the surface thereof in a non-contact state. The slider 2a is urged downward by a spring 4 with an appropriate force. Also, the flying height Δ
h is as small as 0.2 μm. In the glide tester, it is necessary to perform a protrusion inspection with the same flying characteristics as this magnetic head. For this purpose, the same slider 3a as the slider 2a shown in FIG. 5 is used, and instead of the magnetic head 2, The protrusion detection head 3 is formed by attaching the protrusion sensor 3b using a piezo element. The protrusion sensor 3b generates an electromotive force by the impact force at the time of collision with the protrusion 5 to detect the presence of the protrusion.

FIG. 6 is an explanatory view of the burnish head 6 of the glide tester. Like the magnetic head described above, a slider system that floats by the air flow A is used, but the slider is made of a harder material than that of the magnetic head. , A sharp cutting edge 6a in the oblique direction is carved on the surface side of the magnetic disk 1, and when the projection 5 collides with this, it is scraped off,
It will be burnished. The pressing force of the spring 4 is also made larger than that of the magnetic head.

FIG. 7 is a block diagram of a conventionally used glide tester, in which the projection detecting head 3 and the burnishing head 6 are attached to carriages 7 and 8 which move in the directions R ₁ and R ₂ of the radius of the magnetic disk 1, respectively. ing. Motor 7a
The moving portion 7b of the carriage 7 is moved by this, the burnishing work of the projection 5 is performed by the burnishing head 6 at the tip thereof, and the moving portion 8b of the carriage 8 is moved by the motor 8a.
Is moved, and the result of burnishing of the protrusion 5 is inspected by the protrusion detection head 3.

By the way, since various protrusions having different sizes and shapes are present on the surface of the magnetic disk 1, the actual burnish and its inspection work are not simple but rather rather complicated. That is, the protrusion inspection is first performed, the position of the protrusion is stored in the memory, the burnish is performed several times at this position, and then the inspection is performed, and when the result is not sufficient, the burnish is repeated. When the protrusion is large, the varnish and the inspection are alternately repeated several times. In addition, there is know-how to use the glide tester, such as how to take the rotation speed in the burnish, adjustment of the pressing force, or the moving direction and speed of the burnish head are important, and in any case, it is troublesome. It is work. In this case, switching between the burnishing and the inspection requires time for exchanging the burnishing head and the protrusion detecting head, which causes a problem that the required time, that is, the tact time becomes long.

On the other hand, it is considered that a protrusion detection sensor is attached to the burnish head to carry out the burnishing and the inspection work centrally and simultaneously, but the burnishing head is similar to the magnetic head of a practical magnetic disk device in shape and weight. Since the load and the levitation characteristics are different, it is impossible to accurately inspect the protrusion.

On the other hand, it is desirable to have an effective glide tester capable of shortening the tact time by reducing the number of times the burnish and inspection are alternately switched as much as possible.

[Object of the Invention] In view of the above circumstances, the present invention can reduce the number of times of switching between burnish and projection inspection work, which is a drawback of the conventional glide tester. The purpose is to provide a glide tester.

[Means for Solving Problems] The present invention is directed to a burnish head that floats by an air flow generated on the surface of a rotating magnetic disk and collides with a projection existing on the surface to remove the projection, and a projection on the burnish head. With a first protrusion sensor for detecting the approximate value of the size of the protrusion, and a protrusion protrusion having a second protrusion sensor for detecting the protrusion remaining on the surface with high accuracy after the protrusion removal work by the burnish head. It is a glide tester for magnetic disks consisting of a head.

As an embodiment, two sets of carriages that are orthogonal to or opposite to each other in the center of rotation of the magnetic disk and are movable in the radial direction of the magnetic disk are provided, and one carriage is opposed to the upper surface and the lower surface of the magnetic disk, respectively. Provided are two burnishing heads having a first protrusion sensor, and at the other one are provided two protrusion detection heads having a second protrusion sensor facing the above-mentioned upper surface and lower surface. It is a thing.

As another embodiment, in the peripheral portion of the magnetic disk,
A Y-axis carriage that moves in the radial direction of the magnetic disk is provided, and an X-axis carriage that moves in the direction perpendicular to the radius is attached to the moving portion of the Y-axis carriage.
Two burnish heads each having a first protrusion sensor facing the upper surface and the lower surface of the magnetic disk, and two burnish heads having a second protrusion sensor respectively facing the upper surface and the lower surface. The projection detecting heads are arranged at regular intervals.

[Operation] In the glide tester for a magnetic disk according to the present invention, the burnishing head burns the projection on the surface of the magnetic disk, and the first projection sensor detects an approximate value of the size of the projection. However, since the operating characteristics such as the flying of the burnish head are considerably dull as compared with the magnetic head of the magnetic disk device, the obtained detection data is limited to the approximate size of the protrusion. However, due to repeated burnishing,
Since the first protrusion sensor can observe the situation where the protrusions are gradually scraped off, the burnishing work can be performed smoothly. After sufficient burnishing work is performed in combination with such a protrusion inspection, the protrusion detection head is switched to the second
The glide test is completed by performing a highly accurate final inspection with the projection sensor of. As a result, the number of times the heads are switched is reduced as compared with the conventional glide tester, and the takt time is greatly shortened.

[Embodiment] FIG. 1 is a view showing an embodiment of the structure of a burnish head 6 having a first protrusion sensor 3b 'in a glide tester for a magnetic disk according to the present invention, and a slider similar to the conventional one described above. The first protrusion sensor 3b 'of the piezo element is embedded and fixed in the groove 6b of 6a. Burnish head 6
Has the same burnishing action as that of the conventional one, but the operating characteristics such as levitation are slower than those of the magnetic head, so the detection sensitivity of the first detection sensor 3b 'is low, and the approximate size of the protrusion is I can only know.

2 (a) and 2 (b) are plan views showing the structure of an embodiment of a glide tester for a magnetic disk according to the present invention. In FIG. 1A, carriages 7 and 8 for moving the burnishing head 6 and the projection detecting head 3 in two directions R ₁ and R ₂ orthogonal to the rotation center 0 are provided for the magnetic disk 1. The above-mentioned first detection sensor 3b 'is attached to the burnish head 6. The protrusion detection sensor 3 is similar to the conventional one described above, and the second detection sensor 3b is attached to the slider 3a. FIG. 1B shows the X and Y axes which are orthogonal to each other in the peripheral portion of the magnetic disk 1, and the Y axis is the magnetic disk 1.
The carriage 9 that moves in this direction is provided as the direction of the radius R, and the carriage 10 that moves in the X-axis direction is attached to the moving portion (not shown). The burnish head 6 and the projection detection head 3 are arranged at regular intervals by using a support rod 10b on a moving portion (not shown) of the carriage 10.
Although the arrangement of the carriage is different between FIGS. (A) and (b), the burnishing head 6 and the projection detecting head 3 of both of them perform the same operation by arbitrarily moving on the surface of the magnetic disk 1. .

FIG. 3 is a view showing a side surface with respect to FIG. 2 (a), in which a spindle 12 is provided at the center of the base board 11 and the magnetic disk 1 is mounted thereon. On the carriages 7 and 8 arranged on the base board 11 in the peripheral portion of the magnetic disk 1, two burnish heads 6-1 and 6- are provided so as to face the upper surface and the lower surface of the magnetic disk 1, respectively. 2 and the protrusion detection heads 3-1 and 3-2 are attached.
As a result, the burnishing and inspection work can be performed on both the upper and lower surfaces at the same time. The motors 7a and 8a are for rotating the carriages 7 and 8.

FIG. 4 is a basic configuration diagram of a circuit in an embodiment of a glide tester for a magnetic disk according to the present invention. In the figure, the driver is controlled by the control of the microcomputer 19.
Driving currents are supplied from the motor A and the motor B from the driver A13-1 and the driver B13-2, respectively, and the carriage 7 is driven.
Alternatively, the carriage 8 moves. Similarly, the current from the driver C causes the spindle 12 to rotate.

The two first protrusion sensors 3b'-1, 3b'-2 and the two second protrusion sensors 3b-1, 3b-2 are respectively preamplifiers 14-1, 14-2, 14-3 and The signal is appropriately amplified by 14-4, and the one in operation is selected by the selection circuit 15 according to the instruction of the microcomputer 15 and input to the protrusion detection circuit 18 via the main amplifier 16 and the bandpass filter 17. Here, the bandpass filter 17 is the protrusion sensor 3
This is for cutting unnecessary high-frequency parts such as the natural vibration of the sensor included in the signals detected by b and 3b ', and capturing only the fundamental wave at the moment of collision with the protrusion.

In the protrusion detection circuit 18, the threshold value V _s is set in advance at the terminal 18a,
The detection voltage exceeding this is output as significant and noise is cut. The output signal of the protrusion detection circuit 18 is subjected to predetermined processing by the microcomputer 19. As described above, the burnish and protrusion inspection work by the glide tester is repeated a large number of times for protrusions of various sizes, but in the present invention, the protrusion sensor provided on the burnish head 6 is used. With 3b ', the state where the projection is scraped off can be detected at any time during the burnishing work, and the head switching as in the conventional glide tester is unnecessary. It should be noted that the burnishing and inspecting operations are all performed by the microcomputer 19 based on empirical data, but the above-described mechanism and circuit are sufficiently capable of controlling them.

[Effects of the Invention] As is apparent from the above description, according to the glide tester for a magnetic disk of the present invention, the state in which the protrusions are burnished and gradually disappear during the burnishing operation is switched to the protrusion detection head. Since it is possible to detect and observe any time with the burnish head as it is, it is possible to efficiently burnish protrusions of various sizes and shapes. In addition, the effect that the tact time can be greatly shortened by this is extremely large.

[Brief description of drawings]

FIG. 1 is a structural diagram of a burnish head in which a first protrusion sensor is mounted in a magnetic disk glide tester according to the present invention, and FIGS. 2A and 2B are magnetic disk glide tester according to the present invention. 3 is a plan view showing the structure of the embodiment of FIG. 3, FIG. 3 is a side view with respect to FIG. 2 (a), FIG. 4 is a basic configuration diagram of a circuit with respect to FIG. 3, and FIG.
Fig. 6 is a structural diagram of a magnetic head and protrusion detection head of a glide tester, Fig. 6 is a structural diagram of a burnish head of a conventional glide tester, and Fig. 7 is an arrangement of a burnish head and a protrusion detection head in a conventional glide tester. It is a top view explaining the operation. 1 ... magnetic disk, 2 ... magnetic head, 2a, 3a ... slider, 3b, 3b '... protrusion sensor, 4 ... spring, 4 ...
… Protrusions, 6 …… Burnish head, 6a …… Cutting blade, 6b
...... Groove, 7,8,9,10 …… Carriage, 10b …… Support rod, 11
...... Base board, 12 ...... Spindle, 13 ...... Driver, 14
...... Preamplifier, 15 …… Selection circuit, 16 …… Main amplifier, 17 …… Band pass filter, 18 …… Protrusion detection circuit, 18 a …… Terminal, 19 …… Microcomputer.

Claims (3)

[Claims] 1. A burnish head which floats by an air flow generated on the surface of a rotating magnetic disk and collides with a projection existing on the surface to remove the projection, and the size of the projection on the burnish head. And a projection detection head having a second projection sensor for highly accurately detecting the projections remaining on the surface after the work of removing the projections by the burnish head is attached. A glide tester for magnetic disks, which is characterized by 2. A first projection, wherein two sets of carriages that are movable in the radial direction of the magnetic disk are provided, and one of the two carriages faces the upper surface and the lower surface of the magnetic disk, respectively. Two protrusion detection heads provided with two burnish heads each having a sensor and having the second protrusion sensor, which faces the upper surface and the lower surface of the other carriage of the two sets, respectively. The glide tester for a magnetic disk according to claim 1, further comprising: 3. A Y-axis carriage that moves in the radial direction of the magnetic disk is provided in the peripheral part of the magnetic disk, and an X-axis carriage that moves in the direction perpendicular to the radius is attached to the moving part of the Y-axis carriage. Two burnish heads having the first protrusion sensor, which face the upper surface and the lower surface of the magnetic disk, respectively, and a carriage in the X-axis direction, which face the upper surface and the lower surface, respectively. The glide tester for a magnetic disk according to claim 1, wherein the two protrusion detection heads having the second protrusion sensor are arranged at regular intervals.