JPH0762947B2 - Magnetic disk device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device capable of contributing to realization of high density recording / reproducing.

[Technical background of the invention and its problems]

As is well known, magnetic disk devices are widely used as external storage devices for computers.

The main parts of such a magnetic disk device are generally a magnetic disk plate that is rotationally driven by a rotary drive source, a slider that is movable along the magnetic disk plate, and a magnetic disk that is fixed to the slider. And a magnetic head for writing and reading information to and from the plate. Generally, it is not preferable to directly contact the slider or the magnetic head with the magnetic disk plate rotating at a high speed. Therefore, in the conventional magnetic disk device, the slider has the function of supporting the magnetic head and the compressed air flow between the magnetic disk plate and the disk surface when the magnetic disk plate is rotated while facing the magnetic disk plate. And the slider itself is levitated by this dynamic pressure, thereby exerting the function of preventing the slider and the magnetic head from directly contacting the disk surface. Then, usually, a method is adopted in which the magnetic head is positioned at a point where the lift force generated on the slider and the pressing force by the spring material or the like are balanced.

By the way, recently, the advent of a magnetic disk device having a sufficiently high recording density is desired, and such a demand 1
Use of a perpendicular magnetic recording medium is considered as one means. As described above, when the perpendicular magnetic recording medium is used, in order to maximize the characteristics of this recording medium, the clearance between the magnetic head and the magnetic disk plate is suppressed to 0.1 μm or less, and its fluctuation is extremely small. It is necessary to keep it small.

Usually, the fluctuation of the flying height from the viewpoint of electrical and mechanical characteristics is
It is required to be kept within 10% of the flying height. For example, when the clearance between the magnetic head and the magnetic disk plate is 0.3 μm, the allowable fluctuation amount Δh max is 0.03 μm.
When the clearance is 0.1 μm, Δh max is
It becomes 0.01 μm, and the conditions become more severe.

Conventionally, as means for improving the performance of such a slider, a negative pressure is generated on the slider surface, and this negative pressure is used as a pressing force of the slider against the disk surface. There is a so-called negative pressure slider. However, in order to realize this, it is necessary to strictly control the flying height of the negative pressure slider, and it is necessary to check whether or not the flying height specifications are met by performing a total or partial sampling inspection during product assembly. is there. However, since the flying height itself is on the order of 0.1 μm, interference fringes do not appear even if an attempt is made by a known optical interferometry, and the measurement cannot be performed. For this reason, it is not possible to obtain information on the flying height and flying posture of the negative pressure slider in an actual product, which makes it difficult to realize high-density recording.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object thereof is to provide a negative pressure slider itself with an element that can contribute to accurate measurement of the flying height of the negative pressure slider, and thereby to assemble it. It is another object of the present invention to provide a magnetic disk device capable of performing high-precision control of the flying height at some times and thus achieving high-density recording.

[Summary of the Invention] The present invention provides a magnetic disk that is rotationally driven, and is movably provided along the surface of the magnetic disk, and levitates above the surface of the magnetic disk by dynamic pressure generated as the magnetic disk rotates. A slider on which a sliding surface is formed for
In a magnetic disk device having a magnetic head fixed to the slider and writing and reading information to and from the magnetic disk, the slider is 0.1 to 2 in a direction away from the magnetic disk with respect to the sliding surface.
It is characterized in that it has a negative pressure generating surface formed with a step of μm, and the negative pressure generating surface is configured as a mirror surface.

[Advantages of the Invention] In the magnetic disk device according to the present invention, the slider itself is
The negative pressure surface (negative pressure generation surface), that is, the surface separated by a small step from the sliding surface to the side opposite to the disk surface is a mirror surface. Therefore, assuming that the minute step is 1 μm, the clearance between the disc surface and the mirror surface portion is 1.1 μm when the sliding surface is levitated by 0.1 μm from the disc surface. This clearance amount is a value sufficient to apply the optical interference method. That is, it is a value that can generate interference fringes. Therefore,
It is possible to check the flying height and flying attitude of the sliding surface by optical interference method by combining the slider with a magnetic head built into the product before assembly, the suspension supporting the slider, and the pseudo magnetic disk plate made of transparent material. Becomes In this way, the flying height and flying posture of the slider can be checked and strictly controlled, so that the flying height required for high-density recording can be set, and the life of the recording medium and magnetic head is damaged by friction during CSS. As a result, high density recording can be realized.

Example of Invention

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of an example in which the present invention is applied to a magnetic disk device having only one magnetic disk plate.

That is, reference numeral 1 in the drawing is a magnetic disk plate, and this magnetic disk plate 1 is fixed to the outer periphery of the shaft 2. The shaft 2 is connected to a rotary drive source 3, which is a control device 4
Controlled by. A recording medium layer composed of a perpendicular magnetic recording medium is formed on the upper surface of the magnetic disk plate 1 in the figure. The recording medium layer is used for positioning and data.

A magnetic head 5 is arranged near the upper surface of the magnetic disk plate 1 in the drawing, and the magnetic head 5 is supported by a carriage 9 via a negative pressure slider 6, a suspension mechanism 7 and an access arm 8. The carriage 9 is
The actuator 10 is supported by an actuator 10 controlled by the control device 4, and its movement is selectively controlled in a direction indicated by an arrow 11 in the figure. The control device 4 controls the rotary drive source 3 and the actuator 10 in the same manner as a known one.

The negative pressure slider 6 is of a type that floats by dynamic pressure in relation to the suspension mechanism 7, and specifically, it is a second type.
It is configured as shown in the figure. That is, the sliding surface 13 faces the magnetic disk plate 1 of the slider block 12.
It has a negative pressure surface (negative pressure generating surface) 14 that forms a concave portion with, and this negative pressure surface 14 is a mirror surface. Further, on the fluid inflow end side, there is an inclined surface 15 that gradually separates from the disk surface in the counter-rotational direction with respect to the rotational direction of the magnetic disk plate 1. The minute step (recess depth) S between the sliding surface 13 and the negative pressure surface 14 is set to a certain value in the range of 0.1 to 2 μm, for example, 1 μm.

On the other hand, the magnetic head 5 is fixed so that the magnetic gap G is located at a level flush with the sliding surface at the end surface of the negative pressure slider 6 located on the rotational direction side with respect to the rotational direction of the magnetic disk plate 1. A thin film head 16 is provided.

With such a structure, when the magnetic disk plate 1 rotates, a compressed air flow is formed between the sliding surface formed on the negative pressure slider 6 and the magnetic disk plate 1, and this dynamic pressure causes the negative pressure slider 6 to move. Emerges. At this time, a strong negative pressure is generated on the upstream side of the negative pressure surface 14 in the rotation of the disk. Since this position is in front of the pivot support point of the negative pressure slider 6, the outflow end portion of the negative pressure slider 6 due to the action of the moment. Quickly levitate the magnetic head part of. Further, in the negative pressure slider, since the pressing spring force is set to be small, it has a property that it easily floats at the time of start-up when the amount of pressing force generated by the negative pressure is small. Due to these actions, the negative pressure slider 6 quickly floats as the magnetic disk 1 starts to rotate,
It is possible to minimize damage to the recording medium and the magnetic head due to the contact travel of both. Therefore, the flying height is
For example, the characteristics of the perpendicular magnetic recording medium can be brought out to the maximum and the recording density can be greatly improved by setting the conditions of each part in advance so as to be about 0.1 μm or less.

By the way, in order to maximize the characteristics of the perpendicular magnetic recording medium as described above, before assembling the magnetic disk device, it is confirmed whether or not the slider 6 actually incorporated satisfies a predetermined flying height specification. Although it is necessary, with the above configuration, this confirmation can be easily performed as follows. That is, as shown in FIG.
Be prepared. The measuring device 31 is roughly divided into a pseudo magnetic disk plate 32 formed of a transparent material, a rotary drive mechanism 33 for rotationally driving the pseudo magnetic disk plate 32, and an optical interferometer 34. The optical interferometer 34 includes a light source device 35 for irradiating a predetermined range of the lower surface of the pseudo magnetic disk plate 32 with monochromatic light or white light, and a beam splitter 36 interposed between the light source device 35 and the pseudo magnetic disk plate 32.
And a microscope 37 for observing the reflected light from the side of the pseudo magnetic disk plate 32 obtained through the beam splitter 36 and a camera 38 for photographing it. Using this measuring device 31, measurement is performed as follows. That is, first, the negative pressure slider 6 with a magnetic head incorporated in an actual magnetic disk device is mounted on the suspension mechanism 7.
The conditions for assembling together are set and set on the pseudo magnetic disk plate 32 as shown in FIG. When the pseudo magnetic disk plate 32 is rotated at a prescribed number of revolutions in this state, a compressed air flow is formed between the pseudo magnetic disk plate 32 and the sliding surface K of the negative pressure slider 6, and this dynamic pressure causes the negative pressure slider 6 to move. Emerges. At this time, when light is emitted from the light source device 35 and the bottom surface of the negative pressure slider 6 is observed by the microscope 37, interference fringes A are observed on the mirror surface portion 14 of the negative pressure surface, as shown in FIG. In this case, since the mirror surface portion 14 is separated from the sliding surface 13 by a minute step S of 1 μm on the side opposite to the disk surface, even if the flying height of 6 is 0.1 μm or less, the interference fringe A is always formed on the mirror surface portion 14. Can be observed. Therefore, the interference fringe A can be used to obtain the clearance between the pseudo magnetic disk plate 32 and the mirror surface portion 14 by a known method, and the minute step S between the mirror surface portion 14 and the sliding surface 13 can be determined. Since it is known, the flying height of the negative pressure slider 6 can be known.

As described above, even if the flying height of the negative pressure slider 6 is 0.1 μm or less, the flying height can be reliably measured. Therefore, whether or not high density recording can be realized when this slider is installed in an actual device is determined. Can be easily tested. Therefore, it is possible to contribute to the appearance of a highly reliable device that realizes high-density recording, and in the end, it is possible to exert the above-mentioned effects.

The present invention is not limited to the above embodiment. Various negative pressure surfaces can be considered such as an inclined surface 17 with respect to the positive pressure generation surface (Fig. 5). Further, the maximum value of the minute step S is empirically 2 μm when white light is used as the light source. Is the limit. Further, a thin film head may be used as the magnetic head. In addition, various modifications can be made without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a magnetic disk device according to an embodiment of the present invention, FIG. 2 is a perspective view showing a slider in the same device, and FIG. 3 is an example of a device for measuring the flying height of the slider. FIG. 4 is a diagram for explaining, FIG. 4 is a diagram showing an example of interference fringes observed on the bottom surface of the slider when the flying height is measured by an optical interference method, and FIG. 5 is a diagram showing a modified example of the slider. 1 ... magnetic disk plate, 2 ... axis, 3 ... rotary drive source,
4 ... Control device, 5 ... Magnetic head, 6, 6a ... Slider, 7 ... Suspension mechanism, 8 ... Access arm, 9 ... Carriage, 10 ... Actuator, 13 ...
Planing surface, 14 ... Negative pressure mirror surface, 16 ... Thin film magnetic head, 17 ...
… Inclined negative pressure mirror surface.

Claims (1)

[Claims] 1. A magnetic disk that is rotationally driven, and a slide that is movably provided along the surface of the magnetic disk and that is levitated on the surface of the magnetic disk by a dynamic pressure generated as the magnetic disk rotates. A magnetic disk device comprising: a slider having a surface formed thereon; and a magnetic head fixed to the slider for writing and reading information to and from the magnetic disk, wherein the slider is the magnetic disk with respect to the sliding surface. 2. A magnetic disk device comprising a negative pressure generating surface formed with a step of 0.1 to 2 μm in a direction away from the negative pressure generating surface, and the negative pressure generating surface is configured as a mirror surface.