JPH06139681A - Magnetic head - Google Patents

Abstract

PURPOSE:To enable high-density recording by forming the recording medium- facing end face of a magnetic head slider as a part of a spherical surface having a specific radius of curvature and forming rails of a specific width consisting of plural grooves in an air flow direction there by floating stably the head slider and decreasing the floating quantity. CONSTITUTION:The magnetic head 10 is constituted of the magnetic head slider 2 and two electromagnetic conversion elements 1, 1' which expose a magnetic gap layer on the recording medium-facing end face of the slider. The front end face 21 is formed as a part of the spherical surface of 60mm<R<200mm radius R of curvature and two pieces of the grooves 3, 3' are formed in the air flow direction of an arrow K direction, by which the rails A are constituted. The area ratio of the area of the surfaces of the grooves 3, 3'/the total front end area inclusive of the surfaces of the grooves 3, 3' is specified to >=0.3 and <0.5 and the width Aw of the rails A is specified to >=10mum and <300mum. The length L of the slider 2 is specified to 2.8mm, the width to 2.2mm and the depth of the grooves 3, 3' to 50mum. As a result, the floating is stabilized and the floating quantity is decreased. The high-density recording is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head, and more particularly to a magnetic recording medium used in a magnetic storage device for an electronic computer or the like, which is an SSR (Stretched Surface).
Recording) relates to a magnetic head used for recording / reproducing of a medium.

[0002]

2. Description of the Related Art An SSR disk, which is a medium for SSR, has a disk film having a magnetic layer formed as a recording medium by coating or sputtering on a film substrate such as a polyethylene terephthalate film or a polyimide film, This disc film is a disc-shaped disc which is stretched on an annular frame under a constant tension, fixed by pasting or the like, and rotationally driven by the power for driving the annular frame.

The magnetic head for SSR, which is the object of the present invention, receives an air flow by the rotation of the SSR disk and floats on the disk to access the magnetic layer.

A conventional magnetic head for SSR is disclosed in US Pat. No. 4,809,104. In this publication, a surface facing the SSR disk is formed as a part of a spherical surface, the radius R of the spherical surface is 102 mm, and the facing surface has a rectangular shape with a lateral width of 3.2 mm and a total length of 4.3 mm. There are 4 vertical grooves (width 0.15 mm) in the air flow direction on the facing surface of this slider.
It is shown that they are distributed. Further, in these four grooves, the distance between the two inner grooves is approximately 0.3 mm, and the distance between the inner groove and the outer groove is approximately 0.2 mm.

In the above publication, the flying height of the flying head slider having the above-mentioned shape and size is 0.1 μm to 0.1 μm.
There is a disclosure to obtain 5 μm.

[0006]

With the recent increase in recording density of magnetic storage devices, the flying height of a magnetic head of a magnetic storage device, which is generally equipped with a floating head slider such as a hard disk drive, is reduced. As it becomes smaller, levitation stability becomes a particularly important factor. In particular, in a magnetic head for an SSR disk in which the magnetic head and the disk collide and vibrate, the flying height is likely to change because the medium has a film structure. It will be.

However, the conventional magnetic head generally cannot be used with a reduced flying height because the flying height is not stable even when an attempt is made to reduce the flying height for high density recording. Further, the friction between the SSR disk and the magnetic head is large, and the durability of these is reduced.

It is an object of the present invention to provide a magnetic head capable of high density recording by solving the above problems of the prior art.

[0009]

According to the present invention, the above object can be achieved by the following magnetic head.

A magnetic head comprising a magnetic head slider, wherein a front end surface of the slider facing the recording medium is formed as a part of a spherical surface having a radius of curvature R of 60 mm <R <200 mm, and in the air flow direction. Having a rail obtained by forming at least two grooves, (area of groove surface) /
The area ratio of (the area of all the tip surfaces including the surface of the groove) is 0.3 or more and less than 0.5, and the width of the rail is 10 μm or more and 3
A magnetic head having a thickness of less than 00 μm.

The radius of curvature R is preferably 100 mm ≦
R ≦ 150 mm. In this region, the friction between the magnetic head and the SSR medium becomes smaller, so
The durability of the magnetic head and the medium for SSR can be improved.

The radius of curvature R is 60 mm or less or 200
If it is more than mm, the friction between the SSR disk and the magnetic head becomes large, and the durability of these becomes low.

When the area ratio is less than 0.3 or more than 0.5, the friction between the SSR disk and the magnetic head is large, or the SSR disk is scratched, which is not practical. The surface of the groove constitutes a part of the spherical surface having the specific radius of curvature together with the front end surface facing the recording medium.

When the width of the rail is 300 μm or more, the flying height fluctuates due to the change in the rotation speed of the SSR disk, and the flying stability cannot be obtained. The width of the rail is preferably 250 μm or less. Also, from the practical point of view, the width of the rail is 10 μm or more.

[0015]

A magnetic head of the present invention comprises a magnetic head slider, and the end surface of the gap layer of the electromagnetic conversion element portion is preferably the recording medium facing end surface near the air outflow end of the slider. It is provided so as to be exposed to the outside, and more preferably, it is provided so as to include the central axis of the tip surface in the width direction of the magnetic head (the direction perpendicular to the air flow direction).

The rail is defined by at least two grooves parallel to the air flow, and by forming three or more grooves, it is possible to form as many rails as the number of grooves. The rail is preferably provided so as to include the central axis of the tip end surface in the width direction of the magnetic head. The end face of the gap layer may be provided beyond the width of the rail.

[0017]

【Example】

(Embodiment 1) An embodiment of the magnetic head of the present invention will be described with reference to FIG. The magnetic head 10 is composed of a magnetic head slider 2 and two electromagnetic conversion elements 1 and 1'that expose the end surface of the magnetic gap layer to a recording medium facing front end surface 21 of the slider. These elements are exposed on the tip surface near the air outflow end of the slider. The electromagnetic conversion element 1
Only one of them and 1'may be used, and if necessary, three or more may be used.

The tip surface has a radius of curvature R (60 mm <R
It has a rail A which is formed as part of a <200 mm) spherical surface and which is obtained by forming two grooves 3 and 3'in the direction of air flow indicated by arrow K. (Area of surface of grooves 3 and 3 ') / (Area of all tip surfaces including surfaces of grooves 3 and 3')
The area ratio (groove occupancy rate) Sr is 0.3 ≦ Sr <0.5. The rail A is a rail (center rail) including the central axis of the tip surface in the direction perpendicular to the air flow direction.
Is. The width Aw of the rail A is 10 μm ≦ Aw <300
μm.

The length L of the slider in the air flow direction is 2.8 mm, the width W of the slider in the direction perpendicular to the air flow direction is 2.2 mm, and the depths of the grooves 3 and 3'are the same. Each is 50 μm.

The effects of specifying the radius of curvature R, the rail width Aw, and the groove occupancy Sr will be described below.

(Effect by Specifying Radius of Curvature R) In the magnetic head of the first embodiment, each magnetic head having a radius of curvature R of 60 mm (comparative example), 100 mm (example) and 200 mm (comparative example), Medium for SSR (medium tension 100 g / mm, 200 g / mm and 300 g / m
The coefficient of friction with m) was measured by the method described below.

The obtained friction coefficient is shown in Table 1. As the friction coefficient increases, the durability of the magnetic head and the medium deteriorates. In the case of the friction coefficient measured by the method described below, if it is less than 0.5, no practical problem occurs,
The durability of the magnetic head and the medium is good.

According to Table 1, the radius of curvature R is 60 mm <R
In the case of <200 mm, it can be seen that the friction coefficient can be less than 0.5, so that the durability of each of the magnetic head and the SSR medium is not reduced.

[0024]

[Table 1]

(Effects of Specifying Rail Width Aw) In the magnetic head of the first embodiment, (a) center rail width Aw = 199 μm, radius of curvature R = 100 mm (embodiment), (b) center rail width Aw = 300 μm , Radius of curvature R = 102 mm (comparative example), (c) center rail width Aw = 400 μm, radius of curvature R = 103 mm (comparative example), (d) center rail width Aw = 501 μm, radius of curvature R = 100 mm (comparative example) Using each of the magnetic heads, the medium for SSR (medium tension 138 g / mm)
The floating state at the time of rotating from low speed to high speed (500 rpm, 1500 rpm and 3500 rpm) was observed and evaluated by the method described below. These results are shown in FIG.
~ (D).

According to FIG. 2, the center rail width is 199.
In the case of μm ((a) of FIG. 2), unlike the case of center rail widths of 400 μm and 501 μm ((c) and (d) of FIG. 2) in which the interference fringes significantly change depending on the medium rotation speed, It can be seen that there is almost no change in the interference fringes regardless of the number of rotations, and the surface is stably floating at a constant height. Further, when the center rail width is 300 μm ((b) of FIG. 2), the interference fringes of the center rail fluctuate for the first time at high speed rotation of 3500 rpm. Therefore, according to FIGS. 2A and 2B, the center rail width Aw is slightly narrowed from 300 μm (Aw <300 μm) to stabilize the medium rotation speed from low rotation speed to high rotation speed. It can be seen that surfacing can be obtained.

(Effect by Specifying Groove Occupancy Sr) In the magnetic head of the first embodiment, the radius of curvature R is 100 m.
m, the center rail width Aw is 200 μm, and the groove occupancy Sr is 0.3 (Example), 0.4 (Example), 0.5 (Comparative Example) and 0.6 (Comparative Example), respectively. Each magnetic head and the medium for SSR (medium tension 100 g /
mm, 200 g / mm and 300 g / mm) were measured by the method described below. The obtained friction coefficient is shown in Table 2.

According to Table 2, the groove occupation ratio Sr is 0.3 ≦ S.
It can be seen that when r <0.5, the friction coefficient can be made less than 0.5, so that the durability of the magnetic head and the medium for SSR is not deteriorated.

[0029]

[Table 2]

(Measurement Method of Friction Coefficient between Magnetic Head and SSR Medium) As the SSR medium, a perpendicular medium Co is used.
-Having a disk film in which a Cr magnetic layer is formed on a film substrate,
The tension of the disk membrane is 100 g / m under the pushing load.
m, 200 g / mm and 300 g / mm were used. Then, these mediums for SSR are rotated at a low speed of 0.2 m / s, and the recording medium facing surface of the magnetic head and the SS
The coefficient of friction with the R medium was measured.

The pushing load is the load required to push the disc film 1 mm with the needle tip. Pushing load is 1
If it is less than 00 g / mm, the disc film is slackened, and if it exceeds 300 g / mm, the disc film is excessively extended and becomes nonuniform.

(Evaluation Method of Floating State of Magnetic Head) SSR used in the above-mentioned friction coefficient measuring method except that there is no magnetic layer.
Medium (however, medium tension 138 g / mm) 500 rp
m, 1500 rpm and 3500 rpm respectively, and photographed the flying state of each magnetic head (photographed while striking white light with a strobe), and the change in interference fringes of the magnetic head on the recording medium facing surface in the obtained photograph The floating state was evaluated by.

That is, it was evaluated that the smaller the change in the interference fringes with respect to the rotational speed of the medium, the higher the flying stability, and conversely, the larger the change in the interference fringes, the more the flying height fluctuates.

[0034]

The magnetic head of the present invention comprises a magnetic head slider, and the tip end surface of the slider facing the recording medium is formed as a part of a spherical surface having a radius of curvature R of 60 mm <R <200 mm, and The rail has a rail obtained by forming at least two grooves in the air flow direction, and the area ratio of (area of surface of groove) / (area of total tip surface including surface of groove) is 0.3 or more and not less than 0. Less than 5 and the width of the rail is 10μ
m and less than 300 μm, magnetic head and SSR
The floating stability can be secured without lowering the durability of the medium for use, and the floating amount can be reduced before use. Therefore, high density recording becomes possible.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a magnetic head of the present invention.

FIG. 2 is a diagram showing interference fringes on the recording medium facing surface of the magnetic head with respect to the rotation speed of the SSR medium.

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[Procedure amendment]

[Submission date] October 13, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 3

[Correction method] Added

[Correction content]

FIG. 3 is a diagram showing interference fringes on the recording medium facing surface of the magnetic head with respect to the rotation speed of the SSR medium.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 4

[Correction method] Added

[Correction content]

FIG. 4 is a diagram showing interference fringes on the recording medium facing surface of the magnetic head with respect to the rotation speed of the SSR medium.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 5

[Correction method] Added

[Correction content]

FIG. 5 is a diagram showing interference fringes on the recording medium facing surface of the magnetic head with respect to the rotation speed of the SSR medium.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

Claims (2)

[Claims] 1. A magnetic head comprising a magnetic head slider, wherein a tip end surface of said slider facing a recording medium is formed as a part of a spherical surface having a radius of curvature R of 60 mm <R <200 mm, and an air flow. Having a rail obtained by forming at least two grooves in the direction, (area of groove surface) /
The area ratio of (the area of all the tip surfaces including the surface of the groove) is 0.3 or more and less than 0.5, and the width of the rail is 10 μm or more and 3
A magnetic head having a thickness of less than 00 μm. 2. The radius of curvature R is 100 mm ≦ R ≦ 150.
The magnetic head according to claim 1, wherein the magnetic head has a size of mm.