Dynamic magnetic information storage or retrieval – Head – Head surface structure
Reexamination Certificate
1998-10-02
2002-12-10
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Head surface structure
C360S235200
Reexamination Certificate
active
06493182
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head and more particularly it relates to a magnetic head with which the adhesion phenomenon does not readily occur.
2. Discussion of Background
Magnetic heads in the known art that fly while maintaining a minute distance from the magnetic recording medium by using the dynamic pressure that is generated as the magnetic recording medium travels include, for instance, the magnetic head disclosed in Japanese Examined Patent Publication No. 21329/1983 and the magnetic head in Japanese Examined Patent Publication No. 28650/1983.
Each of the magnetic heads mentioned above that is mounted at the front end of a head support device in a magnetic recording/reproduction apparatus, is driven through the so-called contact start-stop method whereby an operation is started or stopped in a state in which the air bearing surface (hereafter referred to as the ABS) of the slider is placed in spring contact with a front surface of the magnetic disk. While the ABS is pressed against the surface of the magnetic disk due to the spring pressure when the magnetic disk is stationary, a lift dynamic pressure is generated at the ABS of the slider when the magnetic disk rotates so that the magnetic head flies above the surface of the magnetic disk.
In this type of magnetic recording/reproduction apparatus, it is desirable that the flying height of the magnetic head be set at the smallest possible value in order to support high density recording. However, when the flying height of the magnetic head is reduced, the magnetic head tends to collide with the surface of the magnetic head which may result in damage such as a crash.
One means for improving the durability by preventing such a crash is achieved by using a magnetic disk having a high degree of surface smoothness. However, since a lubricant is applied to the surface of the magnetic disk having a high degree of surface smoothness under normal circumstances, the magnetic head becomes adhered to the surface of the magnetic disk with the lubricant acting as the main cause. Furthermore, due to factors such as moisture, water or the like present in the air in addition to the adhering effect of the lubricant, the magnetic head adheres to the surface of the magnetic head with even more force.
Since this type of magnetic recording/reproduction apparatus is driven through the contact start-stop method as described earlier, it cannot be started if such adhesion of the magnetic head occurs.
Various technologies have been proposed in the prior art to constitute means for preventing the adhesion phenomenon. For instance, Japanese Unexamined Patent Publication No. 37874/1988, Japanese Unexamined Patent Publication No. 287440/1996 and Japanese Unexamined Patent Publication No. 2122740/1996 disclose means for reducing the size of the area over which the magnetic disk and the magnetic head come into contact with each other by providing three projections at specific positions at the rail surface. In addition, Japanese Unexamined Patent Publication No. 326150/1995 discloses a means for preventing adhesion by providing minute indentations and projections at the rail surface constituting a portion of the slider base body.
Now, when providing a means for adhesion prevention at the ABS of the slider, it is crucial that it cause little or no change in the flying characteristics achieved through the ABS and that the means for adhesion prevention be provided at the ABS with ease and a high degree of accuracy. The prior art technologies mentioned above do not always satisfy these requirements.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a magnetic head with which the force with which it adheres to the magnetic disk can be reduced.
It is a further object of the present invention to provide a magnetic head provided with a means for adhesion prevention capable of easily controlling the force of adhesion.
It is a still further object of the present invention to provide a magnetic head provided with a means for adhesion prevention capable of minimizing changes in the flying characteristics achieved through the ABS.
It is a still further object of the present invention to provide a magnetic head with which a means for adhesion prevention can be easily and precisely provided at the ABS.
In order to achieve the objects described above, the magnetic head according to the present invention includes a slider and an electromagnetic transducer. The slider is provided with an ABS. The electromagnetic transducer is provided at the slider and its end for electromagnetic conversion is located at a position close to the ABS. The ABS is constituted of a surface of a protective film and a slider base body surface. The protective film, which is laminated. on part of the slider base body surface covers, at least, the end of the electromagnetic transducer.
In the magnetic head according to the present invention, since the protective film is laminated onto the slider base body surface to constitute the ABS, a magnetic head achieving a high degree of frictional resistance is obtained.
In addition, since the protective film covers at least the end of the electromagnetic transducer where electromagnetic conversion is performed, the electromagnetic transducer is protected by the protective film. In particular, when the electromagnetic transducer includes a magnetoresistive element (hereafter referred to as an MR element) which constitutes a read element, the end of the MR element does not come in direct contact with the surface of the magnetic disk so that any leakage and discharge of the sense current to the magnetic disk, or any defective operation resulting from such leakage or discharge can be prevented with a high degree of reliability.
Furthermore, since the protective film is laminated on part of the slider base body surface, a stage corresponding to the film thickness of the protective film is created around the protective film relative to the slider base body surface. In this structure, the surface of the protective film and the slider base body surface constitute the ABS. Thus, the force with which the magnetic head adheres to the magnetic disk can be reduced. In addition, the force with. which the magnetic head adheres to the magnetic disk can be controlled by adjusting the size of the area of the protective film.
Moreover, the protective film which is laminated on part of the slider base body surface, is formed to have various patterns. When patterning a protective film, the required protective film pattern can be formed easily and with a high degree of accuracy by providing the protective film at the slider base body surface and .partially removing the protective film using a pattern that is set in advance through a means such as ion milling.
The present invention further discloses specific desirable examples of the protective film, the thickness of the protective film that minimizes any changes in the flying characteristics, the relationship between the adhesive force and the area of the protective film and the like.
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Koga Keiji
Koyama Akinori
Tanemura Shigeki
Yamanaka Noboru
TDK Corporation
Tupper Robert S.
Watko Julie Anne
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