Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
2002-07-19
2003-12-02
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
C360S235700, C360S235800
Reexamination Certificate
active
06657820
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic disk drive and, more particularly, to a magnetic head slider support structure capable of reducing the variation of the floating height or flying height of a magnetic head slider with respect to a rolling direction from a magnetic disk and of improving the approach ability or proximity ability of a magnetic head slider to approach a magnetic disk.
To increase recording density of a magnetic disk drive, it is important to reduce the flying height of a magnetic head slider holding a magnetic head with respect to a rolling direction from a surface of a magnetic disk, i.e., to reduce a clearance between the magnetic head slider and the magnetic disk, and to improve the proximity ability of the magnetic head slider to approach a magnetic disk.
The variation of the static attitude of a suspension supporting the magnetic head slider is a principal cause of variation of the flying height of the magnetic head slider with respect to a rolling direction. If the static attitude around the roll axis of the suspension varies, the magnetic head slider tilts about the roll axis. Consequently, the magnetic head cannot be disposed close to the magnetic disk and the danger of the edge of a slider rail surface coming into contact with the magnetic disk increases.
A related magnetic head slider capable of reducing the variation of the flying height with respect to a rolling direction of the magnetic head slider is disclosed in U.S. Pat. No. 5,825,587. In this magnetic head slider, an outlet end portion of a center rail provided with a magnetic head is formed in a narrow width to reduce the variation of the minimum flying height, i.e., the flying height of the lowest portion of a magnetic head slider, when the magnetic head slider tilts about the roll axis. The lowest portion is the edge of the outlet end portion of a rail surface.
The proximity ability of the slider is the ability of the magnetic head slider to follow roughness and wavinesses formed on the surface of a magnetic disk formed by various causes. Roughness and wavinesses formed on a magnetic disk include, for example, minute irregularities or roughness having wavelengths not greater than several microns and height not greater than several nanometers as measured by an atomic force microscope (AFM); minute undulations (micro-waviness) having wavelengths in the range of several tens micrometers to about 1 mm and height of several nanometers as measured by a laser Doppler vibrometer (LDV); and runouts having wavelengths in the range of several millimeters to several tens millimeters.
Most of minute roughness and minute wavinesses (micro-wavinesses) are those existing on the substrate of the magnetic disk inherently and lapping marks formed by a lapping process. The runouts are formed by distortion when the magnetic disk is clamped. Desirably, a magnetic head slider is capable of properly following any one of those wavinesses. If the magnetic head slider is unable to follow large irregularities, the edge of the outlet end portion of the rail surface at the lowest flying height from a magnetic disk is liable to come into contact with the magnetic disk.
BRIEF SUMMARY OF THE INVENTION
The reduction of the flying height of a magnetic head slider with respect to the entire surface of a magnetic disk, the reduction of the variation of flying height of the magnetic head slider and the improvement of the proximity ability of the magnetic disk slider to approach the magnetic disk are principal matters to be achieved to enhance recording density, maintaining the reliability of a magnetic disk drive.
U.S. Pat. No. 5,825,587 mentions the capability of a magnetic head slider to reduce the variation of its flying height with respect to a rolling direction, but does not describe the proximity ability of the magnetic disk slider to approach a magnetic disk. The improvement of the proximity ability of magnetic head slider has been desired.
The present invention has been made under such circumstances and it is therefore a feature of the present invention to provide a magnetic head slider capable of reducing the variation of its flying height with respect to a rolling direction, namely, static flying height variation, and of improving the proximity ability to approach a magnetic disk, namely, dynamic variation of flying height to follow the magnetic disk.
Another feature of the present invention relates to a magnetic disk drive provided with such a magnetic head slider.
According to an aspect of the present invention, a magnetic head slider has a length between an air inlet end and an air outlet end, and includes: a magnetic head; and a slider rail having a slider rail surface which is contiguous with side surfaces and an air inlet end surface of the magnetic head, a step bearing surface formed on the air inlet side in a predetermined depth from the slider rail surface, and a negative-pressure groove of a predetermined depth from the step bearing surface.
In one embodiment, the magnetic head is supported by a magnetic head mounting surface of the magnetic head mounting member. The slider rail surface includes an end portion disposed near the air outlet end. The end portion extends with the entire width to the magnetic head mounting member near the air outlet end. The width of the end portion may be uniform. The magnetic head mounting member may be a protective film that protects the magnetic head.
In another embodiment, the slider rail surface includes an end portion disposed near the air outlet end. The end portion extends at least to the protective film protecting the magnetic head near the air outlet end. The end portion may include a beveled extension extending from a boundary of the protective film beyond the magnetic head toward the air outlet end and narrowing in width toward the air outlet end.
In another embodiment, the slider rail surface includes an end portion disposed near the air outlet end. The end portion extends to the magnetic head near the air outlet end. The end portion includes a tapered part which has a width continuously increasing from one end adjacent the magnetic head in a direction toward the air inlet end. The end portion may include a uniform part which extends with a uniform width from the tapered part to another end of the end portion in a direction toward the air inlet end.
In this specification, a dimension between an air inlet side and an air outlet side is called a “length” and a dimension perpendicular to the length is called a “width”, and a dimension in a direction from a magnetic disk toward the magnetic head slider is called a “depth” in describing the shape of magnetic head sliders. A state where a magnetic head slider is floating or flying above a magnetic disk to read information from or to write information to the magnetic disk is called “operating state”.
REFERENCES:
patent: 5404256 (1995-04-01), White
patent: 5825587 (1998-10-01), Bolasna et al.
patent: 6144529 (2000-11-01), Wada et al.
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patent: 6396664 (2002-05-01), Koishi et al.
patent: 6424494 (2002-07-01), Koishi
patent: 6462909 (2002-10-01), Boutaghou et al.
patent: 6525909 (2003-02-01), Qian et al.
patent: 6556381 (2003-04-01), Kohira et al.
Kohira Hidekazu
Matsuda Akira
Matsumoto Masaaki
Saegusa Shozo
Tanaka Hideaki
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