Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
1999-08-03
2003-09-30
Evans, Jefferson (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
C360S235700, C360S236100, C360S236300
Reexamination Certificate
active
06628480
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention concerns magnetic head sliders (the sliders is not contacting but flying when said sliders drive on magnetic disks in this specification), which reduce head slider flying height (in the following, only flying height) in the high altitudes, when flying height over magnetic disk full face of magnetic head slider in the flatland low altitudes is approximately equalized, and concerns a magnetic disk unit using it.
It is important to narrow flying height defined as a clearance between a magnetic disk which rotates and a magnetic head slider in order to attempt high recording density of the magnetic disk apparatus. It is also desired that flying height is approximately equalized over the magnetic disk full face.
Narrowing of flying height increases the possibility of contacting the magnetic head to the magnetic disk and the magnetic head slider crashes, and there is the danger of destroying record information on the magnetic disk when both contact conditions are very inferior.
Therefore, from the viewpoint of the improvement in the recording density, decreasing flying height of the magnetic head slider is wanted, and the contradictory demand is wanted from the viewpoint of the reliability of the magnetic disk apparatus.
Laid open 6-325530 and laid open 6-333354 are examples of the conventional technology whose flying height is approximately equalized over the magnetic disk full face. In the laid open 6-325530, a positive pressure slider equalizes flying height over a magnetic disk full face approximately by using a shallow step bearing of 0.7 &mgr;m or less. Laid open 6-333354 a negative pressure slider equalizes flying height over a magnetic disk full face approximately by using a combination of barreled side rail with the cross rail of magnetic head slider which is postponed in the cross-direction.
(1) Dispersion of flying height by processing dispersion (slight difference between the sliders which made up) of magnetic head slider, (2) lowering of flying height by the seek operation, (3) lowering of flying height by atmospheric pressure lowering in the highland, etc. must be respectively reduced in order to narrow flying height of magnetic head slider, while the reliability of the magnetic disk apparatus is kept.
Especially, flying height lowers by the increase of the aerial mean free path (the length which the air moleculars advance during the collisions between air moleculars) which is working fluid e.g. air of the magnetic head slider, when the magnetic disk apparatus is used in the highland, if it says about (
3
) in addition. Moreover, the effect on the reliability of the magnetic disk apparatus which is affected by the lowering of flying height caused by the lowering of atmospheric pressure is great, because magnetic head slider will keep be operated at flying height which always lowers.
Then, it is an important problem that the lowering quantity of flying height in the highland is to be reduced as less as possible and the lowering quantity is to be maintained equivalent over magnetic disk full face in the flatland to say noting of equalizing quantity of flying height (the levitation profile) over magnetic disk full face in the flat ground, as the narrowing of flying height promotes.
Laid open 6-325530 showed a positive pressure slider and laid open 6-333354 showed a negative pressure slider, both of them equalizes flying height over the magnetic disk full face in the flatland approximately, and can reduce flying height change by the processing dispersion and seek operation. However analyzed by the present inventors, the improvement on the above points was desired until now, without considering the flying height lowering in the highland at all.
SUMMARY OF THE INVENTION
This invention considered for the request like the above, the purpose of this invention is that the lowering effect of flying height in the highland (high altitude) is to be reduced and the lowering quantity (effect) is to be maintained equal or uniform over the magnetic disk full face in the flatland (low altitude), when the levitation profile in the flatland is approximately equalized, and a magnetic head slider in which to fix the levitation lowering quantity approximately is possible and magnetic disk apparatus using it.
As the features of this invention is as follows. In order to solve above subjects, in magnetic head slider which comprises with leading edge and air bearing surface and trailing edge. The front step bearing with depth of the submicron that said air bearing surface was made from said leading edge in the continuity. The rail level made from this the front step bearing in the continuity. Recess which is more profound than said front step bearing made in the continuity-from this rail level. Side step bearing with the depth which is identical with said front step bearing made in the continuity from the said rail level. Magnetic head slider which makes that the ratio of depth R of said recess and depth &dgr; s of said front step bearing is R/&dgr; s>5 as being negative pressure slider.
And, the ratio of depth R of said recess and depth &dgr; s of said front step bearing is R/&dgr; s>5 in this slider which having magnetic head slider and magnetic disk and spindle motor, and in the magnetic disk apparatus in which largest peripheral speed which is determined from diameter of said magnetic disk and rotational frequency of the said spindle motor is 20 m/s or less, said magnetic head slider is magnetic head slider which having leading edge and air bearing surface and trailing edge. Negative pressure slider which having side step bearing with the depth which is identical with said bearing that said air bearing surface was made in the continuity from the front step bearing of submicron made from said leading edge in the continuity with the depth and rail level made from this bearing in the continuity and recess which is more profound than said bearing made in the continuity from this rail level and said rail level. The ratio of depth R of aforesaid recess and depth &dgr; s of said front step bearing was made to be R/&dgr; s>5, and again, depth &dgr; s of said front step bearing was made small from 200 nm.
In addition, magnetic disk apparatus in which largest peripheral speed that it having magnetic head slider and magnetic disk and spindle motor and determines from diameter of said magnetic disk and rotational frequency of the said spindle motor is 60 m/s or less, said magnetic head slider is magnetic head slider which having leading edge and air bearing surface and trailing edge. Negative pressure slider which having side step bearing with the depth which is identical with said bearing that said air bearing surface was made in the continuity from the front step bearing of submicron made from said leading edge in the continuity with the depth and rail level made from this bearing in the continuity and recess which is more profound than said bearing made in the continuity from this rail level and said rail level. The ratio of depth R of aforesaid recess and depth &dgr; s of said front step bearing was made to be R/&dgr; s>5, and again, depth &dgr; s of said front step bearing and side step bearing was made to be 400 nm or less over 200 nm.
REFERENCES:
patent: 5704715 (1998-01-01), Chang et al.
patent: RE35800 (1998-05-01), Chapin
patent: 5777825 (1998-07-01), Dorius
patent: 5872686 (1999-02-01), Dorius et al.
patent: 6021020 (2000-02-01), Itoh et al.
patent: 6023394 (2000-02-01), Ito et al.
patent: 6055128 (2000-04-01), Dorius et al.
patent: 6069769 (2000-05-01), Dorius et al.
patent: 6125005 (2000-09-01), Lee et al.
patent: 6-325530 (1994-11-01), None
patent: 6-333354 (1994-12-01), None
Endo Masayoshi
Hashimoto Kiyoshi
Higuchi Shinsuke
Iida Akira
Kohira Hidekazu
Evans Jefferson
Hitachi , Ltd.
Mattingly Stanger & Malur, P.C.
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