Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
1999-12-30
2001-02-20
Cao, Allen T. (Department: 2754)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
Reexamination Certificate
active
06191923
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a magnetic head slider assembly for a magnetic disk recording/reproducing apparatus. More particularly, the invention is concerned with a magnetic head slider assembly which is profitably suited for realizing a high density recording with a small gap (floating height) between a magnetic head and a magnetic disk or with a contact recording. Furthermore, the invention is also concerned with a method of manufacturing the magnetic head slider assembly and a magnetic disk recording/reproducing apparatus incorporating the same.
As the magnetic head slider assembly of the type mentioned above, there is known a structure in which pads are provided on a surface of a magnetic head slider assembly. By way of example, there is disclosed in JP-A-6-36488 such a structure of the magnetic head slider assembly in which a pair of pads or rails (referred to as a floating surface (
3
) in the above publication) are provided on a slider body for generating a floating force. This floating surface (
3
) is so formed as to cover continuously a magnetic transducer and a thin film layer provided at a rear end portion of the floating surface (
3
). On the other hand, an aerodynamic supporting type magnetic head slider assembly is disclosed in JP-A-6-52645, which assembly is provided with a pair of pads disposed at opposite sides, respectively, and a pad disposed at a rear end portion, wherein these pads are partitioned or delimited by recesses or spaces with a view to reducing the size and the weight of implementing the magnetic head slider assembly as a whole. Of these pads, the one provided at the rear end portion of the magnetic head slider assembly is so formed as to present a continuous surface which covers the slider body, a magnetic transducer (magnetic head) and a thin film and formed of a same material as the main body of a slider. For more particulars, reference should be made to JP-A-652645,column 6, lines 15 to 21 and 24 to 27.
Furthermore, in the case of the magnetic head slider assembly disclosed in JP-A-6-68632, such a side rail structure is adopted which includes protrusions (
51
) and (
52
) disposed adjacent to the thin film head and elongated rail portions disposed at a leading or entrance side of the magnetic head slider assembly as viewed in the direction in which a magnetic medium is moved or rotated relative to the magnetic head slider assembly with a view to protecting the top surface of the side rails from injury, wherein the elongated rail portion are isolated from the protrusions (
51
) and (
52
) by an interposed groove. The protrusions (
51
) and (
52
) are formed of a same material as that of the slider body of the magnetic head slider assembly. For more particulars, reference should be made to JP-A-6-68632, column 3, lines 21 to 24 and 45 to 49.
FIG. 13
is a perspective view of a conventional magnetic head slider assembly known heretofore,
FIG. 14
is a view for illustrating conceptually a floating state of the conventional magnetic head slider assembly, and
FIG. 15
is an fragmentary elongated view of
FIG. 14
showing a portion D indicated as encircled therein. In these figures, reference numeral
200
denotes generally the conventional magnetic head slider assembly,
210
denotes a slider body,
220
denotes a magnetic transducer or head,
211
denotes floating pads, and
223
denote cores of the magnetic transducers
220
. Referring to the figures, in the conventional magnetic head slider assembly
200
, floating pads generally denoted by
230
are polished in order to finish smoothly the floating surfaces thereof. In this conjunction, it is noted that the floating pad
211
provided in the slider body
210
and the floating pad
231
provided on the magnetic transducer
220
(including a thin film thereof) differ from each other in respect to the hardness of the materials forming these pads. Consequently, when the floating pads
230
undergoes machining for polishing, a height offset Hd will make appearance between the floating pads
211
and
231
due to the difference in hardness of the materials (refer to FIG.
15
). This height offset Hd will hereinafter be referred to as the process offset. The reason why such process offset makes appearance can be explained by the fact that the floating pad
231
provided on the magnetic transducer
220
is formed of a soft material as compared with the floating pad
211
of the slider body
210
and thus removed away at a higher rate than the latter upon polishing. Such being the circumstances, the process offset Hd is inevitably produced in the pad of the slider body regardless of whether the pad is to serve for generation of the floating force or as the floating surface or the protrusions disposed closer to the thin film head element.
By the way, it is required to reduce the floating height of the magnetic head slider assembly relative to the magnetic disk to a possible minimum in order to realize a high recording density.
In this conjunction, it is noted that when the floating height is decreased, as mentioned above, the floating height Hs of the floating pad provided on the slider body becomes lower than the floating height Hm of a core element
223
of the magnetic head because of the presence of the process offset.
For the reasons mentioned above, when the floating height is further decreased, there may arise such unwanted situation that the pad of the slider body contacts with the magnetic disk before the core (element) of the magnetic transducer (magnetic head) is brought into contact with the surface of the magnetic disk. More specifically, in the case of the prior art magnetic head slider assembly, the floating pad
231
of the magnetic head is provided in continuation or bonding to the pad
211
of the slider body
210
, as described above. As a consequence of this, an end surface of the floating pad
211
of the slider body
210
comes to contact with the magnetic disk surface
5
(
FIGS. 14 and 15
) in precedence to the floating pad
211
of the magnetic head portion. Accordingly, it is impossible to decrease the floating height more than the process offset Hd. Besides, because no physical contact can essentially be realized between the magnetic transducer or head and the magnetic disk, the contact recording is rendered impossible. Such problem equally arises when the contact recording is to be performed with the magnetic head being contacted to the magnetic disk during rotation thereof. It will now be understood that the process offset provides a great obstacle to realization of a high density recording.
SUMMARY OF THE INVENTION
In the light of the state of the art described above, it is an object of the present invention to provide a magnetic head slider assembly which can avoid the influence of a process offset as well as a method of manufacturing the same.
Another object of the present invention is to provide a magnetic disk recording/reproducing apparatus which is capable of performing a high-density recording by decreasing the floating height of a magnetic head slider assembly or solving the problem presenting an obstacle to a contact recording by essentially nullifying the influence of the process offset.
Yet another object of the present invention is to provide a magnetic head slider assembly of a novel and improved structure having only a projecting portion which incorporates therein cores of a magnetic head formed in a thin film of a main body of the slider as well as a method of manufacturing the magnetic head slider assembly.
In view of the above and other objects which will become more apparent as the description proceeds, the present invention is directed to a magnetic head slider assembly which includes a slider body and a magnetic head (also referred to as the magnetic transducer) formed in a thin film layer provided at one side of the slider main body, wherein a floating rail or a pad adapted to contact with a surface of a magnetic disk is provided in the slider body in the form of projection(s) or protrusion(s) extending in
Higashijima Tetsuji
Higashiya Teruyoshi
Higuchi Shinsuke
Mori Kenji
Nagaike Sadanori
Cao Allen T.
Hitachi , Ltd.
Mattingly, Stanger & Malur
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