Dynamic magnetic information storage or retrieval – General recording or reproducing
Reexamination Certificate
2002-01-08
2004-10-05
Hudspeth, David (Department: 2651)
Dynamic magnetic information storage or retrieval
General recording or reproducing
C360S119050, C360S121000, C360S125330, C360S125330
Reexamination Certificate
active
06801379
ABSTRACT:
RELATED APPLICATION DATA
The present application claims priority to Japanese Application(s) No(s). P2001-006750 filed Jan. 15, 2001, which application(s) is/are incorporated herein by reference to the extent permitted by law.
BACKGROUND OF THE INVENTION
The present invention relates to a multi-magnetic recording head, and a magnetic recording method and a magnetic recording apparatus, which use the multi-magnetic recording head. In particular, the present invention relates to a technique of increasing a magnetic recording density of information recorded by a magnetic recording head by configuring the magnetic recording head as a multi-magnetic recording head including a multiplicity of thin film magnetic recording heads.
In recent years, higher magnetic recording density of information recorded on magnetic recording media has been required to increase magnetic recording capacities of the magnetic recording media, and to meet such a requirement, there have been adopted thin film magnetic recording heads suitable for forming narrower recording tracks on magnetic recording media.
To realize higher magnetic recording densities of information recorded on magnetic recording media, that is, larger magnetic recording capacities of the magnetic recording media, it has been required to carry out multi-channel magnetic recording by using a multi-magnetic recording head including a multiplicity of thin film magnetic recording heads.
For example, a known multi-magnetic recording head is configured such that a plurality of thin film magnetic recording heads are arranged on one head substrate (head chip) in such a manner as to be spaced from each other at suitable intervals in the width direction (perpendicular to the gap direction).
FIG. 1
shows a multi-magnetic recording head “a” including two thin film magnetic recording heads “b” arranged in parallel in the width direction.
Each thin film magnetic recording head “b” is composed of a lower magnetic pole “f” and an upper magnetic pole “g” which are stacked on a magnetic shield layer “e” formed on a non-magnetic substrate “c” via an insulating layer “d”. These lower magnetic pole “f” and the upper magnetic pole “g” are two tip portions of a core “h” which is made from a magnetic material and is formed into an approximately U-shape in a side view. A specific gap “i” is formed between these lower magnetic pole “f” and the upper magnetic pole “g”.
A coil “j” is wound around the core “h”. When a current is applied to the coil “j”, a magnetic field is generated in the gap “i” between the lower magnetic pole “f” and the upper magnetic pole “g”, so that a recording track Tr is formed on a magnetic recording medium (magnetic tape or magnetic disk) “k” running in contact with or in the vicinity of the gap “i”.
The above-described related art multi-magnetic recording head “a”, however, has a problem that since a gap between the two thin film magnetic recording heads “b” cannot be made small, a track pitch Tp of the recording tracks Tr formed on the magnetic recording medium “k” becomes relatively large. Accordingly, the related art multi-magnetic recording head cannot record information on a magnetic recording medium at a higher recording density.
To be more specific, since the coil “j” wound around the core “h” necessarily projects sideways from the core “h”, the adjacent thin film magnetic recording heads “b” cannot be arranged in such a manner that the gaps “i” are close to each other because of interference of the coils “j” with each other (see FIG.
2
).
For this reason, the recording tracks Tr formed by the thin film magnetic recording heads “b” of the multi-magnetic recording head “a” cannot be made close to each other, and thereby the track pitch Tp of the recording tracks Tr cannot be made narrow. Accordingly, the related art multi-magnetic recording head cannot record information on a magnetic recording medium at a higher recording density (see FIG.
3
).
SUMMARY OF THE INVENTION
An object of the present invention is to provide a multi-magnetic recording head including a multiplicity of thin film magnetic recording heads, which is capable of increasing a magnetic recording density of information recorded on a magnetic recording medium.
To achieve the above object, according to a first aspect of the present invention, there is provided a multi-magnetic recording head including: a substrate; a pair of first thin film magnetic poles with a specific gap put therebetween, which are stacked over the substrate; and a pair of second thin film magnetic poles with a specific gap put therebetween, which are stacked over the pair of first thin film magnetic poles; wherein the pair of first thin film magnetic poles and the pair of second thin film magnetic poles are offset from each other in the direction nearly perpendicular to the stacking direction.
According to a second aspect of the present invention, there is provided a magnetic recording method of substantially simultaneously forming a plurality of recording tracks by using a multi-magnetic recording head, the multi-magnetic recording head including: a substrate; a pair of first thin film magnetic poles with a specific gap put therebetween, which are stacked over the substrate; and a pair of second thin film magnetic poles with a specific gap put therebetween, which are stacked over the pair of first thin film magnetic poles; wherein the pair of first thin film magnetic poles and the pair of second thin film magnetic poles are offset from each other in the direction nearly perpendicular to the stacking direction.
According to a third aspect of the present invention, there is provided a magnetic recording apparatus including a multi-magnetic recording head, the multi-magnetic recording head including: a substrate; a pair of first thin film magnetic poles with a specific gap put therebetween, which are stacked over the substrate; and a pair of second thin film magnetic poles with a specific gap put therebetween, which are stacked over the pair of first thin film magnetic poles; wherein the pair of first thin film magnetic poles and the pair of second thin film magnetic poles are offset from each other in the direction nearly perpendicular to the stacking direction.
With these configurations, since a plurality of thin film magnetic recording heads are stacked to each other, a width W of the thin film magnetic recording heads can be made small with its accuracy kept at a desirable value, and also an offset between the thin film magnetic recording heads in the width direction, that is, an arrangement pitch P of the thin film magnetic recording heads in the width direction can be made small with its accuracy kept at a desirable value. As a result, the multi-magnetic recording head, and the magnetic recording method and the magnetic recording apparatus, which use the multi-magnetic recording head, according to the present invention are advantageous in increasing a recording density of information recorded on a magnetic recording medium.
According to a fourth aspect of the present invention, there is provided a magnetic recording apparatus including: at least two sets of multi-magnetic recording heads each of which includes a plurality of thin film magnetic recording heads spaced from each other at specific intervals; wherein recording tracks with an unrecorded portion put therebetween are formed by the thin film magnetic recording heads of one of the multi-magnetic recording heads, and a recording track is formed on the unrecorded portion by at least one of the thin film magnetic recording heads of another of the multi-magnetic recording heads.
With this configuration, it is possible to simultaneously form a plurality of recording tracks, and hence to efficiently increase a recording speed of the magnetic recording apparatus.
REFERENCES:
patent: 4001890 (1977-01-01), Kayser
patent: 4622615 (1986-11-01), Desserre
patent: 4685005 (1987-08-01), Fields, Jr.
patent: 5161299 (1992-11-01), Denison et al.
patent: 5598309 (1997-01-01), Tolman
patent: 6108167 (2000-08-01), Tateyama et al.
patent: 57-183617 (1
Ozue Tadashi
Soda Yutaka
Figueroa Natalia
Hudspeth David
Sonnenschein Nath & Rosenthal LLP
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