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US4651248A
Expired / Lapsed
US
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Thin-film magnetic head
Assignee: Hitachi Ltd
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Filing: 1983-06-03
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Granted: 1987-03-17
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Expires: 2003-06-03
Abstract
Abstract A thin-film magnetic head which has a structure wherein a spiral conductor coil having a plurality of turns is disposed between first and second magnetic layers being substantially in parallel with each other, through upper and lower inorganic insulator layers, and in which a part of the outermost turn of the conductor coil is exposed on a face opposite a magnetic recording medium along with the upper and lower inorganic insulator layers, to form a magnetic gap. This head can be readily manufactured by a manufacturing method including the step of forming the outermost turn of the conductor coil on the side of the face opposite the magnetic recording medium so as to be wider than any other part of the conductor coil, and the step of thereafter machining the face opposite the magnetic recording medium so as to expose the outermost turn of the conductor coil on the face opposite the magnetic recording medium. The magnetic head of the present invention is suited to high-density recording, and is high in recording and reproducing efficiencies and also in reliability.
Inventors
- 👤 Kazuo Shiiki
- 👤 Yoshihiro Shiroishi
- 👤 Isamu Yuito
- 👤 Kiminari Shinagawa
- 👤 Hideo Fujiwara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:24
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/3109; G11B5/313; G11B5/3143; G11B5/1278
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
266 words
A thin-film magnetic head including a first magnetic layer which is formed on a nonmagnetic substrate or a magnetic substrate which serves also as a first layer (hereinbelow, the latter substrate shall also be termed "first magnetic layer"), a lower inorganic insulator layer which is formed on said first magnetic layer, a conductor coil of a plurality of turns which is spirally formed on said lower inorganic insulator layer, an upper inorganic insulator layer which is formed on said conductor coil including said lower inorganic insulator layer, said upper inorganic insulator layer having a recess in the upper surface thereof and a convex top, an organic insulator layer which fills the recess of said upper inorganic insulator layer so that said upper inorganic insulator layer and said organic insulator layer together form a combined layer having a flat top surface, the flat top surface including the upper surface of the convex top of the upper inorganic insulator layer, and a second magnetic layer which is formed on said flat top surface of said combined layer; wherein a part of the outermost turn of said conductor coil is exposed on a face confronting a magnetic recording medium and forms a magnetic gap between said first and second magnetic layers along with said upper and lower inorganic insulator layers, said organic insulator layer is not exposed in the vicinity of, at least, the surface of said magnetic gap confronting the magnetic recording medium, and said second magnetic layer lies in contact with said first magnetic layer in a central part of the spiral of the spiral conductor coil.
Claim 2
Dependent Claim
266 words
A thin-film magnetic head including a first magnetic layer which is formed on a nonmagnetic substrate or a magnetic substrate which serves also as a first layer (hereinbelow, the latter substrate shall also be termed "first magnetic layer"), a lower inorganic insulator layer which is formed on said first magnetic layer, a conductor coil of a plurality of turns which is spirally formed on said lower inorganic insulator layer, an upper inorganic insulator layer which is formed on said conductor coil including said lower inorganic insulator layer, said upper inorganic insulator layer having a recess in the upper surface thereof and a convex top, an organic insulator layer which fills the recess of said upper inorganic insulator layer so that said upper inorganic insulator layer and said organic insulator layer together form a combined layer having a flat top surface, the flat top surface including the upper surface of the convex top of the upper inorganic insulator layer, and a second magnetic layer which is formed on said flat top surface of said combined layer; wherein a part of the outermost turn of said conductor coil is exposed on a face confronting a magnetic recording medium and forms a magnetic gap between said first and second magnetic layers along with said upper and lower inorganic insulator layers, said organic insulator layer is not exposed in the vicinity of, at least, the surface of said magnetic gap confronting the magnetic recording medium, and said second magnetic layer lies in contact with said first magnetic layer in a central part of the spiral of the spiral conductor coil.
Claim 3
Dependent Claim
124 words
A thin-film magnetic head as defined in claim 1, wherein said conductor coil is a coil of a plurality of turns, constructed by steps including initially forming the outermost turn of said conductor coil, which is to be exposed on said face of said magnetic head confronting the magnetic recording medium, to have a greater width, in the plane of the coil, than the other turns of said conductor coil, and then reducing the width of the outermost turn of said conductor coil at machining for forming said face of said magnetic head confronting the recording medium, said reducing the width being such that the outermost turn is reduced to at least approximately equal the width of the other turns of said conductor coil.
Claim 4
Dependent Claim
69 words
A thin-film magnetic head as defined in claim 1, wherein a thickness of said first magnetic layer is at least 10 times greater than a shortest wavelength to be recorded, and a thickness of said second magnetic layer is smaller in the vicinity of said face confronting the magnetic recording medium than in any other part thereof and is at most 1/2 of the shortest wavelength to be recorded.
Claim 5
Dependent Claim
22 words
A thin-film magnetic head as defined in claim 1, wherein said upper inorganic insulator layer is thinner than said lower insulator layer.
Claim 6
Dependent Claim
41 words
A thin-film magnetic head as defined in claim 1, wherein a shielding conductor layer is disposed outside said second magnetic layer in the vicinity of, at least, said face confronting the magnetic recording medium, directly or through an inorganic insulator layer.
Claim 7
Dependent Claim
19 words
A thin-film magnetic head as defined in claim 1, wherein said magnetic substrate is an Mn--Zn ferrite single-crystal substrate.
Claim 8
Dependent Claim
40 words
A thin-film magnetic head as defined in claim 1, wherein said second magnetic layer in the vicinity of, at least, said face confronting the magnetic recording medium is made of an alloy containing Fe and Si as a principal constituent.
Claim 9
Dependent Claim
33 words
A thin-film magnetic head as defined in claim 1, wherein said conductor coil is made of an alloy which contains, at least, Cu and Cr; Al and Cr; or Cu, Al and Cr.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-16 | 1990-09-15 | 1991-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-16 | 1994-09-15 | 1995-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-16 | 1998-09-15 | 1999-03-17 | $7700.00 | Window Closed / Lapsed |