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US4754354A
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Ferrite film insulating layer in a yoke-type magneto-resistive head
Assignee: Eastman Kodak Co
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Filing: 1986-05-05
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Granted: 1988-06-28
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Expires: 2006-05-05
Abstract
Abstract A yoke-type magneto-resistive head employs a thin magnetic film structure to bridge a gap in the flux conducting structure of the head and thereby sense magnetic flux. The invention provided means for reducing the magnetic reluctance of the interface between the magnetic film structures and the flux conducting structure of the head, to improve the coupling of magnetic flux from the flux conducting structure to the magnetic film structure and thereby increase the sensitivity of the magneto-resistive head.
Inventors
- 👤 Frederick J. Jeffers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:28
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3916; G11B5/3919; G11B5/3922; G11B5/3925
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
113 words
A magneto-resistive head comprising: a. a magnetic substrate b. a magnetically permeable layer deposited on said substrate, one end of said permeable layer being spaced from said substrate to form therewith a transducer gap, the other end of said permeable layer having good magnetic conductivity into said substrate, said permeable layer being discontinuous so as to form between parts thereof a flux sensing space, c. a magneto-resistive element disposed across said flux sensing space of said permeable layer, and d. an interposed layer in direct contact with and lying between said magneto-resistive element and said permeable layer, said interposed layer being a magnetic conductor having relatively high magnetic permeability and an electrical insulator.
Claim 2
Dependent Claim
113 words
A magneto-resistive head comprising: a. a magnetic substrate b. a magnetically permeable layer deposited on said substrate, one end of said permeable layer being spaced from said substrate to form therewith a transducer gap, the other end of said permeable layer having good magnetic conductivity into said substrate, said permeable layer being discontinuous so as to form between parts thereof a flux sensing space, c. a magneto-resistive element disposed across said flux sensing space of said permeable layer, and d. an interposed layer in direct contact with and lying between said magneto-resistive element and said permeable layer, said interposed layer being a magnetic conductor having relatively high magnetic permeability and an electrical insulator.
Claim 3
Dependent Claim
16 words
The magneto-resistive head of claim 1 wherein said interposed layer is comprised of a ferrite film.
Claim 4
Dependent Claim
16 words
The magneto-resistive head of claim 2 wherein said ferrite film is Fe 3 O 4 .
Claim 5
Dependent Claim
96 words
A magneto-resistive head comprising: a. a magnetic substrate, b. a first insulating layer formed on said substrate. c. a thin film magneto-resistive element deposited on said first insulating layer, d. a multipurpose layer deposited on said magneto-resistive element, said multipurpose layer being a magnetic conductor having relatively high magnetic permeability and an electrical insulator, and e. a discontinuous permeable member deposited over said multipurpose layer, said permeable member being spaced from said substrate at one end to form a transducer gap and the other end of said permeable layer having good magnetic conductivity into said substrate.
Claim 6
Dependent Claim
96 words
A magneto-resistive head comprising: a. a magnetic substrate, b. a first insulating layer formed on said substrate. c. a thin film magneto-resistive element deposited on said first insulating layer, d. a multipurpose layer deposited on said magneto-resistive element, said multipurpose layer being a magnetic conductor having relatively high magnetic permeability and an electrical insulator, and e. a discontinuous permeable member deposited over said multipurpose layer, said permeable member being spaced from said substrate at one end to form a transducer gap and the other end of said permeable layer having good magnetic conductivity into said substrate.
Claim 7
Dependent Claim
19 words
The magneto-resistive head as claimed in claim 4 wherein said second insulating layer is comprised of a ferrite film.
Claim 8
Dependent Claim
16 words
The magneto-resistive head of claim 5 wherein said ferrite film is Fe 3 O 4 .
Claim 9
Dependent Claim
76 words
In a yoke-type magneto-resistive head having a transducer gap, a flux sensing space remote from said transducer gap and a thin magneto-resistive film disposed across said flux sensing space, the improvement comprising an electrically non-conductive layer that is a magnetic conductor having relatively high magnetic permeability in direct contact with and lying between the magneto-resistive film and the yoke structure of the magneto-resistive head to reduce the magnetic reluctance between the head and the magneto-resistive film.
Claim 10
Dependent Claim
76 words
In a yoke-type magneto-resistive head having a transducer gap, a flux sensing space remote from said transducer gap and a thin magneto-resistive film disposed across said flux sensing space, the improvement comprising an electrically non-conductive layer that is a magnetic conductor having relatively high magnetic permeability in direct contact with and lying between the magneto-resistive film and the yoke structure of the magneto-resistive head to reduce the magnetic reluctance between the head and the magneto-resistive film.
Claim 11
Dependent Claim
17 words
The magneto-resistive head of claim 7 wherein said electrically non-conductive layer is comprised of a ferrite film.
Claim 12
Dependent Claim
18 words
The magneto-resistive head as claimed in claim 8 wherein said ferrite film is Fe 3 O 4 .
References Cited (Backward Citations)
US4150408A
Cited
US4425593A
Cited
US4489357A
Cited
US4613918A
Cited
US4477319A
Cited
JPS6050612A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-28 | 1991-12-28 | 1992-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-28 | 1995-12-28 | 1996-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-28 | 1999-12-28 | 2000-06-28 | $7700.00 | Window Closed / Lapsed |