US4164770A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film magnetoresistive head
Assignee: Eastman Kodak Co
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Filing: 1977-09-21
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Granted: 1979-08-14
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Expires: 1997-09-21
Abstract
Abstract A flux sensitive magnetic head is disclosed wherein a thin single domain magnetic film coated on a non-conductor bridges the head gap. A magnetic bias is applied to the hard axis of the film; and flux entering the gap causes the resistivity of the film to vary about a resistance reference established by the bias. The resistance variation is converted to a useful signal corresponding to the flux entering the gap.
Inventors
- 👤 Frederick J. Jeffers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:44
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/17; G11B5/40
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
182 words
In a magnetic playback head of the type having: (a) a pair of magnetic means for defining a transducer gap, and (b) means for producing a signal proportional to flux entering said gap, the improvement wherein said signal producing means comprises: (a) an elongated element connected across said gap, said element being comprised of an electrically non-conductive support and a thin single domain magnetic film coextensively formed thereabout, the easy axis of said film being about the longitudinal axis of said element and in a plane that is perpendicular to said longitudinal axis, (b) means for applying a magnetic bias generally in the direction of the longitudinal axis of said element, so as to tilt the easy axis of said film in the direction of the hard axis of said film and (c) means for detecting resistance changes of said film due to changes in the degree of tilt, said tilt being a function of the flux entering said gap, whereby flux patterns in a magnetic medium with which said head cooperates are directly measurable by virtue of said changes in resistance.
Claim 2
Dependent Claim
182 words
In a magnetic playback head of the type having: (a) a pair of magnetic means for defining a transducer gap, and (b) means for producing a signal proportional to flux entering said gap, the improvement wherein said signal producing means comprises: (a) an elongated element connected across said gap, said element being comprised of an electrically non-conductive support and a thin single domain magnetic film coextensively formed thereabout, the easy axis of said film being about the longitudinal axis of said element and in a plane that is perpendicular to said longitudinal axis, (b) means for applying a magnetic bias generally in the direction of the longitudinal axis of said element, so as to tilt the easy axis of said film in the direction of the hard axis of said film and (c) means for detecting resistance changes of said film due to changes in the degree of tilt, said tilt being a function of the flux entering said gap, whereby flux patterns in a magnetic medium with which said head cooperates are directly measurable by virtue of said changes in resistance.
Claim 3
Dependent Claim
26 words
The apparatus of claim 1 wherein said elongated element has a longitudinal hollow central portion hollow, said hollow central portion having an electrically conductive element therewithin.
Claim 4
Dependent Claim
43 words
The apparatus of claim 2 including means for applying a current through the conductive element within said hollow portion, and heat sink means connected to said electrically conductive element, so as to dissipate heat from said thin film through said electrically non-conductive support.
Claim 5
Dependent Claim
20 words
The apparatus of claim 1 wherein said means for applying a bias is a coil wound about said elongated element.
References Cited (Backward Citations)
US3242269A
Cited
US3239754A
Cited
US3400328A
Cited
US3369083A
Cited
US3443213A
Cited
US3829894A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-08-13 | 1983-02-12 | 1983-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-13 | 1987-02-12 | 1987-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-13 | 1991-02-12 | 1991-08-14 | $7700.00 | Window Closed / Lapsed |