Patent US4663683A successfully refreshed from Google Patents.
US4663683A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetoresistive thin film head
Assignee: Panasonic Holdings Corp
•
Filing: 1983-11-10
•
Granted: 1987-05-05
•
Expires: 2003-11-10
Abstract
Abstract In a magnetic head which utilizes the magnetoresistive effect of a ferromagnetic thin film, it is possible to realize a magnetoresistive effect type thin film magnetic head with favorable secondary distortion characteristics by forming on at least one surface of the ferromagnetic thin film, a grating forming an angle larger than 60° and smaller than 80° with respect to the direction of the electric current flowing through the thin film. By setting the grating into more than two different directions, a magnetic head capable of functioning at a still smaller distortion is presented.
Inventors
- 👤 Hiroshi Youda
- 👤 Nobuyuki Kaminaka
- 👤 Satoru Mitani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:26
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
111 words
A thin film magnetic head which comprises a film of ferromagnetic magnetoresistive material, means for directing electric current through said ferromagnetic thin film in a first direction, high permeability members provided at opposite sides of said ferromagnetic thin film, and non-magnetic insulating members disposed between said ferromagnetic thin film and said high permeability members, said ferromagnetic thin film having a grating formed in said material on at least one surface thereof on at least one of said opposite sides, said grating being formed of grooves in said at least one surface in a second direction at an angle larger than 60° and smaller than 80° with respect to said first direction.
Claim 2
Dependent Claim
111 words
A thin film magnetic head which comprises a film of ferromagnetic magnetoresistive material, means for directing electric current through said ferromagnetic thin film in a first direction, high permeability members provided at opposite sides of said ferromagnetic thin film, and non-magnetic insulating members disposed between said ferromagnetic thin film and said high permeability members, said ferromagnetic thin film having a grating formed in said material on at least one surface thereof on at least one of said opposite sides, said grating being formed of grooves in said at least one surface in a second direction at an angle larger than 60° and smaller than 80° with respect to said first direction.
Claim 3
Dependent Claim
39 words
A thin film magnetic head as claimed in claim 1, wherein said ferromagnetic thin film has a thickness perpendicular said first and second directions and said grating has a depth smaller than said thickness of said ferromagnetic thin film.
Claim 4
Dependent Claim
33 words
A thin film magnetic head as claimed in claim 1, wherein said ferromagnetic thin film has a nonnegative magnetostriction constant, at least one of said high permeability members having a nonpositive magnetostriction constant.
Claim 5
Dependent Claim
75 words
A thin film magnetic head as claimed in claim 1, wherein the grating has a plurality of regions having grooves extending in respective grating directions which are different from each other, said grating directions of said grooves in respective regions being symmetrical with respect to the direction of a boundary between said regions, each of said grating directions being at an angle less than 80° and greater than 60° with respect to said first direction.
References Cited (Backward Citations)
US3019125A
Cited
US4052748A
Cited
US4142218A
Cited
US4040113A
Cited
JPS5223924A
Cited
US4103315A
Cited
US4321640A
Cited
JPS5597020A
Cited
US4315291A
Cited
US4492997A
Cited
JPS57203219A
Cited
JPS57208624A
Cited
US4503394A
Cited
JPS5814118A
Cited
US4477794A
Cited
US4556925A
Cited
JPS58143403A
Cited
JPS5992419A
Cited
US4535375A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-04 | 1990-11-03 | 1991-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-04 | 1994-11-03 | 1995-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-04 | 1998-11-03 | 1999-05-05 | $7700.00 | Window Closed / Lapsed |