Patent US4899240A successfully refreshed from Google Patents.
US4899240A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biasing for a UMR head
Assignee: Eastman Kodak Co
•
Filing: 1988-07-28
•
Granted: 1990-02-06
•
Expires: 2008-07-28
Abstract
Abstract Both hard and easy axis bias fields are applied to the sense film of an unshielded magnetoresistive (UMR) magnetic head by a single bias source. The easy and hard axis fields are applied to the UMR sense film by so angling the applied bias field that orthogonal components of the field lie, respectively, in the directions of the easy and hard axes of the film.
Inventors
- 👤 Richard J. McClure
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:28
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
107 words
A substantially unshielded magnetoresistive head comprising a. an elongated thin-film structure having an easy axis of magnetization that is generally along the length of said film, and having a hard axis of magnetization that is generally in the plane of and perpendicular to the easy axis of the film, and b. single magnetic means in proximity to said film and having a composite field exiting therefrom which has first and second field components cooperative with said film, said first field component being in the direction of the easy axis of said film, and said second component being in the direction of the head axis of said film.
Claim 2
Dependent Claim
107 words
A substantially unshielded magnetoresistive head comprising a. an elongated thin-film structure having an easy axis of magnetization that is generally along the length of said film, and having a hard axis of magnetization that is generally in the plane of and perpendicular to the easy axis of the film, and b. single magnetic means in proximity to said film and having a composite field exiting therefrom which has first and second field components cooperative with said film, said first field component being in the direction of the easy axis of said film, and said second component being in the direction of the head axis of said film.
Claim 3
Dependent Claim
33 words
The apparatus of claim 1 wherein said single magnetic means is disposed off the center line of said thin film, thereby to provide a composite field having easy and hard axis biasing components.
Claim 4
Dependent Claim
28 words
The apparatus of claim 2 wherein said single magnetic means is so disposed that its exiting field is generally perpendicular to the information reading edge of said film.
Claim 5
Dependent Claim
28 words
The apparatus of claim 2 wherein said single magnetic means is so disposed that its exiting field is generally parallel to the information reading edge of said film.
Claim 6
Dependent Claim
32 words
The apparatus of claim 1 wherein said single magnetic means is a magnet lying generally the length of said film, closer to said film at one end thereof than at the other.
Claim 7
Dependent Claim
83 words
An unshielded magnetoresistive head comprising a. an elongated magnetoresistive film having an edge that is generally parallel to the easy magnetization axis of said film and adapted to cooperate with a recording medium to read information recorded in said film, and b. single magnetic means having a field exiting therefrom that has first and second components in the plane of said film, a first component being parallel to said information reading edge thereof, and the second component being perpendicular to said first component.
Claim 8
Dependent Claim
83 words
An unshielded magnetoresistive head comprising a. an elongated magnetoresistive film having an edge that is generally parallel to the easy magnetization axis of said film and adapted to cooperate with a recording medium to read information recorded in said film, and b. single magnetic means having a field exiting therefrom that has first and second components in the plane of said film, a first component being parallel to said information reading edge thereof, and the second component being perpendicular to said first component.
Claim 9
Dependent Claim
33 words
The apparatus of claim 6 wherein said single magnetic means is disposed off the center line of said thin film, thereby to provide a composite field having easy and hard axis biasing components.
Claim 10
Dependent Claim
28 words
The apparatus of claim 7 wherein said single magnetic means is so disposed that its exiting field is generally perpendicular to the information reading edge of said film.
Claim 11
Dependent Claim
28 words
The apparatus of claim 7 wherein said single magnetic means is so disposed that its exiting field is generally parallel to the information reading edge of said film.
Claim 12
Dependent Claim
33 words
The apparatus of claim 6 wherein said single magnetic means is a magnet lying generally the length of said film, but closer to said film at one end thereof than at the other.
References Cited (Backward Citations)
US3881190A
Cited
US4052748A
Cited
US4142218A
Cited
US4122505A
Cited
US4103315A
Cited
US4489484A
Cited
US4195323A
Cited
US4321641A
Cited
US4141051A
Cited
US4191977A
Cited
US4556925A
Cited
US4660113A
Cited
US4547824A
Cited
US4535375A
Cited
US4580175A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-05 | 1993-08-07 | 1994-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-05 | 1997-08-07 | 1998-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-05 | 2001-08-07 | 2002-02-06 | $7700.00 | Window Closed / Lapsed |