US4520076A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1981-05-14
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Granted: 1985-05-28
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Expires: 2001-05-14
Abstract
Abstract A magnetic recording medium has plural magnetic layers on a non-magnetic substrate. The magnetic particles are orientated in substantially the same tilt direction for major axes of the particles in each magnetic layer and in cross tilt directions for major axes of the particles in the adjacent magnetic layers.
Inventors
- 👤 Seitoku Saito
- 👤 Toshiaki Izumi
- 👤 Takayoshi Kobuke
- 👤 Hiroshi Sugihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:43
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/674; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12931; Y10T428/12937; Y10T428/12944; Y10T428/12951
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
105 words
A magnetic recording medium comprising: a non-magnetic substrate; a plurality of magnetic layers deposited on said non-magnetic substrate; said magnetic layers being formed of magnetic particles having a shape with a major axis, said major axis arranged at a tilt angle to the perpendicular of said substrate; wherein the tilt angle of all particles in the same layer is the same and the tilt angle for particles in adjacent layers is equal in magnitude but in opposite directions from said perpendicular, and wherein said major axes of said magnetic particles in the adjacent magnetic layers are crossed at an angle ranging from 20° to 160°.
Claim 2
Dependent Claim
105 words
A magnetic recording medium comprising: a non-magnetic substrate; a plurality of magnetic layers deposited on said non-magnetic substrate; said magnetic layers being formed of magnetic particles having a shape with a major axis, said major axis arranged at a tilt angle to the perpendicular of said substrate; wherein the tilt angle of all particles in the same layer is the same and the tilt angle for particles in adjacent layers is equal in magnitude but in opposite directions from said perpendicular, and wherein said major axes of said magnetic particles in the adjacent magnetic layers are crossed at an angle ranging from 20° to 160°.
Claim 3
Dependent Claim
17 words
The magnetic recording medium according to claim 1 wherein said non-magnetic substrate is made of a polymer.
Claim 4
Dependent Claim
18 words
The magnetic recording medium according to claim 1 wherein said magnetic layer are made of magnetic metallic material.
Claim 5
Dependent Claim
24 words
The magnetic recording medium according to claim 3 wherein said magnetic metallic material is made of one of iron, cobalt, nickel and alloys therof.
Claim 6
Dependent Claim
17 words
The magnetic recording medium according to claim 1, wherein said non-magnetic substrate is made of a metal.
References Cited (Backward Citations)
US4220117A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-27 | 1988-11-26 | 1989-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-27 | 1992-11-26 | 1993-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-27 | 1996-11-26 | 1997-05-28 | $7700.00 | Window Closed / Lapsed |