US4670356A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magneto-optical recording medium and method of making same
Assignee: Sony Corp
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Filing: 1985-11-29
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Granted: 1987-06-02
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Expires: 2005-11-29
Abstract
Abstract An improved magneto-optical recording medium and a method of making the same, the medium including a substrate base and a magneto-optical recording layer formed on the base and composed of a plurality of layers each of which contains a rare earth metal and a transition metal. The relative concentration ratio between the rare earth metal and the transition metal in the layers varies cyclically in the direction of the thickness of the magneto-optical recording layer. The recording medium is conveniently manufactured by simultaneously depositing the transition metal and the rare earth metal by co-sputtering the two metals on a base and providing relative movement between the base and the metal sources during co-sputtering to produce the multilayer recording structure.
Inventors
- 👤 Noboru Sato
- 👤 Tomiji Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:34
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B5/00; G11B5/84; G11B5/851; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12632; Y10T428/12771; Y10T428/12861; Y10T428/12931
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
71 words
A magneto-optical recording medium comprising: a substrate base and a magneto-optical recording layer formed on said base composed of a plurality of layers, each of said layers containing a rare earth metal and a transition metal, the relative concentration ratio between said rare earth metal and said transition metal in said layers varying cyclically above and below an average value in the direction of the thickness of the magneto-optical recording layer.
Claim 2
Dependent Claim
71 words
A magneto-optical recording medium comprising: a substrate base and a magneto-optical recording layer formed on said base composed of a plurality of layers, each of said layers containing a rare earth metal and a transition metal, the relative concentration ratio between said rare earth metal and said transition metal in said layers varying cyclically above and below an average value in the direction of the thickness of the magneto-optical recording layer.
Claim 3
Dependent Claim
19 words
A recording medium according to claim 1 in which said rare earth metal is Tb or an alloy thereof.
Claim 4
Dependent Claim
19 words
A recording medium according to claim 1 in which said rare earth metal is Gd or an alloy thereof.
Claim 5
Dependent Claim
18 words
A recording medium according to claim 1 in which said transition metal is Fe or an alloy thereof.
Claim 6
Dependent Claim
18 words
A recording medium according to claim 1 in which said transition metal is Co or an alloy thereof.
Claim 7
Dependent Claim
89 words
A magneto-optical recording medium comprising: a non-magnetic base, and a magneto-optical recording medium formed on said base, said medium being composed of a plurality of layers, each composed of at least one rare earth metal and a transition metal in varying amounts in each layer, alternating layers being rich in rare earth metal and the layers between said alternating layers being rich in said transition metal, some rare earth metal being diffused into said transition metal layers and some transition metal being diffused into said rare earth metal layers.
Claim 8
Dependent Claim
89 words
A magneto-optical recording medium comprising: a non-magnetic base, and a magneto-optical recording medium formed on said base, said medium being composed of a plurality of layers, each composed of at least one rare earth metal and a transition metal in varying amounts in each layer, alternating layers being rich in rare earth metal and the layers between said alternating layers being rich in said transition metal, some rare earth metal being diffused into said transition metal layers and some transition metal being diffused into said rare earth metal layers.
Claim 9
Dependent Claim
19 words
A recording medium according to claim 6 in which said rare earth metal is Tb or an alloy thereof.
Claim 10
Dependent Claim
19 words
A recording medium according to claim 6 in which said rare earth metal is Gd or an alloy thereof.
Claim 11
Dependent Claim
18 words
A recording medium according to claim 6 in which said transition metal is Fe or an alloy thereof.
Claim 12
Dependent Claim
18 words
A recording medium according to claim 6 in which said transition metal is Co or an alloy thereof.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-01 | 1990-12-01 | 1991-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-01 | 1994-12-01 | 1995-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-01 | 1998-12-01 | 1999-06-02 | $7700.00 | Window Closed / Lapsed |