Patent US4518657A successfully refreshed from Google Patents.
US4518657A
Expired / Lapsed
US
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Recording medium and recording-reproduction system provided with the recording medium
Assignee: Olympus Corp
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Filing: 1981-10-05
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Granted: 1985-05-21
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Expires: 2001-10-05
Abstract
Abstract A recording medium comprises a first layer prepared from a material of perpendicular anisotropy, a second layer prepared from a compound of noncrystalline rare earth metal--3d transition metal and deposited on said first layer, and a transparent protective layer and mounted on said second layer. Data is magnetically recorded on the recording medium and the recorded data is optically read by utilizing the magneto-optics effects.
Inventors
- 👤 Tuneo Yanagida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:00
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10532; G11B11/10534; G11B11/1055; G11B11/10552; G11B11/10554; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/672; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12771; Y10T428/12861; Y10T428/12931
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
160 words
A recording and reproduction system which comprises: a recording head constituted by main and auxiliary magnetic poles so arranged as to clamp a recording medium which is formed of a first layer comprising a first magnetic alloy material having perpendicular magnetic anisotropy, a high coersive force, a high remnant magnetic flux density and a small anisotropy dispersion angle, a second layer comprising a second magnetic amorphous alloy of a rare earth metal--3d transition metal positioned on said first layer, said second layer having a lower coersive force and higher Curie temperature than said first layer, said first and second alloys being different alloys and one of them containing one constituent element not present in said other alloy; and a protective layer prepared from a transparent nonmagnetic material on said second magnetic layer for recording data on the recording medium by a perpendicular magnetic recording method; and reproduction means for reading data out of the recording medium by the magneto-optics effect.
Claim 2
Dependent Claim
160 words
A recording and reproduction system which comprises: a recording head constituted by main and auxiliary magnetic poles so arranged as to clamp a recording medium which is formed of a first layer comprising a first magnetic alloy material having perpendicular magnetic anisotropy, a high coersive force, a high remnant magnetic flux density and a small anisotropy dispersion angle, a second layer comprising a second magnetic amorphous alloy of a rare earth metal--3d transition metal positioned on said first layer, said second layer having a lower coersive force and higher Curie temperature than said first layer, said first and second alloys being different alloys and one of them containing one constituent element not present in said other alloy; and a protective layer prepared from a transparent nonmagnetic material on said second magnetic layer for recording data on the recording medium by a perpendicular magnetic recording method; and reproduction means for reading data out of the recording medium by the magneto-optics effect.
Claim 3
Dependent Claim
35 words
The recording and reproduction system according to claim 1, wherein a magnetizing wire is wound about the auxiliary magnetic pole; and said magnetizing wire is supplied with magnetizing current corresponding to signals to be recorded.
Claim 4
Dependent Claim
54 words
A recording and reproduction system according to claim 1 or 2, wherein the reproduction means comprises: a light source for projecting light beams on the recording medium; and a light-receiving element for receiving reflections modulated by data recorded in the recording medium, and demodulating said modulated reflections into signals corresponding to said recorded data.
Claim 5
Dependent Claim
122 words
A recording medium comprising a first and a second contiguous magnetic alloy layers: said first magnetic alloy layer comprising a first magnetic alloy material having perpendicular magnetic anisotropy, a high coercive force, a high remnant magnetic flux density and a small anisotropy dispersion angle; said second magnetic layer comprising a second magnetic amorphous alloy of a rare earth metal--3d transition metal positioned on said first magnetic layer, said second magnetic layer having a lower coercive force and higher Curie temperature than said first magnetic layer, said first and second alloys being different alloys and one of them containing one constituent element not present in said other alloy; and a protective layer prepared from a transparent nonmagnetic material on said second magnetic layer.
Claim 6
Dependent Claim
122 words
A recording medium comprising a first and a second contiguous magnetic alloy layers: said first magnetic alloy layer comprising a first magnetic alloy material having perpendicular magnetic anisotropy, a high coercive force, a high remnant magnetic flux density and a small anisotropy dispersion angle; said second magnetic layer comprising a second magnetic amorphous alloy of a rare earth metal--3d transition metal positioned on said first magnetic layer, said second magnetic layer having a lower coercive force and higher Curie temperature than said first magnetic layer, said first and second alloys being different alloys and one of them containing one constituent element not present in said other alloy; and a protective layer prepared from a transparent nonmagnetic material on said second magnetic layer.
Claim 7
Dependent Claim
24 words
The recording medium of claim 4, wherein said first magnetic alloy layer is an amorphous alloy of a rare earth metal 3-d transition metal.
Claim 8
Dependent Claim
15 words
The recording medium of claim 4 or 5, wherein said second magnetic layer comprises Gd-Fe.
Claim 9
Dependent Claim
14 words
The recording medium according to claim 6, wherein the first magnetic layer comprises Tb-Fe.
Claim 10
Dependent Claim
13 words
The recording medium of claim 6, wherein the first magnetic layer comprises Dy-Fe.
Claim 11
Dependent Claim
14 words
The recording medium according to claim 4, wherein the first magnetic layer comprises Tb-Fe.
Claim 12
Dependent Claim
13 words
The recording medium of claim 8, wherein the first magnetic layer comprises Dy-Fe.
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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) | 1988-05-20 | 1988-11-19 | 1989-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-20 | 1992-11-19 | 1993-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-20 | 1996-11-19 | 1997-05-21 | $7700.00 | Window Closed / Lapsed |