US4839883A
Expired / Lapsed
US
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Optical information recording medium
Assignee: Panasonic Holdings Corp
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Filing: 1987-06-25
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Granted: 1989-06-13
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Expires: 2007-06-25
Abstract
Abstract There is provided a rewritable tri-layer optical information recording medium of the phase change type having a high sensitivity. In this medium, a reflective layer is formed by a thin film of an Ni-Cr alloy or an Au-Cr alloy.
Inventors
- 👤 Kenichi Nagata
- 👤 Noboru Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:53
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/252; G11B7/258; G11B7/2595; Y; Y10; Y10S; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
97 words
A reversible optical information recording medium comprising: a substrate; an absorptive layer, overlying the substrate, which absorbs a light of a wavelength of an irradiating laser beam for any one of recording, reproducing, and erasing and which may be reversibly switched to a state having different optical properties; a reflective layer, overlying the absorptive layer, for reflecting a considerable portion of the light of an irradiating laser beam; and a spacer layer interposed between said absorptive layer and said reflective layer, wherein said reflective layer comprises a thin film of an Ni-Cr alloy or an Au-Cr alloy.
Claim 2
Dependent Claim
97 words
A reversible optical information recording medium comprising: a substrate; an absorptive layer, overlying the substrate, which absorbs a light of a wavelength of an irradiating laser beam for any one of recording, reproducing, and erasing and which may be reversibly switched to a state having different optical properties; a reflective layer, overlying the absorptive layer, for reflecting a considerable portion of the light of an irradiating laser beam; and a spacer layer interposed between said absorptive layer and said reflective layer, wherein said reflective layer comprises a thin film of an Ni-Cr alloy or an Au-Cr alloy.
Claim 3
Dependent Claim
62 words
A recording medium according to claim 1, wherein said absorptive layer comprises a material which can reversibly cause a phase transition between a crystalline phase and an amorphous phase upon irradiation by a laser beam, and said reflective layer comprises a thin film of an Ni-Cr alloy or an Au-Cr alloy of a thermal diffusivity lower than that of Au or Al.
Claim 4
Dependent Claim
45 words
A recording medium according to claim 1, wherein said reflective layer is composed of an Ni-Cr alloy and when it is assumed that the composition of said alloy is Ni 100-x Cr x , x is set to a value within a range of 10≦x≦90.
Claim 5
Dependent Claim
20 words
A recording medium according to claim 3, wherein said x is set to a value within a range of 20≦x≦80.
Claim 6
Dependent Claim
29 words
A recording medium according to claim 1, wherein a thickness of said thin Ni-Cr alloy film is set to a value within a range of 200 to 600 Å.
Claim 7
Dependent Claim
46 words
A recording medium according to claim 1, wherein said reflective layer is composed of an Au-Cr alloy and when it is assumed that the composition of said alloy is Au 100-y Cr y , said y is set to a value within a range of 2≦y≦30.
Claim 8
Dependent Claim
20 words
A recording medium according to claim 6, wherein said y is set to a value within a range of 10≦y≦20.
Claim 9
Dependent Claim
29 words
A recording medium according to claim 1, wherein a thickness of said thin Au-Cr alloy film is set to a value within a range of 100 to 600 Å.
Claim 10
Dependent Claim
16 words
A recording medium according to claim 2, wherein said reflective layer comprises an Ni-Cr alloy film.
Claim 11
Dependent Claim
32 words
A recording medium as in claim 9 wherein said Ni-Cr alloy film has a composition of Ni 100-x Cr x and x is set to a value in the range of 10≦×≦90.
Claim 12
Dependent Claim
19 words
A recording medium according to claim 10, wherein x is set to a value within a range of 20≦×≦80.
Claim 13
Dependent Claim
21 words
A recording medium according to claim 9, wherein a thickness of said thin Ni-Cr alloy film is 200 to 600 Å.
Claim 14
Dependent Claim
15 words
A recording medium according to claim 2, wherein said reflective layer comprises an Au-Cr alloy.
Claim 15
Dependent Claim
32 words
A recording medium according to claim 13 wherein said Au-Cr alloy film has a composition of Au 100-y Cr y and y is set to a value in the range of 2≦y≦30.
Claim 16
Dependent Claim
19 words
A recording medium according to claim 14, wherein y is set to a value within a range of 10≦y≦20.
Claim 17
Dependent Claim
29 words
A recording medium according to claim 13 wherein a thickness of said thin Au-Cr alloy film is set to a value within a range of 100 to 600 Å.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-12 | 1992-12-12 | 1993-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-12 | 1996-12-12 | 1997-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-12 | 2000-12-12 | 2001-06-13 | $7700.00 | Window Closed / Lapsed |