Patent US4809022A successfully refreshed from Google Patents.
US4809022A
Expired / Lapsed
US
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Direct read after write optical storage medium
Assignee: Optical Disc Corp
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Filing: 1983-06-27
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Granted: 1989-02-28
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Expires: 2003-06-27
Abstract
Abstract An optical storage media. The DRAW recording medium of the present invention consists of a three layer structure: a transparent substrate; a uniform layer of a dielectric light-responsive material having a threshold energy level at which a physical change in the material occurs; and a highly electrically conductive and highly reflective overcoating on the opposite side of the light-responsive layer from the substrate. The invention provides a DRAW recording medium which is capable of recording information immediately readable in accordance with the International Electrotechnical Commission optical disc standard for videodiscs.
Inventors
- 👤 Richard L. Wilkinson
- 👤 John S. Winslow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:58
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/004; G11B7/005; G11B7/0051; Y; Y10; Y10S; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
127 words
A DRAW disc compatible with the IEC standard for optical videodiscs, comprising: a transparent substrate; a first layer of delectric material in the range of 2300 Å to 2500 Å in thickness on one surface of said substrate, said material having an absorption coefficient for light of a wavelength of 4880 Å of between 2×10 -4 /Å and 6×10 -4 /Å, said material having a threshold energy for light of a wavelength of 4880 Å above which it decomposes into primarily gasseous products; and an essentially flat reflective layer of electrically conductive material in excess of 200 Å in thickness on the opposite side of said first layer from said substrate, said disc being between 75% and 85% reflective of light having a wavelength of 6328 Å.
Claim 2
Dependent Claim
127 words
A DRAW disc compatible with the IEC standard for optical videodiscs, comprising: a transparent substrate; a first layer of delectric material in the range of 2300 Å to 2500 Å in thickness on one surface of said substrate, said material having an absorption coefficient for light of a wavelength of 4880 Å of between 2×10 -4 /Å and 6×10 -4 /Å, said material having a threshold energy for light of a wavelength of 4880 Å above which it decomposes into primarily gasseous products; and an essentially flat reflective layer of electrically conductive material in excess of 200 Å in thickness on the opposite side of said first layer from said substrate, said disc being between 75% and 85% reflective of light having a wavelength of 6328 Å.
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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) | 1992-02-28 | 1992-08-29 | 1993-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-28 | 1996-08-29 | 1997-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-28 | 2000-08-29 | 2001-02-28 | $7700.00 | Window Closed / Lapsed |