US4816840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical recording medium and method for producing the same
Assignee: Canon Inc
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Filing: 1987-07-31
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Granted: 1989-03-28
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Expires: 2007-07-31
Abstract
Abstract An optical recording medium, having a substrate and a thin film containing a fluoride compound and a substance capable of undergoing an optical change through absorption of electromagnetic radiation (a film sensitive to electromagnetic radiation).
Inventors
- 👤 Yoichi Osato
- 👤 Ichiro Saito
- 👤 Yoshio Takasu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:00
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/242; G11B7/243; G11B7/251; G11B7/26; G11B2007/24302; G11B2007/24312; G11B2007/24314; G11B2007/24316; G11B2007/24318; G11B2007/24326; G11B2007/24328; Y; Y10; Y10S; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
139 words
A method for preparing a laser beam-readable optical recording medium comprising: providing a medium including a substrate having thereon a thin film containing a fluoride compound and a substance capable of undergoing a change in reflectivity through the absorption of electromagnetic radiation; and irradiating said medium with an electromagnetic radiation beam to form on said thin film first portions having higher reflectivity than second portions of said medium surrounding said first portions, but not causing a portion of said film to become lower than its surroundings or creating a portion of said film wherein there is an opening extending through said film, wherein in said first portions having higher reflectivity the fraction of total radiant flux incident thereupon which is reflected is greater than the fraction of total radiant flux incident upon said second portions medium which is reflected.
Claim 2
Independent Claim
139 words
A method for preparing a laser beam-readable optical recording medium comprising: providing a medium including a substrate having thereon a thin film containing a fluoride compound and a substance capable of undergoing a change in reflectivity through the absorption of electromagnetic radiation; and irradiating said medium with an electromagnetic radiation beam to form on said thin film first portions having higher reflectivity than second portions of said medium surrounding said first portions, but not causing a portion of said film to become lower than its surroundings or creating a portion of said film wherein there is an opening extending through said film, wherein in said first portions having higher reflectivity the fraction of total radiant flux incident thereupon which is reflected is greater than the fraction of total radiant flux incident upon said second portions medium which is reflected.
Claim 3
Dependent Claim
46 words
The method according to claim 1, wherein said fluoride compound is at least one compound selected from the group consisting of BiF 3 , MgF 2 , PbF 2 , LiF, CeF 3 , AgF, CaF 2 , CrF 2 , CrF 3 and carbon fluoride.
Claim 4
Dependent Claim
16 words
The method according to claim 1, wherein said fluoride compound is BiFx 1 (0<x 1 ≦3).
Claim 5
Dependent Claim
16 words
The method according to claim 1, wherein said fluoride compound is PbFx 2 (0<x 2 ≦2).
Claim 6
Dependent Claim
32 words
The method according to claim 1, wherein the substance capable of undergoing a change in reflectivity through absorption of electromagnetic radiation is a substance which undergoes an optical change by thermal action.
Claim 7
Dependent Claim
40 words
The method according to claim 5, wherein the substance capable of undergoing change in reflectivity through absorption of electromagnetic radiation is at least one substance selected from the group consisting of Te, Pb, Au, Sn, As, Bi, In and carbon.
Claim 8
Dependent Claim
19 words
The method according to claim 1, wherein said thin film has a thickness of 300 Å to 5000 Å.
Claim 9
Dependent Claim
16 words
The method according to claim 1, wherein a protective layer is provided on said thin film.
Claim 10
Dependent Claim
17 words
The method according to claim 1, wherein a reflection preventive film is provided on said thin film.
Claim 11
Dependent Claim
19 words
The method according to claim 1, wherein a reflection layer is provided between said substrate and said thin film.
Claim 12
Dependent Claim
24 words
The method according to claim 10, wherein said reflection layer is a vapor deposited layer or a laminated layer of aluminum, silver or chromium.
Claim 13
Dependent Claim
20 words
The method according to claim 1, wherein said substrate is a transparent material having a transmittance of 90% or higher.
Claim 14
Dependent Claim
22 words
The method according to claim 12, wherein the transparent material is glass, polyester, polypropylene, polycarbonate, polyvinyl chloride, polyamide, polystyrene or polymethyl methacrylate.
Claim 15
Dependent Claim
13 words
The method according to claim 1, wherein said substrate is a metal plate.
Claim 16
Dependent Claim
21 words
The method according to claim 1, wherein said electromagnetic radiation is a semiconductor laser, argon gas laser or helium-neon gas laser.
Claim 17
Dependent Claim
37 words
The method according to claim 1, wherein said thin film is a coated film comprising a substance capable of undergoing a change in reflectivity through absorption of electromagnetic radiation contained in a matrix of a fluoride compound.
Claim 18
Dependent Claim
33 words
The method according to claim 1, wherein the substance capable of undergoing a change in reflectivity through absorption of electromagnetic radiation is contained in an amount ranging from 20 to 70 mole %.
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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) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |