US4802160A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical disk substrate
Assignee: Fujifilm Holdings Corp
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Filing: 1987-10-05
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Granted: 1989-01-31
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Expires: 2007-10-05
Abstract
Abstract An optical disk substrate has a surface on which a pre-groove for light beam tracking is formed. Non-pregrooved regions on the substrate surface on which the pregroove is formed are subjected to surface roughing processing to improve adhesion of the substrate surface in the non-pregrooved regions to a film which is to be overlaid on the optical disk substrate.
Inventors
- 👤 Takashi Yamada
- 👤 Masaaki Nomura
- 👤 Ryoichi Yamamoto
- 👤 Akira Nahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:30
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
72 words
An optical disk substrate having a surface on which an annular pre-groove is disposed for light beam tracking and further surfaces on which first and second annular non-pre-grooved regions are respectively disposed outside and inside the annular pre-groove wherein at least one of said first and second annular non-pre-grooved regions extends to the pre-groove and wherein the entirety of the first and second annular non-pre-grooved regions are subjected to surface roughing processing.
Claim 2
Dependent Claim
72 words
An optical disk substrate having a surface on which an annular pre-groove is disposed for light beam tracking and further surfaces on which first and second annular non-pre-grooved regions are respectively disposed outside and inside the annular pre-groove wherein at least one of said first and second annular non-pre-grooved regions extends to the pre-groove and wherein the entirety of the first and second annular non-pre-grooved regions are subjected to surface roughing processing.
Claim 3
Dependent Claim
38 words
An optical disk substrate as defined in claim 1 wherein minute protrusions or recesses having heights or depths within the range of approximately 0.05μ to approximately 5μ are formed by said surfaces roughing processing in said non-pre-grooved regions.
Claim 4
Dependent Claim
30 words
An optical disk substrate as defined in claim 1 wherein both said first and second annular non-pre-grooved regions respectively extend to the outer and inner circumferential edges of the pre-groove.
References Cited (Backward Citations)
US4720826A
Cited
US4710913A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-01-31 | 1992-08-01 | 1993-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-31 | 1996-08-01 | 1997-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-31 | 2000-08-01 | 2001-01-31 | $7700.00 | Window Closed / Lapsed |