US5128922A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical disk with glass substrate and method of producing same
Assignee: Sharp Corp
•
Filing: 1991-04-18
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Granted: 1992-07-07
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Expires: 2011-04-18
Abstract
Abstract An optical disk with a substrate made of glass at least partially has its inner and outer peripheral surfaces polished to surface roughness of 5 μm or less so as to reduce the amount of glass powder generated from these surfaces and to thereby improve the yield.
Inventors
- 👤 Tetsuya Inui
- 👤 Junji Hirokane
- 👤 Akira Shibata
- 👤 Yoshiyuki Nagahara
- 👤 Kenji Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:44
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
101 words
An optical disc, comprising: a disk shaped substrate comprised of glass, the disc having a circular outer peripheral surface having a beveled edge, a circular hole centrally located in the disc, the hole being surrounded by an inner circular peripheral surface having a beveled edge, a first planar surface extending between the circular outer peripheral surface and a circular inner peripheral surface around the hole and a second planar surface opposite the first planar surface wherein the beveled edge of the outer peripheral surface and the inner peripheral surface each has a ground glass surface roughness of 5 μm or less.
Claim 2
Dependent Claim
101 words
An optical disc, comprising: a disk shaped substrate comprised of glass, the disc having a circular outer peripheral surface having a beveled edge, a circular hole centrally located in the disc, the hole being surrounded by an inner circular peripheral surface having a beveled edge, a first planar surface extending between the circular outer peripheral surface and a circular inner peripheral surface around the hole and a second planar surface opposite the first planar surface wherein the beveled edge of the outer peripheral surface and the inner peripheral surface each has a ground glass surface roughness of 5 μm or less.
Claim 3
Independent Claim
145 words
A method of producing an optical disc, comprising the steps of: providing a disc shaped substrate comprised of glass, the disc having a circular outer peripheral surface, a circular hole centrally located in the disc, the hole being surrounded by an inner peripheral surface, a first planar surface extending between the circular outer peripheral surface and the inner peripheral surface around the hole and a second planar surface, opposite the first planar surface; forming a beveled edge on the outer and the inner peripheral surfaces; grinding the beveled edge on the inner and outer peripheral surfaces until each has a ground glass surface roughness of 5 μm or less; coating the first planar surface with a photoresist to provide a photoresist layer; contacting the photoresist layer with a photomask having openings therein; and exposing the photoresist layer to light through the openings of the photomask.
Claim 4
Independent Claim
145 words
A method of producing an optical disc, comprising the steps of: providing a disc shaped substrate comprised of glass, the disc having a circular outer peripheral surface, a circular hole centrally located in the disc, the hole being surrounded by an inner peripheral surface, a first planar surface extending between the circular outer peripheral surface and the inner peripheral surface around the hole and a second planar surface, opposite the first planar surface; forming a beveled edge on the outer and the inner peripheral surfaces; grinding the beveled edge on the inner and outer peripheral surfaces until each has a ground glass surface roughness of 5 μm or less; coating the first planar surface with a photoresist to provide a photoresist layer; contacting the photoresist layer with a photomask having openings therein; and exposing the photoresist layer to light through the openings of the photomask.
References Cited (Backward Citations)
US3673746A
Cited
US4546464A
Cited
JPS60195751A
Cited
JPS60197960A
Cited
US4678547A
Cited
US4802160A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-07 | 1996-01-06 | 1996-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-07 | 2000-01-06 | 2000-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-07 | 2004-01-06 | 2004-07-07 | $7700.00 | Window Closed / Lapsed |