US4946730A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and photomask for manufacturing optical memory element
Assignee: Sharp Corp
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Filing: 1988-12-01
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Granted: 1990-08-07
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Expires: 2008-12-01
Abstract
Abstract A method of and a photomask for manufacturing an optical memory element. The manufacturing method includes the steps of: subjecting a positive type photoresist coated on a glass substrate to exposure, by using the photomask capable of irradiating light onto a portion of the photoresist other than the remaining portion, for forming pits on the glass substrate such that the portion of the photoresist is solubilized against developing solution; developing the photoresist by using the developing solution so as to remove the portion of the photoresist; and etching the glass substrate so as to directly form, as convex portions, the pits on a surface of the glass substrate.
Inventors
- 👤 Tetsuya Inui
- 👤 Junji Hirokane
- 👤 Akira Shibata
- 👤 Yoshiyuki Nagahara
- 👤 Kenji Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:22
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B7/261; Y; Y10; Y10S; Y10S428/00; Y10S428/913
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
78 words
An optical memory element for recording, reproducing or erasing information by using light, comprising: a substrate having a track formed thereon; and a recording medium which is provided on the substrate; wherein a first plurality of raised portions are so provided as to be staggered with respect to a center line of the track and wherein a second plurality of raised portions are disposed on the center line, the raised portions being formed convexly relative to the substrate.
Claim 2
Dependent Claim
78 words
An optical memory element for recording, reproducing or erasing information by using light, comprising: a substrate having a track formed thereon; and a recording medium which is provided on the substrate; wherein a first plurality of raised portions are so provided as to be staggered with respect to a center line of the track and wherein a second plurality of raised portions are disposed on the center line, the raised portions being formed convexly relative to the substrate.
Claim 3
Dependent Claim
16 words
An optical memory element as claimed in claim 6, wherein the substrate is made of glass.
Claim 4
Dependent Claim
17 words
An optical memory element as claimed in claim 1, wherein the recording medium is made magnetooptical material.
References Cited (Backward Citations)
US4223347A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-06 | 1994-02-05 | 1994-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-06 | 1998-02-05 | 1998-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-06 | 2002-02-05 | 2002-08-07 | $7700.00 | Window Closed / Lapsed |