US4764441A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photo-mask for production of substrate for optical memory element
Assignee: Sharp Corp
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Filing: 1986-11-12
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Granted: 1988-08-16
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Expires: 2006-11-12
Abstract
Abstract A photo-mask which is used for the production of a substrate for an optical memory element includes a reflective film formed over an ultraviolet non-transmissive film on a substrate. Alternatively, a multi-layer dielectric film which is not transmissive to light of wavelength about 400 nm but transmissive to light of wavelength about 450 nm is formed on a substrate.
Inventors
- 👤 Kenji Ohta
- 👤 Junji Hirokane
- 👤 Tetsuya Inui
- 👤 Akira Takahashi
- 👤 Hiroyuki Katayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:59
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/54; G03F1/58; G03F1/38; G03F1/50
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
25 words
A photo-mask comprising a mask substrate, an ultraviolet non-transmissive film formed on said mask substrate, and a reflective film formed on said ultraviolet non-transmissive film.
Claim 2
Dependent Claim
25 words
A photo-mask comprising a mask substrate, an ultraviolet non-transmissive film formed on said mask substrate, and a reflective film formed on said ultraviolet non-transmissive film.
Claim 3
Dependent Claim
16 words
The photo-mask of claim 1 wherein said reflective film comprises one or more dielectric film layers.
Claim 4
Dependent Claim
19 words
The photo-mask of claim 1 which is used for the production of a substrate for an optical memory element.
Claim 5
Dependent Claim
12 words
The photo-mask of claim 1 wherein said ultraviolet non-transmissive film comprises Cr.
Claim 6
Dependent Claim
12 words
The photo-mask of claim 1 wherein said ultraviolet non-transmissive film comprises Ta.
Claim 7
Dependent Claim
36 words
A photo-mask comprising a mask substrate and a multi-layer dielectric film over said mask substrate, said dielectric film being non-transmissive to light of wavelength about 400 nm and transmissive to light of wavelength about 450 nm.
Claim 8
Dependent Claim
36 words
A photo-mask comprising a mask substrate and a multi-layer dielectric film over said mask substrate, said dielectric film being non-transmissive to light of wavelength about 400 nm and transmissive to light of wavelength about 450 nm.
Claim 9
Dependent Claim
16 words
The photo-mask of claim 6 which is used for the production of an optical memory element.
Claim 10
Dependent Claim
25 words
The photo-mask of claim 6 wherein said mask substrate is of a material selected from a group consisting of glass, acryl resins and epoxy resins.
Claim 11
Dependent Claim
14 words
The photo-mask of claim 6 wherein said multi-layer dielectric film comprises SiO 2 .
Claim 12
Dependent Claim
12 words
The photo-mask of claim 6 wherein said multi-layer dielectric film comprises CeO.
Claim 13
Dependent Claim
14 words
The photo-mask of claim 6 wherein said multi-layer dielectric film comprises TiO 2 .
Claim 14
Dependent Claim
16 words
The photo-mask of claim 6 wherein said multi-layer dielectric film comprises Al 2 O 3 .
Claim 15
Dependent Claim
12 words
The photo-mask of claim 6 wherein said multi-layer dielectric film comprises MgF.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-16 | 1992-02-15 | 1992-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-16 | 2000-02-15 | 2000-08-16 | $7700.00 | Window Closed / Lapsed |