US3720143A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mask for selectively exposing photo-resist to light
Assignee: Hitachi Ltd
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Filing: 1971-02-02
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Granted: 1973-03-13
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Expires: 1991-02-02
Abstract
Abstract A mask for photoengraving and its method of manufacture, which mask comprises a transparent glass substrate, an aluminum layer formed on the substrate with a predetermined pattern and an anodized aluminum oxide layer formed on the aluminum layer, the aluminum oxide layer may include a substance which does not reflect light, such as ultraviolet rays.
Inventors
- 👤 T Hashimoto
- 👤 I Tanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:48
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/38; G03F1/46; G03F1/54
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
44 words
A mask for photoengraving comprising a transparent substrate, a nd a film containing porous aluminum oxide and silver sulfide provided in the pores, said film being formed on a surface portion of said transparent substrate with a thickness of not less than 500 angstroms.
Claim 2
Dependent Claim
44 words
A mask for photoengraving comprising a transparent substrate, a nd a film containing porous aluminum oxide and silver sulfide provided in the pores, said film being formed on a surface portion of said transparent substrate with a thickness of not less than 500 angstroms.
Claim 3
Dependent Claim
57 words
A mask for photoengraving comprising a transparent substrate, a first film consisting essentially of aluminum formed on a surface portion of said transparent substrate, and a second film containing porous aluminum oxide and silver sulfide provided in the pores, said second film being formed on said first film with a thickness of not less than 500 angstroms.
Claim 4
Dependent Claim
57 words
A mask for photoengraving comprising a transparent substrate, a first film consisting essentially of aluminum formed on a surface portion of said transparent substrate, and a second film containing porous aluminum oxide and silver sulfide provided in the pores, said second film being formed on said first film with a thickness of not less than 500 angstroms.
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) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |