US3744870A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical filter comprising a substrate of metal fluoride having deposited thereon a film of strontium or barium fluoride
Assignee: Panasonic Holdings Corp
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Filing: 1971-05-28
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Granted: 1973-07-10
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Expires: 1991-05-28
Abstract
Abstract An optical filter for selectively transmitting the ultraviolet rays of a predetermined spectral range including 1,300 A. triplet of atomic oxygen, which filter comprises an about 2 mm thick substrate composed of a metal fluoride, such as CaF2, LiF or MgF2 and a thin film having a thickness of 420 to 1,000 A. deposited thereon and composed of SrF2 or BaF2. By fabricating the thin film in such extremely thin lamina form, it is possible to completely isolate the ultraviolet rays of the predetermined range from the Lyman alpha radiation of atomic hydrogen even when the filter is subject to relatively large changes in the ambient temperature.
Inventors
- 👤 T Tomiki
- 👤 T Miyata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:54
CPC Classifications
C; C10; C10M; C10M173/00; G; G02; G02B; G02B5/00; G02B5/20; G02B5/208
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
20 words
An optical filter according to claim 1, wherein said thin film has a thickness of from 420 to 500 A.
Claim 2
Dependent Claim
16 words
The method of claim 2 wherein the substrate has a thickness of 0.5 to 5 mm.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |