US3733217A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making interference filters
Assignee: Howard Grubb Parsons & Co
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Filing: 1971-07-28
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Granted: 1973-05-15
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Expires: 1991-07-28
Abstract
Abstract A METHOD OF MAKING AN INTERFERENCE MULTI-LAYER FILTER FORUSE WITH INFRA-RED RADIATION, WHICH INCLUDES THE STEPS OF DEPOSITING IN VACUO ON A SUBSTRATE, SELECTED FROM THE GROUP COMPRISING GERMANIUM, SILICON AND CRYSTAL QUARTZ, ALTERNATE LAYERS OF CAESIUM IODIDE AND A MATERIAL OF DIFFERENT REFRACTIVE INDEX SELECTED FROM THE GROUP COMPRISING GERMANIUM, SILICON, TELLURIUM AND LEAD TELLURIDE. THE SUBSTRATE IS HEATED TO A TEMPERATURE IN THE RANGE OF 130-230*C. AND AFTER DEPOSITION OF THE ALTERNATE LAYERS THE SUBSTRATE IS ALLOWED TO COOL DOWN TO A TEMPERATURE OF 20*C. AT A RATE NOT EXCEEDING 1*C. PER MINUTE BEFORE ADMITTING AIR AT AMBIENT TEMPERATURE INTO THE VACUUM CHAMBER.
Inventors
- 👤 J Seeley
- 👤 S Smith
- 👤 F Ritchie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:45
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/20; G02B5/28; G02B5/281; G02B5/285; Y; Y10; Y10S; Y10S148/00; Y10S148/064; Y10S148/067; Y10S148/072; Y10S148/15; Y10S148/169; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31652; Y10T428/31667
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-14 | 1976-11-13 | 1977-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-14 | 1980-11-13 | 1981-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-14 | 1984-11-13 | 1985-05-15 | $7700.00 | Window Closed / Lapsed |