US3558221A
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Pink-pass filter means for continuously adjusting the spectral content of a heat radiating object
Assignee: United States Department of the Navy
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Filing: 1968-11-18
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Granted: 1971-01-26
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Expires: 1988-11-18
Abstract
Abstract A VARIABLE APERTURE FILTER HAVING A PAIR OF PINK-PASS FILTERS MECHANICALLY SUPPORTED ON A MEANS TO BE ADJUSTABLY CONTROLLED TO ADVANCE AND RETRACT THE FILTERS OVER THE APERTURE IN A LIGHT PATH OF INFRARED RADIATION TO ADJUSTABLY CONTROL THE BALANCE OF YELLOW AND PINK RADIATION FROM AN INFRARED TARGET RADIATION SOURCE TO SUPPRESS OR MINIMIZE BACKGROUND AND REFLECTED RADIATION AND PASS PINK TARGET RADIATION.
Inventors
- 👤 Donald A Jessup
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:26
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/008; G01; G01S; G01S3/00; G01S3/78; G01S3/781; G02B26/00; G02B26/007
Claims Analysis
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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) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |