US3556662A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for determining birefringence
Assignee: United States Department of the Navy
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Filing: 1968-05-03
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Granted: 1971-01-19
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Expires: 1988-05-03
Abstract
Abstract A DEVICE FOR ELECTRICALLY AND DIRECTLY INDICATING THE BIREFRINGENCE OF A TRANSPARENT MATERIAL WHICH UTILIZES AN ELECTRO OPTICAL SENSOR HAVING A COMBINATION OF POLARIZERS, BIREFRINGENT PLATES AND PHOTOCELLS TO PRODUCE VOLTAGES FUNCTIONALLY DEPENDENT UPON THE BIREFRINGENCE OF THE TRANSPARENT MATERIAL. DIFFERENCE AMPLIFIERS AND A CATHODE RAY TUBE OR SERVO SYSTEM ANALYZE THE PHOTOCELL PRODUCED VOLTAGES TO GIVE A DIRECT INDICATION OF THE BIREFRINGENCE OF THE TEST MATERIAL.
Inventors
- 👤 Harold Levenstein
- 👤 Albert Goldstein
- 👤 Audrey J Hebling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:37
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/21; G01N21/23
Claims Analysis
Total Claims: 0
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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) | 1974-01-18 | 1974-07-20 | 1975-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-18 | 1978-07-20 | 1979-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-18 | 1982-07-20 | 1983-01-19 | $7700.00 | Window Closed / Lapsed |