Patent US3649549A successfully refreshed from Google Patents.
US3649549A
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Structures for photochromic compounds
Assignee: Raytheon Co
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Filing: 1967-10-19
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Granted: 1972-03-14
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Expires: 1987-10-19
Abstract
Abstract THE DISCLOSURE HEREIN RELATES TO REVERSIBLE PHOTOTROPIC SYSTEMS, COMPOUNDS AND COMPOSITIONS AND THE DISCOVERY OF PHOTOCHROMIC STRUCTURES WHICH REGULARLY UNDERGO REVERSIBLE PHOTOTROPISM AS PHOTO-INDUCED REVERSIBLE COLOR CHANGE IN WATER CONTAINING SUBSTRATES INCLUDING PARTICULARLY THE CONTROL OF THEIR BACK REACTIONS AND THE METHOD OF USE THEREOF BY PROVIDING A MULTIPLE COLOR AND COLOR CHANGE INDICATOR AND/OR LIGHT FILTERS.
Inventors
- 👤 John D Margerum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:58
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/72; G03C1/73; H; H01; H01S; H01S3/00; H01S3/10; H01S3/11; H01S3/1123; H01S3/113
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) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |