US3667949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Imagewise photochromic process utilizing spiropyran compounds and halogenated hydrocarbon photoactivators
Assignee: Canon Inc
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Filing: 1969-03-06
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Granted: 1972-06-06
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Expires: 1989-03-06
Abstract
Abstract A STABLE COLORED IMAGE IS OBTAINED BY USING A SPIROPYRAN COMPOUND AND AN IONIC COMPOUN D IN A COEXISTENT STATE, APPLYING IMAGE-WISE RADIATION THERETO. THE COLORED STATE CAN BE ELIMINATED BY NEUTRALIZING THE IONIC COMPOUND. THUS, THE PHOTOCHROMIC IMAGE FORMATION CAN BE REPEATEDLY EFFECTED.
Inventors
- 👤 Eiichi Inoue
- 👤 Isamu Shimizu
- 👤 Hajime Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:13
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/685; G03C1/675; Y; Y10; Y10S; Y10S430/00; Y10S430/163
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) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |