US3734754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermally darkening photochromic glass
Assignee: Corning Glass Works
•
Filing: 1970-08-19
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Granted: 1973-05-22
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Expires: 1990-08-19
Abstract
Abstract THIS INVENTION RELATES TO ARTICLES COMPRISING LANTHANUM BORATE GLASSES WHICH EXHIBIT UNUSUAL PHOTOCHROMIC BEHAVIOR. THIS PHOTOCHROMISM IS CHARACTERIZED BY A DARKENED THERMALLY STABLE STATE AND BY BLEACHING TO A CLEAR STATE IN RESPONSE TO ACTINIC RADIATION. THESE GLASSES ARE FURTHER CHARACTERIZED BY THE FACT THAT THEY BECOME COLORLESS ABOVE A CERTAIN HIGH TEMPERATURE AND COLORED AGAIN WHEN THE TEMPERATURE IS LOWERED BELOW A CERTAIN CRITICAL VALUE.
Inventors
- 👤 L Randall
- 👤 T Seward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:14
CPC Classifications
C; C03; C03C; C03C4/00; C03C4/04; C03C4/06; Y; Y10; Y10S; Y10S501/00; Y10S501/90
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) | 1976-05-21 | 1976-11-20 | 1977-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-21 | 1980-11-20 | 1981-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-21 | 1984-11-20 | 1985-05-22 | $7700.00 | Window Closed / Lapsed |