Patent US2274706A successfully refreshed from Google Patents.
US2274706A
Expired / Lapsed
US
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Process of making a light polarizing medium
Assignee: PPG Industries Inc
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Filing: 1939-04-11
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Granted: 1942-03-03
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Expires: 1959-04-11
Abstract
No abstract record available.
Inventors
- 👤 Laurence A Keim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:48
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/30; G02B5/3025; G02B5/3033
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) | 1945-03-02 | 1945-09-01 | 1946-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1949-03-02 | 1949-09-01 | 1950-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1953-03-02 | 1953-09-01 | 1954-03-03 | $7700.00 | Window Closed / Lapsed |