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Patent US2493200A successfully refreshed from Google Patents.
US2493200A
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US
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Variable polarizing color filter
Assignee: Polaroid Corp
•
Filing: 1946-05-31
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Granted: 1950-01-03
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Expires: 1966-05-31
Abstract
No abstract record available.
Inventors
- 👤 Edwin H Land
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:23
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/28; G02B27/288; G02B5/00; G02B5/30; G02B5/3025; G02B5/3033; G02F; G02F1/00; G02F1/01; G02F1/23
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2118160A
Cited
US2010307A
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US2109540A
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US2184999A
Cited
US2350892A
Cited
US2263684A
Cited
US2298059A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-01-02 | 1953-07-04 | 1954-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-01-02 | 1957-07-04 | 1958-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-01-02 | 1961-07-04 | 1962-01-03 | $7700.00 | Window Closed / Lapsed |