Patent US2803993A successfully refreshed from Google Patents.
US2803993A
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Projection apparatus
Assignee: American Optical Corp
•
Filing: 1953-09-21
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Granted: 1957-08-27
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Expires: 1973-09-21
Abstract
No abstract record available.
Inventors
- 👤 John F Herrmann
- 👤 Henry T Wilton
- 👤 Dominic A Sanni
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:51
CPC Classifications
G; G03; G03B; G03B23/00; G03B23/08; G03B23/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1679399A
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US1738762A
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US1704814A
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US2126474A
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US2231765A
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US2330709A
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US2407339A
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GB598483A
Cited
GB681262A
Cited
US2595978A
Cited
US2724990A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-08-26 | 1961-02-25 | 1961-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-08-26 | 1965-02-25 | 1965-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-08-26 | 1969-02-25 | 1969-08-27 | $7700.00 | Window Closed / Lapsed |