US2638688A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter testing device
Assignee: American Optical Corp
•
Filing: 1948-09-23
•
Granted: 1953-05-19
•
Expires: 1968-09-23
Abstract
No abstract record available.
Inventors
- 👤 Charles L Hazelton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:12
CPC Classifications
G; G09; G09B; G09B25/00; G09B25/02; Y; Y10; Y10S; Y10S116/00; Y10S116/42; Y10S55/00; Y10S55/31; Y10S55/34
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2184433A
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US2228371A
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US2254259A
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US2355858A
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US2346690A
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US2485588A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-05-18 | 1956-11-17 | 1957-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-05-18 | 1960-11-17 | 1961-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-05-18 | 1964-11-17 | 1965-05-19 | $7700.00 | Window Closed / Lapsed |