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Patent US2643575A successfully refreshed from Google Patents.
US2643575A
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Alignment target for testing eyes
Assignee: Individual
•
Filing: 1947-08-07
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Granted: 1953-06-30
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Expires: 1967-08-07
Abstract
No abstract record available.
Inventors
- 👤 Richards John Mark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:45
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1650768A
Cited
US1946925A
Cited
US1944871A
Cited
US2196904A
Cited
US2238207A
Cited
US2418939A
Cited
US2376554A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-06-29 | 1956-12-29 | 1957-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-06-29 | 1960-12-29 | 1961-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-06-29 | 1964-12-29 | 1965-06-30 | $7700.00 | Window Closed / Lapsed |