Patent US3542535A successfully refreshed from Google Patents.
US3542535A
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US
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Multi-focal lens with index gradient
Assignee: Bausch and Lomb Inc
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Filing: 1967-11-15
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Granted: 1970-11-24
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Expires: 1987-11-15
Abstract
No abstract record available.
Inventors
- 👤 Joseph R Hensler
- 👤 Charles H Rosenbauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:27
CPC Classifications
C; C03; C03B; C03B23/00; C03B23/20; C03B23/22; C03C; C03C21/00; G; G02; G02C; G02C7/00; G02C7/02; G02C7/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USRE20059E
Cited
US1221967A
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US1588783A
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US1996442A
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US2649387A
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US2701215A
Cited
US2963823A
Cited
US3320114A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-11-23 | 1974-05-25 | 1974-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-11-23 | 1978-05-25 | 1978-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-11-23 | 1982-05-25 | 1982-11-24 | $7700.00 | Window Closed / Lapsed |