US3488111A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrophilic hydrogel corneal contact lens with hard central insert
Assignee: National Patent Development Corp
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Filing: 1967-03-16
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Granted: 1970-01-06
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Expires: 1987-03-16
Abstract
No abstract record available.
Inventors
- 👤 Allan A Isen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:34
CPC Classifications
G; G02; G02C; G02C7/00; G02C7/02; G02C7/04; G02C7/049; G02C2202/00; G02C2202/16
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-01-05 | 1973-07-07 | 1974-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-01-05 | 1977-07-07 | 1978-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-01-05 | 1981-07-07 | 1982-01-06 | $7700.00 | Window Closed / Lapsed |