Patent US1281163A successfully refreshed from Google Patents.
US3647736A
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Hydrophilic contact lens material
Assignee: Kontur Kontact Lens Co Inc
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Filing: 1970-05-25
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Granted: 1972-03-07
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Expires: 1990-05-25
Abstract
Abstract A HYDROGEL OF A HYDROPHILIC POLYMER FORMED FROM A MAJOR PROPORTION OF A HYDROXYALKYL METHACRYLATE AND A MINOR PORTION OF A POLYALKENE LACTAM, ITS PREPARATION AND USE AS A SOFT CORNEAL CONTACT LENS.
Inventors
- 👤 David G Ewell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:39
CPC Classifications
G; G02; G02B; G02B1/00; G02B1/04; G02B1/041; G02B1/043; C; C08; C08F; C08F271/00; C08F271/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-07 | 1975-09-06 | 1976-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-07 | 1979-09-06 | 1980-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-07 | 1983-09-06 | 1984-03-07 | $7700.00 | Window Closed / Lapsed |