Patent US3114233A successfully refreshed from Google Patents.
Patent US3787378A successfully refreshed from Google Patents.
US3787378A
Expired / Lapsed
US
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Optical contact lenses and related devices
Assignee: Hydrophilics International Inc
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Filing: 1973-01-24
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Granted: 1974-01-22
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Expires: 1993-01-24
Abstract
Abstract A COPOLYMER HAVNG HYDROPHILIC SURFACES FORMED THROUGH THE BULK COPOLYMERIZATION OF METHYL METHACRYLATE AND ACRYLIC ACID, IN PARTICULAR RANGES, FOLLOWED BY A TREATMENT OF THE FORMED COPOLYMER WITH A MILD. BASIC MATERIAL, SUCH AS AMMONIUM HYDROXIDE, IN ORDER TO NEUTRALIZE THE ACID GROUPS PRESENT. THE DEPTH TO PENETRATION OF THE BASIC MATERIAL DETERMINES THE DEGREE TO WHICH THE MATERIAL IS HYDROPHILIC. A THERAPEUTIC AGENT MAY BE INCORPORATED INTO THE COPOLYMER AFTER TREATMENT.
Inventors
- 👤 I Blank
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:54
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/10; C08F220/12; C08F220/14; B; B29; B29D; B29D11/00; G; G02; G02B; G02B1/00; G02B1/04; G02B1/041; G02B1/043; Y; Y10; Y10S; Y10S526/00; Y10S526/93; Y10S526/936
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |