Patent US3473503A successfully refreshed from Google Patents.
US3370902A
Expired / Lapsed
US
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Self-attenuating variable density light filter lens and compounds for making
Assignee: Individual
•
Filing: 1963-07-16
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Granted: 1968-02-27
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Expires: 1983-07-16
Abstract
Abstract A self-attenuating variable density light filtering compound for use with flash protection goggles comprises a triphenylmethane dye and a bisulphate activated proteolytic enzyme in a carrier solution. The die may be Malachite Green, Acid Fuchsin or Rosanaline Red. The enzyme may be, e.g. papain, ficin, or pepsin in sodium bisulphite solution. This compound does not revert to a colourless state in the presence of ultra-violet light. The compound may be mixed with polyvinyl alcohol diluted with methyl alcohol, and with a gelling agent, e.g. Guar gum, and mounted as a paste on, or as a solution between, glass plates.
Inventors
- 👤 Allinikov Sidney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:33
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/20; G02B5/22; G02B5/23; G02C; G02C7/00; G02C7/10; G02C7/102; G02C7/108; G03; G03C; G03C1/00; G03C1/72; G03C1/73; G03C1/731
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1845835A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-02-26 | 1971-08-28 | 1972-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-02-26 | 1975-08-28 | 1976-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-02-26 | 1979-08-28 | 1980-02-27 | $7700.00 | Window Closed / Lapsed |