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Patent US2906171A successfully refreshed from Google Patents.
US2906171A
Expired / Lapsed
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Varifocal lens system
Assignee: Individual
•
Filing: 1955-12-20
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Granted: 1959-09-29
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Expires: 1975-12-20
Abstract
No abstract record available.
Inventors
- 👤 Bergstein Leonard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:02
CPC Classifications
G; G02; G02B; G02B15/00; G02B15/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2159394A
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US2165341A
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US2179850A
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GB536706A
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US2454686A
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US2566485A
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US2704487A
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US2718817A
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FR1081948A
Cited
US2778272A
Cited
US2782684A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-09-28 | 1963-03-30 | 1963-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-09-28 | 1967-03-30 | 1967-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-09-28 | 1971-03-30 | 1971-09-29 | $7700.00 | Window Closed / Lapsed |