US2520635A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical system
Assignee: Polaroid Corp
•
Filing: 1949-03-10
•
Granted: 1950-08-29
•
Expires: 1969-03-10
Abstract
No abstract record available.
Inventors
- 👤 David S Grey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:52
CPC Classifications
G; G02; G02B; G02B17/00; G02B17/08; G02B17/0852; G02B17/0804; G02B17/0808; G02B17/0856; G02B21/00; G02B21/02; G02B21/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1967214A
Cited
US2141884A
Cited
US2198014A
Cited
GB544694A
Cited
US2413286A
Cited
US2403660A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-08-28 | 1954-02-27 | 1954-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-08-28 | 1958-02-27 | 1958-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-08-28 | 1962-02-27 | 1962-08-29 | $7700.00 | Window Closed / Lapsed |