US2440070A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical filter and method of manufacture
Assignee: POLARVID Corp
•
Filing: 1944-10-28
•
Granted: 1948-04-20
•
Expires: 1964-10-28
Abstract
No abstract record available.
Inventors
- 👤 Elkan R Blout
- 👤 Ralph M Gofstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:44
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/76; G03C1/815; G03C1/8155; G02; G02B; G02B5/00; G02B5/20; G02B5/22; G02B5/223
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2340882A
Cited
US2298733A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-04-20 | 1951-10-20 | 1952-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-04-20 | 1955-10-20 | 1956-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-04-20 | 1959-10-20 | 1960-04-20 | $7700.00 | Window Closed / Lapsed |