Patent US4468222A successfully refreshed from Google Patents.
Patent US2187780A successfully refreshed from Google Patents.
US2187780A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lens system
Assignee: GAF Chemicals Corp
•
Filing: 1938-04-19
•
Granted: 1940-01-23
•
Expires: 1958-04-19
Abstract
No abstract record available.
Inventors
- 👤 Gehrke Friedrich Wilhelm
- 👤 Tiedeken Robert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:49
CPC Classifications
G; G02; G02B; G02B13/00
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1943-01-22 | 1943-07-24 | 1944-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-01-22 | 1947-07-24 | 1948-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-01-22 | 1951-07-24 | 1952-01-23 | $7700.00 | Window Closed / Lapsed |