US2538840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Still projector for opaque and transparent projection
Assignee: American Optical Corp
•
Filing: 1947-10-15
•
Granted: 1951-01-23
•
Expires: 1967-10-15
Abstract
No abstract record available.
Inventors
- 👤 David D Lowber
- 👤 Fred H Wolford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:24
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/08
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-01-22 | 1954-07-24 | 1955-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-01-22 | 1958-07-24 | 1959-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-01-22 | 1962-07-24 | 1963-01-23 | $7700.00 | Window Closed / Lapsed |