US2660923A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase contrast apparatus for metallographic microscopes
Assignee: Bausch and Lomb Inc
•
Filing: 1949-10-06
•
Granted: 1953-12-01
•
Expires: 1969-10-06
Abstract
No abstract record available.
Inventors
- 👤 James R Benford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:45
CPC Classifications
G; G02; G02B; G02B21/00; G02B21/06; G02B21/08; G02B21/14
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-11-30 | 1957-06-01 | 1957-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-11-30 | 1961-06-01 | 1961-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-11-30 | 1965-06-01 | 1965-12-01 | $7700.00 | Window Closed / Lapsed |