Patent US2389935A successfully refreshed from Google Patents.
US2389935A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microphonic electron tube
Assignee: Individual
•
Filing: 1943-06-24
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Granted: 1945-11-27
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Expires: 1963-06-24
Abstract
No abstract record available.
Inventors
- 👤 Rothstein Jerome
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:52
CPC Classifications
H; H01; H01J; H01J21/00; H01J21/02; H01J21/06; H01J21/08; H04; H04R; H04R17/00; H04R17/02; H04R17/04
Claims Analysis
Total Claims: 0
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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) | 1948-11-26 | 1949-05-28 | 1949-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1952-11-26 | 1953-05-28 | 1953-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1956-11-26 | 1957-05-28 | 1957-11-27 | $7700.00 | Window Closed / Lapsed |