Patent US348839A successfully refreshed from Google Patents.
Patent US2158640A successfully refreshed from Google Patents.
US2158640A
Expired / Lapsed
US
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Electron discharge device
Assignee: EMI Ltd
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Filing: 1937-07-31
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Granted: 1939-05-16
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Expires: 1957-07-31
Abstract
No abstract record available.
Inventors
- 👤 Strange John William
- 👤 Connell William Horace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:04
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/74; H04N5/7416; H04N5/7425; H01; H01J; H01J29/00; H01J29/02; H01J29/10; H01J29/18; H01J29/34
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) | 1942-05-15 | 1942-11-14 | 1943-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1946-05-15 | 1946-11-14 | 1947-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1950-05-15 | 1950-11-14 | 1951-05-16 | $7700.00 | Window Closed / Lapsed |