US2239416A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cathode for electron discharge devices
Assignee: EMI Ltd
•
Filing: 1940-01-24
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Granted: 1941-04-22
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Expires: 1960-01-24
Abstract
No abstract record available.
Inventors
- 👤 Ehrenberg Werner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:43
CPC Classifications
H; H01; H01J; H01J3/00; H01J3/02; H01J1/00; H01J1/02; H01J1/13; H01J1/20; H01J3/024; H01J35/00; H01J35/02; H01J35/14
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) | 1944-04-21 | 1944-10-21 | 1945-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-04-21 | 1948-10-21 | 1949-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-04-21 | 1952-10-21 | 1953-04-22 | $7700.00 | Window Closed / Lapsed |