US2591997A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron tube device
Assignee: Telefonaktiebolaget LM Ericsson AB
•
Filing: 1949-10-20
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Granted: 1952-04-08
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Expires: 1969-10-20
Abstract
No abstract record available.
Inventors
- 👤 Backmark Nils Erik Gustav
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:23
CPC Classifications
H; H01; H01J; H01J31/00; H01J31/02; H01J31/06; H01J21/00; H01J21/02; H01J21/18
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1721395A
Cited
US1585173A
Cited
US1558120A
Cited
US2103338A
Cited
US2173252A
Cited
US2432608A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-04-08 | 1955-10-08 | 1956-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-04-08 | 1959-10-08 | 1960-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-04-08 | 1963-10-08 | 1964-04-08 | $7700.00 | Window Closed / Lapsed |