US2647220A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron tube structure for the production of annular beams of electrons
Assignee: EMI Ltd
•
Filing: 1946-10-05
•
Granted: 1953-07-28
•
Expires: 1966-10-05
Abstract
No abstract record available.
Inventors
- 👤 Broadway Leonard Francis
- 👤 Barford Norman Charles
- 👤 Pearce Albert Frederick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:40
CPC Classifications
G; G03; G03G; G03G13/00; G03G13/26; G03G13/28; H; H01; H01J; H01J25/00; H01J25/02; H01J25/10; H01J25/14; H01J25/22; H01J25/26; H01J29/00; H01J29/46; H01J29/58; H01J29/62; H01J29/622; H01J29/624; H01J3/00; H01J3/02; H01J3/029
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2035623A
Cited
US2005330A
Cited
US2103645A
Cited
US2233126A
Cited
US2139487A
Cited
US2151765A
Cited
US2200745A
Cited
US2276806A
Cited
US2259690A
Cited
US2407274A
Cited
US2409224A
Cited
US2409693A
Cited
US2392380A
Cited
US2400743A
Cited
US2468152A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-07-27 | 1957-01-26 | 1957-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-07-27 | 1961-01-26 | 1961-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-07-27 | 1965-01-26 | 1965-07-28 | $7700.00 | Window Closed / Lapsed |