Patent US4250429A successfully refreshed from Google Patents.
US4250429A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron tube cathode
Assignee: US Philips Corp
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Filing: 1977-10-25
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Granted: 1981-02-10
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Expires: 1997-10-25
Abstract
Abstract Cathodes having a support for emissive material of foamed carbon are mechanically stable and resistant to detrition and have a homogeneous pore distribution.
Inventors
- 👤 Bernhard Lersmacher
- 👤 Hans Lydtin
- 👤 Horst Seifert
- 👤 Johannes W. A. Krol
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:33
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/20; H01J1/26
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
24 words
A cathode for an electron tube, said cathode comprising a support made of foamed carbon having a net-like structure and containing an emissive material.
Claim 2
Dependent Claim
24 words
A cathode for an electron tube, said cathode comprising a support made of foamed carbon having a net-like structure and containing an emissive material.
Claim 3
Dependent Claim
32 words
A cathode according to claim 1, wherein said support has pore channels which are deformed so that preferred directions are formed for transport of said emissive material during operation of said cathode.
Claim 4
Dependent Claim
19 words
A cathode according to claim 1, wherein said support has a surface at least partly coated with a metal.
Claim 5
Dependent Claim
15 words
A cathode according to claim 1, wherein said support is impregnated with said emissive material.
Claim 6
Dependent Claim
15 words
A cathode according to claim 1, wherein means are included for indirectly heating said support.
Claim 7
Dependent Claim
15 words
A cathode according to claim 1, wherein means are included for directly heating said support.
Claim 8
Dependent Claim
23 words
A cathode according to claim 1, wherein said emissive material is intermixed with a starting material from which said carbon support is made.
Claim 9
Dependent Claim
21 words
A cathode for an electron tube, said cathode comprising a support made of syntactic foamed carbon and containing an emissive material.
Claim 10
Dependent Claim
21 words
A cathode for an electron tube, said cathode comprising a support made of syntactic foamed carbon and containing an emissive material.
Claim 11
Dependent Claim
19 words
A cathode according to claim 8, wherein said support has a surface at least partly coated with a metal.
Claim 12
Dependent Claim
15 words
A cathode according to claim 8, wherein said support is impregnated with said emissive material.
Claim 13
Dependent Claim
15 words
A cathode according to claim 8, wherein means are included for indirectly heating said support.
Claim 14
Dependent Claim
15 words
A cathode according to claim 8, wherein means are included for directly heating said support.
Claim 15
Dependent Claim
23 words
A cathode according to claim 8, wherein said emissive material is intermixed with a starting material from which said carbon suupport is made.
Claim 16
Dependent Claim
24 words
A cathode for an electron tube, said cathode comprising a support made of carbonized rigid phenol aldehyde resin fabric and containing an emissive material.
Claim 17
Dependent Claim
24 words
A cathode for an electron tube, said cathode comprising a support made of carbonized rigid phenol aldehyde resin fabric and containing an emissive material.
Claim 18
Dependent Claim
19 words
A cathode according to claim 14, wherein said support has a surface at least partly coated with a metal.
Claim 19
Dependent Claim
15 words
A cathode according to claim 14, wherein said support is impregnated with said emissive material.
Claim 20
Dependent Claim
15 words
A cathode according to claim 14, wherein means are included for indirectly heating said support.
Claim 21
Dependent Claim
15 words
A cathode according to claim 14, wherein means are included for directly heating said support.
Claim 22
Dependent Claim
23 words
A cathode according to claim 14, wherein said emissive material is intermixed with a starting material from whch said carbon support is made.
References Cited (Backward Citations)
US3454816A
Cited
US3856574A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-10 | 1984-08-11 | 1985-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-10 | 1988-08-11 | 1989-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-10 | 1992-08-11 | 1993-02-10 | $7700.00 | Window Closed / Lapsed |