US4178530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron tube with pyrolytic graphite heating element
Assignee: US Philips Corp
•
Filing: 1978-07-11
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Granted: 1979-12-11
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Expires: 1998-07-11
Abstract
Abstract In a thermionic cathode having a planar emissive body and a heating element of pyrolytic graphite which is provided on the side of the emissive body remote from the emissive surface of the emissive body, a uniform temperature distribution adjusts during operation throughout the overall emissive surface when the heating element is planar and the crystallographic c-axis of the pyrolytic graphite extends everywhere normal to the surface of the heating element facing the emissive body. As a result of this the possibility is obtained of realizing a planar, "rapid", induction-free unipotential cathode having a substantially ideal homogeneous temperature distribution.
Inventors
- 👤 Bernhard Lersmacher
- 👤 Hans Lydtin
- 👤 Horst Seifert
- 👤 Johannes W. A. Krol
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:24
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/20; H01J1/24
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
66 words
An electron tube comprising a thermionic cathode including a planar emissive body having an emissive surface and a heating element of pyrolytic graphite which is provided on the side of the emissive body remote from said emissive surface wherein the heating element is planar and the crystallographic c-axis of the pyrolytic graphite extends everywhere normal to the surface of the heating element facing the emissive body.
Claim 2
Dependent Claim
66 words
An electron tube comprising a thermionic cathode including a planar emissive body having an emissive surface and a heating element of pyrolytic graphite which is provided on the side of the emissive body remote from said emissive surface wherein the heating element is planar and the crystallographic c-axis of the pyrolytic graphite extends everywhere normal to the surface of the heating element facing the emissive body.
Claim 3
Dependent Claim
45 words
An electron tube as claimed in claim 1, wherein the heating element of the thermionic cathode is provided with connections for current passage in a manner such that the current flows preferentially with its main component parallel to the laminated structure of the pyrolytic graphite.
Claim 4
Dependent Claim
27 words
An electron tube as claimed in claim 1 or 2, wherein the emissive body of the thermionic cathode is provided as a layer on the heating element.
Claim 5
Dependent Claim
31 words
An electron tube as claimed in claim 1 or 2, wherein the heating element comprises areas of higher electron emission provided at least partly by reactive conversion or by ion implantation.
Claim 6
Dependent Claim
28 words
An electron tube as claimed in claim 1 or 2, wherein the emissive body of the thermionic cathode is separated from the heating element by an intermediate space.
References Cited (Backward Citations)
US3389290A
Cited
US3591822A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-10 | 1983-06-11 | 1983-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-10 | 1987-06-11 | 1987-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-10 | 1991-06-11 | 1991-12-11 | $7700.00 | Window Closed / Lapsed |