Thermionic cathode and method of manufacturing same
US4524297A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 13, 1982 |
| Grant date | Jun 18, 1985 |
| Priority date | — |
| Expiry date | Sep 13, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J9/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A cathode having a layer structure in which alternate layers consisting essentially of emitter material (2) and base material (1) are provided at an oblique angle to the cathodes's macroscopic emitting surface. In a preferred embodiment the surface has a microscopically stepped structure formed by ends of the base material layers and portions of the emitter material layers coating the ends. In an alternative embodiment the surface is not stepped but is formed by a polycrystalline or a preferentially oriented polycrystalline coating layer which is provided on the succession of beveled layers. The succession of layers is manufactured by alternating depositions from the gaseous phase and by subsequent bevel grinding of the layers. The polycrystalline coating layer is provided by deposition from the gaseous phase. The stepped surface is formed, for example, by selective structure etching after the bevel grind.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.