Multi-layer heater for an electron gun
US8547005B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 6, 2010 |
| Grant date | Oct 1, 2013 |
| Priority date | — |
| Expiry date | Mar 2, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J1/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The electron emission portion of a cathode for an electron gun has layers of substrate material formed from a ceramic powder such as Aluminum nitride. The substrate layers have conductive traces formed on them, the conductive traces made from sintered tungsten or alternatively a refractory foil. When current is passed through the conductive traces, heat is coupled to a cathode which is thermally coupled to the heater assembly. In another embodiment of the invention, one of the layers of the heater includes a thermionic emission material and optionally a work function lowering material such as BaO, which allows the outer layer of the multi-layer heater to directly emit electrons. In another embodiment of the invention, a control grid is formed on a layer above the thermionic cathode layer, which provides for a complete electron gun assembly having a heater, cathode with a reduced work function material, and control grid to be fabricated as a single unit at the same time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.