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US 7,176,610 B2Granted
High brightness thermionic cathode
AssigneeToshiba Machine America, Inc.
InventorVictor Katsap
Life of this patent
Estimating the term…
Abstract
An improved thermionic cathode is provided. The cathode has a carbon-coated cone surface and reduced cone angle (e.g. typically 60 degrees or less) that delivers an electron beam with high angular intensity and brightness and exhibits increased longevity.
Claims25
A thermionic cathode comprising
- a crystalline emitter having a tip and a cone and sides, wherein said cone is positioned between said tip and said sides;
- and
- a carbon coating applied to an outer surface of said cone, wherein said sides of said crystalline emitter are not carbon coated.
An improvement in a thermionic cathode having a crystalline emitter with a tip and a cone and sides, wherein said cone is positioned between said tip and said sides, the improvement comprising:
- a carbon coating applied to an outer surface of said cone, wherein said sides of said crystalline emitter are not carbon coated.
An electron emission apparatus, comprising
- a thermionic cathode comprising
- a crystalline emitter having a tip and a cone and sides, wherein said cone is positioned between said tip and said sides;
- and
- a carbon coating applied to an outer surface of said cone, wherein said
- sides of said crystalline emitter are not carbon coated;
- an emitter heater;
- and
- a support for said crystalline emitter.
5 more elements
A method of manufacturing a crystalline emitter for use in a thermionic cathode, comprising the step of
- applying a carbon coating to an outer surface of a cone of said crystalline emitter, wherein said carbon coating is not applied to sides of said crystalline emitter which are located below said cone.
Dependencies are inferred from the claim text.