The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 13, 2008
Filed:
Nov. 29, 2002
Jean-luc Ricaud, Dijon, FR;
Jean-michel Roquais, Dijon, FR;
Jean-Luc Ricaud, Dijon, FR;
Jean-Michel Roquais, Dijon, FR;
Thomson Licensing, Boulogne Billancourt, FR;
Abstract
Impregnated cathode for a vacuum tube comprising an emissive part in the form of a porous pellet impregnated with a compound of alkaline earth metals; the pellet is placed in a dish made of a refractory material and covered with a porous metal foil forming the emissive surface of the cathode. Moreover, the pellet has a separation surface between a heavily impregnated zone and a zone which is not impregnated or weakly impregnated so that the said separation surface comprises at least a hollow part facing the emissive surface. By virtue of the shape of this separation surface, the lifetime of the cathode is improved.