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:
Aug. 10, 2004
Filed:
May. 23, 2003
Akira Chiba, Sagamihara, JP;
NEC Microwave Tube, Ltd., Kanagawa, JP;
Abstract
An electron gun also has a cathode for emitting electrons, a heater cap which contains a heater for applying the cathode with thermal energy for emitting electrons, a retainer for securing the cathode on the heater cap by clamping the peripheral edge of the cathode onto the heater cap, and a cylindrical Wehnelt supporter. The cylindrical Wehnelt supporter has a Wehnelt electrode for focusing an electron beam that is formed in such a shape that an average angle of the surface thereof with respect to an outermost shell of the electron beam matches a Pierce angle, and three or more heater cap supporters for securely supporting the heater cap at a position at which an electron emitting surface of the cathode and an opening formed through the Wehnelt electrode satisfy a predetermined perveance.