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Patent Searching and Data


Title:
IMPROVED CATHODE FOR MICROWAVE TUBE
Document Type and Number:
Japanese Patent JPH04286837
Kind Code:
A
Abstract:
PURPOSE: To correct abnormal distribution of an electric field in the peripheral part of a cathode and smooth emitted electron beam by forming the peripheral part of the cathode of an electron gun of a microwave tube using an electron non-emissive material. CONSTITUTION: A main body of a cathode is a porous conductor 1 impregnated with an electron emissive material and heated to a high temperature and kept at negative high voltage. The surface is a pellet having a recessed shape, an electric field is generated perpendicularly to the surface, and electrons spring out of the surface and are accelerated uniformly in the center part by the electric field. To rectify the electric field in the peripheral part of the cathode 1 to be uniformly centripetal, a Wehnelt electrode 2 is formed away from the peripheral part and further a ring 3 is installed in the inside. The ring 3 is made of carbon or a high melting point carbide and scarcely carries out thermionic emission. Due to the installation of the Wehnelt electrode 2 and the ring 3, electric power lines are made smooth as illustrated and the performance of an electron gun can be remarkably improved.

Inventors:
JIYORUJIYU MURIE
ARUBUAN SHIYUROFU
Application Number:
JP33759891A
Publication Date:
October 12, 1992
Filing Date:
November 27, 1991
Export Citation:
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Assignee:
THOMSON TUBES ELECTRONIQUES
International Classes:
H01J1/13; H01J1/20; H01J23/04; H01J25/00; (IPC1-7): H01J1/13; H01J23/04; H01J25/00
Attorney, Agent or Firm:
Takashi Koshiba