IMPREGNATED CATHODE STRUCTURE, CATHODE SUBSTRATE USED FOR IT, ELECTRON GUN STRUCTURE USING IT, AND ELECTRON TUBE

摘要

PROBLEM TO BE SOLVED: To provide a superior characteristic impregnating cathode ray structure having ion bombardment resistance by providing a large-grain-size, low- void-ratio range which has specific values for mean grain size, porosity and contains an electron emitting material, and a small-grain-size, high-void-ratio range having specific vales of a mean grain size and a void ratio in a porous cathode substrate. SOLUTION: A large-grain-size, low-void-ratio range 22 which has a mean grain size 2-10μm, a void ratio 15-25%, and has an electron emitting material 24 impregnated, and a small-grain-size, high-void-ratio range 23 having a mean grain size 0.1-2.0μm and a void ratio 25-40% are provided in an electron emission face side of a porous cathode substrate so as to be formed into a cathode ray structure. This constitution provides an impregnating cathode structure having sufficient ion bombardment resistance and superior electron emission characteristics even under high voltage and high frequency conditions.