| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cathode ray tube mounting an electron gun having an indirectly heated cathode structure obtaining high current density and stable electron emission property for long time. SOLUTION: An indirectly heated cathode structure is composed of a base metal 53 holding an electron emission material 54A containing a plurality of alkali earth metal oxide at least containing barium as main components, and a cathode sleeve 52 housing a heater 55 insides. The base metal 53 is made of nickel as a main component and includes very small quantity of reductive element, and the electron emission material 54, composed of metal oxide 54A of barium, calcium, and strontium, includes very small quantity of antimony oxide 54B.
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