To greatly improve a white balance in the early start time of a cathode-ray tube operation, especially concerning an oxide cathode body structure used in the cathode-ray tube, and also to obtain an oxide cathode body structure and an electron gun which can be operated rapidly with a low heater input power.
This oxide cathode body structure comprises a cathode sleeve 1 such that a metal-oxide blackened layer is formed on its surface, a heater 8 arranged inside the cathode sleeve 1, and a cylinder body fitted on the upper circumference of the cathode sleeve 1. A part of the cylinder body is bound near the upper end of the cathode sleeve 1. The upper end of the cylinder body is extended exceeding the cathode sleeve 1, and a cathode substrate metal 3 is fixed on its upper end. The lower end of the cylinder body has a reflective member 2, which has no metal-oxide blackened layer on the circumferential surface being extended as far as the halfway of the cathode sleeve 1, and a support member 5, which is arranged on the same shaft around the lower part of the cathode sleeve 1. The subject electron gun is composed by using this body structure. Hereby, the position change of relative distance of a thermoelection-emitting face to the primary electrode 9 of the electron gun is suppressed to the minimum, and the cathode substrate metal 3 is separated from the cathode sleeve 1 comprising a chromium alloy, and Cr in the chromium alloy is diffused into the cathode substrate metal 3 during the operation, to thereby prevent a reaction with thermoelection- emissitting material.
HIGUCHI TOSHIHARU
MATSUMOTO SADAO
