Patent ID: 6366011
Filing Date: 2002-04-02
Classification: H01J

Abstract:
An electron gun for a cathode-ray tube for image display comprising:a cathode having a sleeve made of a refractory metal, a support provided at one end of said sleeve and made of a refractory metal containing a reducing element, a heater arranged in a space defined by said sleeve and said support, an electron emissive material layer for emission of electrons, said electron emissive material layer being mainly made of an oxide of an alkaline earth metal and containing an oxide of a rare earth metal, said electron emissive material layer being prepared by the steps of: (a) forming a first layer on said support by spraying, and (b) forming a second layer on said first layer by spraying, wherein a dispersion amount of an oxide of a rare earth metal in said second layer is larger than that in said first layer; and a first grid electrode provided adjacent said cathode, said grid electrode having an electron beam passage hole for the electrons from said electron emissive material layer, said electron beam passage hole having a diameter which is less than 0.4 mm.