Abstract: A cathode ray tube has a panel portion 1 with a phosphor layer 5 formed on its inner face, a neck portion 2 accommodating an electron gun 9, a funnel portion 2 for coupling the panel portion 1 to the neck portion 2 and a color selective electrode assembly 6 having a number of electron beam passing openings arranged opposite to the phosphor layer 5 with a space therebetween. The color selective electrode assembly is installed within the panel portion 1. An electron beam reflection film of a bismuth oxide thin film 6R having a bulk density of from 4 to 9.3 g/cm.sup.3 is formed on the face of the color selective electrode assembly 6 against which the electron beams 14 emitted from the electron gun 9 collide. The cathode ray tube is capable of displaying high density and high resolution image.

Abstract: The color cathode ray tube of this invention improves the purity (color purity) adjustment margin and permits bright display without deteriorating the resolution. At least the black matrix holes 40g, 40b, 40r, forming the phosphor surface or the shadow mask apertures are so arranged that the center-to-center distance between the adjacent holes or apertures corresponding to the pixel phosphors of the same color in a vertical direction is greater by about 10 to 70% than the center-to-center distance in an inclined direction. Further, at least the black matrix holes or the shadow mask apertures are shaped non-circular with their vertical cross-section greater than their horizontal cross-section. With this invention it is possible to provide a color cathode ray tube which has improved brightness and purity (color purity) adjustment margin and a substantially enhanced resolution.