Abstract: An electron gun for a color cathode ray tube having a cathode, a control electrode and a screen electrode together constituting of a triode, and a main lens for focusing and accelerating an electron beam formed by the triode. The electron gun is characterized by a horizontally elongated electron beam passing hole formed in the control electrode having its long axis disposed in the arrangement direction of the electron beam passing hole. A horizontally elongated slot encompassing the electron beam passing hole having its long axis disposed in the arrangement direction of the electron beam passing hole is formed in the screen electrode opposed to the control electrode, thereby preventing the focusing characteristics of the electron beam from being reduced throughout the surface of the fluorescent layer by the influence of the deflection yoke.

Abstract: A cathode structure for an electron gun of a cathode ray tube contains supporting pieces for preventing the detachment of an insulating block that are buried into insertion grooves made in the insulating block. These supporting pieces contact and are welded to the inside of the skirt of the control grid after they are inserted into the control grid together with the insulating block. This provides high stability against external impacts.