Electron gun for a color cathode ray tube

摘要

An electron gun for a color cathode ray tube includes a last accelerating electrode having a large-caliber electron beam passing hole for commonly passing red, blue, and green electron beams. Both ends of the beam passing hole include circular arc portions formed with a predetermined curvature. The center portions where the green electron beam passes through protrude by a predetermined width. The length of the protrusion in the horizontal direction satisfies the following inequality: L<H-2R(1+cos alpha ), where H designates the horizontal width of the large-caliber electron beam passing hole, R is the radius of the circular arc portions and alpha is the angle between a line drawn from either center of the circular arc portions to an adjacent apex of the protrusions and a line connecting centers of both circular arc portions. By using the above-described device, the halo of an electron beam landing on a phosphor layer can be decreased, thereby enhancing the resolution of a cathode ray tube adopting the electron gun.