ELECTRON GUN FOR CATHODE-RAY TUBE AND CATHODE-RAY TUBE USING SAME

PURPOSE: To provide an electron gun for a cathode-ray tube having simple constitution, a large aperture and low spherical aberrations. CONSTITUTION: Three small-aperture front electron lenses 18R, 18G, 18B are arranged in a straight line, and the optical axis 20G of the center front electron lens 18G is made to coincide with the optical axis 21 of a rear electron lens 19. Further, the front electron lenses 18R, 18B on both sides and the rear electron lens 19 perform concentration and convergence of an electron beam simultaneously, and the front and rear electron lenses 18, 19 are arranged so that Fraunhofer requirements are met.