Electron gun for color picture tube with electrostatic focussing lens

摘要

An electron gun for color picture tube has a focusing electrode and an anode electrode respectively formed of an oval thick plate for forming main focusing lenses. Each of the focusing electrode and anode is formed with three electron beam passing holes arranged in line in a direction orthogonal to a tube axis of the picture tube. The focusing electrode and the anode are arranged to oppose each other with a distance therebetween such that their corresponding electron beam passing holes oppose each other. When predetermined voltages are applied to the focusing electrode and anode, main lenses are formed between the respective opposing holes. As viewed along the tube axis, the in line electron beam passing holes of each electrode include two outer electron beam passing holes each having an outer half in the form of a semi-circle and an inner half in the form of a semi-ellipse having a diameter of the semi-circle as its major axis and a central electron beam passing hole in the form of an ellipse having a major axis which is equal to the diameter of the semi-circle and which extends in a direction orthogonal to the direction of arrangement of the electron beam passing holes.