Patent ID: 6888299

Claim:
An electron gun for a cathode ray tube comprising: a cathode for emitting an electron beam; a plurality of grid electrodes aligned sequentially from the cathode, one of the grid electrodes including a plurality of focusing electrodes that are mounted with at least one predetermined gap therebetween; a support for fixing the grid electrodes in their aligned arrangement; and a shield electrode mounted covering the at least one gap of the focusing electrodes and extending a predetermined distance over the focusing electrodes, wherein a plurality of openings are formed at predetermined distances through the shield electrode, and the shield electrode is cylindrical and is mounted on the focusing electrodes covering the at least one gap and wherein the shield electrode satisfies the following condition: 0.25d mm 2 <c mm 2 <0.75d mm 2 where (c) is a total area of the openings and (d) is an area of the shield electrode minus the area occupied by the openings.