Patent ID: 7122950

Claim:
A electron gun for a color cathode ray tube comprising: a cathode that emits electron beams; a plurality of electrodes arranged from the cathode towards a screen of the cathode ray tube; and a shield cup, wherein the shield cup further comprises: a central electron beam hole; two outer electron beam holes wherein the central and outer beam holes are substantially collinear along a horizontal axis; and first, second, third, and fourth magnetic pieces; wherein the first and second magnetic pieces are adjacent to a first outer electron beam hole and on opposite sides of the horizontal axis; and wherein the third and fourth magnetic pieces are adjacent to a second outer electron beam hole and on opposite sides of the horizontal axis; and wherein a first distance l′ is defined as the distance between the center of the central electron beam hole and the first end of the magnetic pieces along the horizontal axis, a second distance l is defined as the distance between the center of the central electron beam hole and the center of the outer electron beam holes; and the electron beam holes and magnetic pieces are arranged so that l′/l greater than or equal to 0.5 and less than or equal to 1.0.