| 摘要 |
PURPOSE:To reduce the astigmatism of a main electron lens by providing the beam transmitting holes of opposed electrodes, which form the main electron lens, with conductive partition walls protruding from the inner surface of the electrodes in the axial direction. CONSTITUTION:Opposed electrodes 4 and 5 form the main electron lens of a color image receiving tube electron gun, and are provided with side beam transmitting holes 4G2, 4B2, and 5G, 5B and central beam transmitting holes 4R2 and 5R respectively. Cylindrical partition walls 18, which have the same axis as the beam transmitting hole, protrude from the peripheries of the side beam transmitting holes toward the inner side of the electrodes 4 and 5 in the axial direction, and have a length above one third of the diameter of the beam transmitting hole, are provided between the beam transmitting holes. Since equipotential lines 19 form an almost symmetrical pattern on both sides of the space between the electrodes 4 and 5, and the lines 19 become symmetrical about axial lines 9, 10 and the like owing to the electrostatic shield effect of the partition walls 18, which remove any influence of adjacent holes, a homogeneous electron lens with a small astigmatism can be obtained. Consequently, a beam spot formed on a fluorescent surface can be made closer to a true circle. |
