| 摘要 |
PURPOSE:To obtain beams having good focusing capability by arranging a modulation electrode which is divided into several sections and several slits, a plurality of switching electrodes each of which has the same constitution as the modulation electrode, and a plurality of focus electrodes. CONSTITUTION:A modulation unit of flat type cathode ray tube is formed in such a manner that a modulation electrode 44 which is divided into multiple groups each of which has three slits, switching electrodes 43 and 44 each of which has the same constitution as the modulation electrode but its slit locations are shifted by 1/3 pitch, and shielded electrodes 41 and 45 which are placed on both sides of these electrodes and whose slits are faced to those of these electrodes are arranged, and focus electrodes 46 and 47 which also serve as landing correction electrodes are placed between the shielded electrode and a fluorescent screen 48. Deflection of passing beam influenced by cut-off voltage which generates when divided width of the modulation electrode or switching electrode is smaller than the distance between electrodes is reduced and halation on the fluorescent screen is removed. |
