| 摘要 |
PURPOSE:To obtain good resolution all over a screen by a method wherein in the first part of a focusing electrode system consisting of the first - third grid electrodes, any one of them is made to be a beam pass hole of an axially asymmetrical type while the fixed focusing voltage is applied to the first and the third electrodes and the dynamic voltage is applied to the second electrode. CONSTITUTION:In an electron gun 9 consisting of three electrodes 10'-10''' arranged on a horizontal straight line, that is, a control electrode 11, an acceleration electrode system 12, the first part and the last part focusing electrode systems 13 and 14, the first focusing electrode system 13 consists of the first - the third grid electrodes 15-17 along an electron beam passage. Said first and third electrodes 15 and 17 are made to have each group of three cylindrical beam passage holes 18'-18''' and 19'-19''' while the second electrode 16 is made to have the vertically long rectangular beam passage holes 20'-20'''. Further a fixed focusing voltage Vfoc is applied to the first and the third electrodes 15 and 17 while the dynamic voltage V'foc, which changes according to a beam deflection quantity, is made to be applied to the second electrode 16. |
