| 摘要 |
PURPOSE:To permit the shortening of electron gun without impairing the scale factor of lens by giving a comparatively high potential to a focusing electrode and also by providing a cylindrical electrode with a lower potential than that of the focusing electrode between the focusing electrode and anode. CONSTITUTION:The cylindrical electrode 14 whose potential is kept lower than that of a focusing electrode is provided between the focusing electrode 5 whose potential is set up to 7-10kV and the anode (final acceleration electrode) 8. Thus, the electron beam 9 emitted at the angle of alpha1 from the crossover image point 0 is once bent outwards by the equipotential line 15 of the divergencing action region (a) to expand it to a necessary beam diameter and then focused by the equipotential lines 16 and 17 of the focusing action region (b) to direct it to the fluorescent screen 12 at the angle of alpha2. Thus, the length of the electron gun can be shortened without increasing the scale factor of lens. |
