| 摘要 |
PROBLEM TO BE SOLVED: To obtain a superior resolution over the whole picture without bringing about insulation destruction or the like among electrode pins even a dynamic focus voltage is made to be increased accompanied with increase of the maximum deflection amount of an electron beam. SOLUTION: In an electron gun in which a first quadrupole lens L1 is formed that has a first and second convergence electrodes and a last accelerating electrode, and that has a convergence action in the horizontal direction among the first and second convergence electrodes and a diverging action in the vertical direction at no deflection time of the electron beam, while a dynamic focus voltage is superposed and applied to the second convergence electrode, the second convergence electrode and/or the last accelerating electrode are constituted so that components of the second quadrupole lens L2 is contained wherein a dynamic focus voltage of which fluctuation is smaller than that of the dynamic focus voltage applied the second convergence electrode is superposed and applied to the first convergence electrode, and so that the main lens Lm formed between the second convergence electrode and the last accelerating electrode offsets an action of the first quadrupole lens L1 at the no deflection time of the electron beam. COPYRIGHT: (C)2005,JPO&NCIPI
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