| 摘要 |
PROBLEM TO BE SOLVED: To provide an electron gun in which, the aberration in a large aperture main lens is decreased, large aperture is realized, assembly precision is and a preferred image property can be obtained in the whole image area. SOLUTION: In the electron gun, the main focus lens comprises a focus electrode G5 with middle level focus voltage applied, an anode electrode G6 applied with high level anode voltage, and a middle electrode GM which is placed between the focus electrode G5 and the anode electrode G6 and has middle potential in the middle potential of the middle-high potential which is higher than the focus voltage and lower than the anode voltage. The anode electrode G6 and the middle electrode GM is a long cylinder body in the direction of common inline to 3 electron beams, and with respect to the open aperture crossing with right angle to the inline direction of the cylinder body, the open aperture of the anode electrode G6 is determined to be made smaller than the open aperture of the middle electrode GM, multiple electrode lens which is common to the 3 electron beams is formed as the large aperture main focus lens.
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