PROBLEM TO BE SOLVED: To reduce a diameter in a horizontal direction of an electron beam spot and enlarge a diameter in a vertical direction of the electron beam spot by an electron gun.;SOLUTION: A main lens part is formed of a focusing electrode 20 and a final acceleration electrode 30. The final acceleration electrode is provided with a cylindrical electrode 31, and at least a pair of horizontal electrode plates 32 in an inside of the cylindrical electrode. The focusing electrode is provided with a cylindrical electrode 21, and a vertical electrode plate 22 provided in a position retracting from an side end of the final acceleration electrode of the cylindrical electrode. Three openings 23B, 23G, 23R where three electron beams respectively pass are formed on the vertical electrode plate of the focusing electrode. Maximum opening diameters in a vertical direction of the respective three openings do not exceed maximum opening diameters in a horizontal direction.;COPYRIGHT: (C)2007,JPO&INPIT
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