| 摘要 |
PROBLEM TO BE SOLVED: To aim at higher resolution by making beam spots in an optimum shape over the whole area of an image screen. SOLUTION: With an electron gun provided with at least a front-stage electrostatic quadrupole lens LQ1 and a back-stage electrostatic quadrupole lens LQ2 between electron beam generating parts (K, G1, G2) and a main lens LM, the back-stage electrostatic quadrupole lens LQ2 is provided with a pair each of horizontal plate electrodes HB1, HB2, HG1, HG2. HR1, HR2 pinching each of three beams from the direction orthogonal to an inline direction, of which, the pairs of the horizontal plate electrodes HB1, HB2, HR1, HR2 pinching each of side beams are set open toward a center beam side, and magnifying capacities of two lenses through which each side beam of the back-stage quadrupole lens LQ2 passes are made differentiated from the center-beam side to the contrary side in the inline direction. With this, deflection aberration due to difference in left and right distances from each of the side beams to deflection yokes in accordance with deflection angles is corrected.
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