| 摘要 |
PROBLEM TO BE SOLVED: To improve resolution by optimally shaping a beam spot in a whole area of a screen. SOLUTION: An electron gun is provided with a third electrode 4 divided into a third electrode of a first kind 41 and a third electrode of a second kind 42. A constant voltage (Vf1) as a first focusing voltage is applied to the third electrode of the ?t kind 41. A voltage (Vf2+dVf) superimposing a dynamic voltage (dVf) varying in synchronization with a change of a deflection angle for scanning an electron beam on the screen on a constant voltage (Vf2) as a second focusing voltage is applied to the third electrode of the second kind 42. An electrostatic quadrupole lens for reshaping the electron beams is installed between the third electrode of the first kind 41 and the third electrode of the second kind 42, and the third electrode of the first kind and the electrostatic quadrupole lens for reshaping the electron beams are provided. In this electron gun, the electron beams are dispersed in a horizontal direction and are focused in a perpendicular direction to traveling directions of the electron beams with an increase of a potential difference between a voltage applied to a fourth electrode 5 and the second focusing voltage between the fourth electrode 5 and an open hole 42a on the third electrode of the first kind 41 side of the third electrode of the second kind 42 adjacent to the fourth electrode 5.
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