| 摘要 |
PURPOSE:To uniformalize focusing voltages in the vertical and horizontal directions by shaping an aperture of at least one of electrodes, which compose a main electronic lens, so that its diameter in the vertical direction is different from that in the horizontal direction when an electron beam transmission aperture is formed so that diameters are different from each other in the vertical and horizontal directions is formed. CONSTITUTION:When an electron beam transmission aperture h1 at the first grid G1 is formed into a vertically long shape, for example, a difference in focusing voltages, which is based on a difference in positions of crossover points concerning the horizontal and vertical directions, is formed into a difference in main electronic lens effects concerning the horizontal and vertical directions by selecting an electron beam transmission aperture hA of an anode electrode to which a high voltage is applied to compose the main electronic lens. Thus, a focusing voltage can be uniformalized in the horizontal and vertical directions of the electron beams in order to obtain just focusing on a fluorescent screen. Besides, an electron beam spot on the fluorescent screen can be set in the narrowest shape, and a shift in coloring can be avoided, so that resolution can be improved.
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