| 摘要 |
PURPOSE:To make the uniformity of resolution and focus ability of an electron gun the same as or higher than the other electron guns even though a current larger than the others flows to the electron gun to excite a phosphor of a lower luminous efficiency, by making the opening diameter of at least the control electrode, of the control electrode and the acceleration electrode of the electron gun responding to the phosphor of the lowest luminous efficiency. CONSTITUTION:The opening diameter D1 of the control electrode 1R of the central electron gun 10R which excites the red phosphor of the worst luminous efficiency is set smaller than the opening diameter D2 of the control electrodes 1G and 1B of the both side electron guns 10G and 10B. Therefore, even though a much larger current is picked up from the central electron gun 10R, in order to obtain a same level brightness as the phosphor excited by the electron guns 10G and 10B of the both side, or a standard white color of 9,300 deg.K, for example, an increase of crossover images can be limited, because the opening diameter D1 of the control electrode 1R is smaller than the opening diameter D2 of the other control electrodes 1G and 1B.
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