| 摘要 |
PURPOSE:To reduce the quantity of consumed beam by cutting off beams excluding one beam which can be passed through a pore based on an index signal at the time of selecting three beams by a mask member having the pore for selecting a color. CONSTITUTION:As a color selection mechanism on a fluorescent surface 2, an aperture grill 3 is used, the three color beams 1a-1c are controlled so as to be converted on the color fluorescent material 4 of the fluorescent surface 2 and horizontally and vertically deflected by a deflecting system. A light emission when the beams 1a-1c strike a fluorescent material 5 for an index applied on the aperture grill 3 is detected to detect the scanning positions of the respective beams. The two beams which are not selected but strike the aperture grill 3 are cut off. Accordingly, only the color selected beam passing through the pore 3a of the aperture grill 3 reach the fluorescent surface 2.
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