| 摘要 |
PURPOSE:To eliminate a repetition of flickering of a lamp at every time of loading and detaching a film, and to extend a life of the lamp, by providing a projection plane illuminance adjusting device between an information recording medium and a plane of projection. CONSTITUTION:Between a projection lens 12 and a screen 13, a projection plane illuminance adjusting device 16 is provided. The device 16 has a shutter 18 for turning in the direction orthogonal to th paper surface centering around a shaft 17, and a driving device 19 of a motor, etc., for driving the shaft 17, and also, has a control device for controlling the driving device 19. The shutter 18 is formed like a sector, and three through holes are provided in one line along its peripheral direction. Also, the hole positioned in a side edge part of the left side is closed up by a color filter 18a, and on the other hand, the hole positioned in a side edge part of the right side is closed up by a light shielding plate 18b through which a light beam is not made to transmit, and also, the hole of the center part is left as a hole 18c as it is.
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