| 摘要 |
PURPOSE:To prevent a double exposure state from being generated, by setting the moving direction of a shutter in the same direction with the direction vertical to the scan of an image pickup plane, and controlling the rotation of a shutter so as to prevent the passing a scanning position in an effective picture plane by the edge part of an aperture part, or vice versa. CONSTITUTION:A pair of fan-shaped aperture parts 2 and 3 having an angle interval of 180 deg. are provided at a shutter 1, and also, a pair of position detecting slits 4 and 5 having the angle interval of 180 deg. are provided at a prescribed position outside of the aperture parts 2 and 3. An image pickup plane 8 is arranged so as to correspond to the aperture parts 2 and 3 of the shutter 1, and is scanned in order by an electron beam in arrow head direction of broken line in figure. The shutter 1 is rotated at prescribed speed (1800rpm) and phase in the direction almost coinciding with the vertical direction of the scan of the image pickup plane 8. In this way, the double exposure state can be prevented, and a charging pattern is scanned with a prescribed timing by the electron beam, then a video signal can be taken out.
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