Abstract: A liquid crystal light valve has a photoconductive layer between a pair of electrodes, and a liquid crystal layer. The resistivity of the photoconductive layer at the portion which is irradiated with light is reduced by partial light irradiation. By applying a voltage between the electrodes in this state, the voltage is applied to the liquid crystal layer in the portion which is irradiated with light and the crystalline structure at this portion is changed, thereby enabling image data writing. The photoconductive layer is a laminate of an amorphous Si film and an inorganic insulating film disposed on the electrode side, which structure suppresses the carrier injection from the electrode to the amorphous Si film. The polarity of a voltage for writing image data into the liquid crystal light valve is inverted for every horizontal scanning operation. That is, writing of black portions on a white background and writing of white portions on a black background are alternately executed.

Abstract: A liquid crystal light valve has a photoconductive layer between a pair of electrodes, and a liquid crystal layer. The resistivity of the photoconductive layer at the portion which is irradiated with light is reduced by partial light irradiation. By applying a voltage between the electrodes in this state, the voltage is applied to the liquid crystal layer in the portion which is irradiated with light and the crystalline structure at this portion is changed, thereby enabling image data writing. The photoconductive layer is a laminate of an amorphous Si film and an inorganic insulating film disposed on the electrode side, which structure suppresses the carrier injection from the electrode to the amorphous Si film. The polarity of a voltage for writing image data into the liquid crystal light valve is inverted for every horizontal scanning operation. That is, writing of black portions on a white background and writing of white portions on a black background are alternately executed.

Abstract: A hologram scanner includes a rotatable hologram disk on which a plurality of hologram lenses are arranged circumferentially, and a light beam guide mechanism for successively shifting irradiation regions in a predetermined direction with respect to the direction of rotation of the hologram disk, to apply a light beam successively to the hologram lenses on the hologram disk, so that the scanning of a reading window with the light beam is effected in all directions with high density. The hologram scanner is employable as a bar code reading device in a POS or UPC system.