PURPOSE: To make display with high resolution and to make exact gradation display by modulating the output light of an exposing means for exposing a photoconductive layer in accordance with a signal indicating the multiple gradation densities of images and controlling the light transmittance of the light controllable layer.
CONSTITUTION: A voltage is applied by' a voltage source 3 to the light controllable layer 1 and photoconductive layer 2 having a light scattering state over the entire surface. The photoconductive layer 2 is irradiated with light from an exposure device 4 modulated in exposure time by a gradation controller 5 in accordance with the multiple gradation densities information of the writing images indicated by image density signals. The electric conductivity changes according to the degree of modulation in the exposed regions of the photoconductive layer 2 and the voltage of the quantity meeting the change is impressed to the light controllable layer 1. The transparency, i.e. degree of gradation, of the light controllable layer 1 is determined according to the voltage impression state. On the other hand, the electrical conductivity remains low in the unexposed regions of the photoconductive layer 2 and there is substantially no voltage to be impressed to the light controllable layer 1 and, therefore, the light scattering state is still maintained. As a result, the images of the multiple gradation densities are written on the light controllable layer 1.
KAKINUMA TAKEO
ITO KENSUKE
