IMAGE SENSOR

PROBLEM TO BE SOLVED: To restrain a variation in sensor signal caused by an advance of photoreception during the read-out of each pixel by actuating a pseudo shutter function by controlling a charge storage time in response to incident light in each pixel when the sensor signal is read out from each pixel in time series. SOLUTION: In the image sensor which stores electric charges on the parasitic capacitance of a photoelectric conversion element with a logarithmic characteristic in a weakly reversed state using a characteristic of a sub-threshold region of a transistor in response to a sensor current flowing through the photoelectric conversion element in response to an incident luminous quantity, in which the pixeles each of which is composed of a light sensor circuit for outputting the sensor signal in response to its charging voltage are arranged in a matrix and in which scanning for read-out of the sensor signal is conducted in time series for each pixel, an initializing means is provided in which a drain voltage of the transistor for logarithmic characteristic conversion for all pixels is simultaneously switched to obtain a lower value than a steady-state value preliminarily and the read-out of the sensor signal of each pixel is started when a certain time is passed from initialization. COPYRIGHT: (C)2005,JPO&NCIPI