OUTPUT CORRECTION UNIT OF IMAGE SENSOR

摘要

An image sensor (8) employing, on a pixel basis, a photosensor circuit, arranged to convert a sensor current flowing through a photoelectric conversion element PD depending on the quantity of incident light at the time of image pickup into a voltage signal with logarithmic characteristics under weakly inverted state utilizing the characteristics in the sub-threshold region of a transistor Q1, and to output a sensor signal according to the converted voltage signal, is further provided with means (12) for correcting variation in the output of each pixel using a sensor signal when the gate voltage VG and drain voltage VD of the transistor Q1 is switched to a level lower than the steady level at the time of image pickup while interrupting incident light to the photoelectric conversion element PD, and a sensor signal when the transistor Q1 is conducted by switching the gate voltage VG of the transistor Q1 to a level higher than the steady level at the time of image pickup so that variation in the output characteristics of each pixel can be corrected by creating the bright output state or dark output state of the image sensor artificially.