| 摘要 |
PROBLEM TO BE SOLVED: To avoid afterimage even if the light amount of the incident light is small for an image sensor using an optical sensor circuit as a pixel to convert a sensor current flowing through a photoelectric conversion element according to an incident light amount into an voltage signal with a logarithmic output characteristic in a weak inverse state by using a MOS transistor by immediately obtaining the voltage signal corresponded to the light amount of the incident light even if a rapid change in a sensor current is occurred. SOLUTION: In the image sensor using the optical sensor circuit as the pixel converting the sensor current flowing through the photoelectric conversion element according to the incident light amount into the voltage signal with the logarithmic output characteristic in the weak inverse state by using the MOS transistor, a voltage switching circuit to discharge electric charges stored into parasitic capacitance of the conversion element before reading out pixel signals of each pixel, with changing drain voltages of the MOS transistor of each pixel into values lower than a usual value for a predetermined time is equipped.
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