Patent ID: 6958775

Claim:
A photo-sensor circuit comprising a photo-detecting element, a first MOS transistor for charging and discharging a parasitic capacitance of the photo-detecting element, a capacitor for accumulating a terminal voltage of the photo-detecting element as a pixel signal, a second MOS transistor for transferring a parasitic capacitance electric charge from the photo-detecting element to the capacitor, a third MOS transistor for amplifying the terminal voltage of the capacitor, and a fourth MOS transistor for selectively outputting an amplified pixel signal, characterized in that the first MOS transistor and the second MOS transistor are turned ON for a certain period of time before accumulation of a pixel signal to equalize terminal voltages of the photo-detecting element and the capacitor by charging/discharging the parasitic capacitance of the photo-detecting element and the capacitor, the second MOS transistor is turned OFF and the capacitor is open after a certain period of time of accumulation of the pixel signal and then the fourth MOS transistor is switched ON.