Patent ID: 8120687

Claim:
A signal reading method for successively outputting a read signal by scanning a voltage value of an integrating capacitor in an image sensor in which a plurality of sensor parts are arranged in a two-dimensional array made up of rows and columns and each sensor part includes the integrating capacitor accumulating a charge obtained by integrating a photocurrent output from a sensor, said signal reading method comprising: carrying out a first integration of the photocurrent using the integrating capacitor and a first sampling and holding using a sample and hold capacitor in a first time interval, during a time of one frame made up of the first through third time intervals; carrying out a second integration of the photocurrent using the integrating capacitor in the second time interval, and carrying out processes in the first and second time intervals in common with respect to all of the sensor parts simultaneously; and starting a vertical scan by selecting the row in an order starting from a first row, resetting the sample and hold capacitor in a predetermined row from which the read signal is already output, carrying out a second sampling and holding using the sample and hold capacitor in the predetermined row, averaging a voltage across both terminals of the sample and hold capacitor in the selected row and a voltage across both terminals of the sample and hold capacitor in the predetermined row, and starting a horizontal scan by selecting the column starting from a first column, in the third time interval, in order to successively read a final output voltage with respect to the selected column.