| 摘要 |
PROBLEM TO BE SOLVED: To compensate fluctuation in characteristics based on variation in the threshold voltage of transistors to constitute a source follower for outputting a signal. SOLUTION: This image sensor is provided with coupling capacity 202 on which outputted voltage of a pixel is impressed via a transistor 201 and a transistor 203 of a source follower to read the voltage of a node S/Hn at the output side of the coupling capacity 202. Then, after a drain of the transistor 203 is made to a power supply voltage, a transistor 205 is turned on an the node S/Hn is pre-charged to the power supply voltage, a transistor 206 is turned on, the node S/Hn is clamped to the sum of a constant voltage and a threshold value of the transistor 203, the transistor 201 is turned on and the outputted voltage when the pixel is exposed is impressed on the capacity 202. Then, the drain of the transistor 203 is returned to the power supply voltage, the transistor 201 is turned on again and the outputted voltage when the pixel is unexposed is impressed on the capacity 202.
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