| 摘要 |
PROBLEM TO BE SOLVED: To provide a solid-state image pickup device without requiring a large voltage for resetting by which a low-noise and wide dynamic range can be obtained. SOLUTION: The voltage generating circuit 71 of a threshold voltage modulating system MOS type image sensor impresses a prescribed gate voltage VG and a prescribed drain voltage VD respectively to the gate 14 and the drain 16 of an MOS transistor 112 for detecting an optical signal. By this, a photocurrent Ip occurring in a photodiode 111 and a discharge current Isub discharged to a p-type substrate 11 are balanced with each other. A pixel 101 is set in a steady operating state in which the photocurrent Ip is steadily made to flow to the p-type substrate 11 via a p-type hole pocket 18 of a signal storage area. Channel potential of a channel 17 is read out from the source 15 of the MOS transistor 112 for detecting an optical signal in a state of holding the steady operating state. Consequently, an output signal Vout can be obtained by applying logarithmic conversion to the photocurrent Ip. COPYRIGHT: (C)2006,JPO&NCIPI
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