| 摘要 |
PROBLEM TO BE SOLVED: To prevent logarithm output characteristics from being lost by a change in a gate voltage according to the coupling capacity between a gate and a drain when returning the drain voltage of a transistor for logarithm characteristic conversion, in a photosensor circuit that becomes a pixel unit in an image sensor to a steady voltage after completing initialization. SOLUTION: In the image sensor, a sensor current flowing in a photoelectric conversion element according to the quantity of incident light in photography allows a sensor signal to be outputted by logarithm characteristics in a weakly inverted state utilizing the characteristics of the sub threshold region in the transistor. At the same time, in the image sensor, the photosensor circuit where the drain voltage of the transistor is changed to a valve being lower than a steady value for initializing prior to the photography is used as a pixel unit. In this case, wiring in a drain power supply of the transistor for the logarithm characteristic conversion in each pixel is allowed to orthogonally cross wiring in a gate power supply. COPYRIGHT: (C)2004,JPO
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