| 摘要 |
PROBLEM TO BE SOLVED: To provide an image sensor of a wide dynamic range warranted at all times capable of obtaining a logarithmic output characteristic without affected by the wiring resistance of a power supply system independently of an installed location of an optical sensor circuit of the image sensor so as to prevent the logarithmic output characteristic from being lost even when an incident luminous quantity is less. SOLUTION: The image sensor including optical sensor circuits in the unit of pixels for outputting a sensor signal with a logarithmic characteristic in a weak inverting state utilizing a characteristic of a sub threshold region of a transistor from a sensor current flowing to a photoelectric conversion element in response to the incident luminous quantity at photographing and selecting a drain voltage of the transistor to be lower than a steady-state value to initialize the optical sensor circuits prior to photographing, is provided with a means for gradually restoring the drain voltage of the transistor to a steady-state value at a rate at which a gate voltage is unchanged by a gate-drain coupling capacitance of the transistor after the initialization. COPYRIGHT: (C)2004,JPO
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