Patent ID: 6999122

Claim:
An image-sensing apparatus comprising: a plurality of pixels, the pixels each including: a photodiode, having two electrodes, that produces an electric signal in accordance with amount of incident light; a first MOS transistor having a first electrode and a gate electrode connected to one electrode of the photodiode and a second electrode; and a second MOS transistor having a first electrode, a second electrode, and a gate electrode connected to the first and gate electrodes of the first MOS transistor; a third MOS transistor having a first electrode to which a direct-current voltage is applied, a second electrode, and a gate electrode connected to the second electrode of the second MOS transistor, the third MOS transistor amplifying a signal output from the second electrode of the second MOS transistor; a fourth MOS transistor having a first electrode connected to the second electrode of the third MOS transistor, a second electrode connected to an output signal line, and a gate electrode connected to a line select line; and a controller that makes the individual pixels perform image sensing in such a way that the electric signal output from the photodiode is converted natural-logarithmically by feeding a first voltage to the second electrode of the first MOS transistor so as to make the first MOS transistor operate in a subthreshold region below a threshold value thereof, wherein the controller resets the individual pixels by, in each pixel, feeding a second voltage to the second electrode of the first MOS transistor so as to permit a larger current to flow through the first MOS transistor than before feeding the second voltage thereto, and a capacitor having one end connected to the second electrode of the second MOS transistor, the capacitor being reset through the second MOS transistor when a reset voltage is fed to the first electrode of the second MOS transistor.