Patent ID: 7285764

Claim:
A solid state imaging device, comprising: a substrate; a photoelectric conversion element in the substrate that generates photo-generated electric charges corresponding to incident light; an accumulation well that accumulates the photo-generated electric charges; a modulation well that stores the photo-generated electric charges transferred from the accumulation well; a modulation transistor having a channel threshold voltage that is controlled by the photo-generated electric charges stored in the modulation well and that outputs a pixel signal corresponding to the photo-generated electric charges; a transfer control element having a control end that is integrated with a control end of the modulation transistor and that changes a potential barrier of a transfer channel between the accumulation well and the modulation well, and controls transfer of the photo-generated electric charges, wherein the control end of the transfer control element and the modulation transistor correspond to a single ring transfer gate that is controlled by a single driving voltage supplied by a common drive circuit; an unwanted electric charge discharging control element that controls the potential barrier of an unwanted electric charge discharging channel coupled to the accumulation well, wherein the unwanted electric charge discharging control element discharges the photo-generated electric charges that overflow from the accumulation well through the unwanted electric charge discharging channel during a period except a transfer period of the photo-generated electric charges from the accumulation well to the modulation well by the transfer control element; and a residual electric charge discharging control element that controls the potential barrier of the residual electric charge discharging channel coupled to the modulation well, and discharges the residual electric charges in the modulation well through the residual electric charge discharging channel.