Solid state imaging device and method of driving the same

A method of driving a solid state imaging device, the device including:

• an accumulation well that accumulates photo generated electric charges generated by a photoelectric conversion element corresponding to incident light;
• a modulation well that controls a threshold voltage of a channel of a modulation transistor by storing the photo-generated electric charges;
• a residual electric charge discharging control element that controls a potential barrier of a residual electric charge discharging channel coupled to the modulation well;
• a reading means for driving the modulation transistor and the residual electric charge discharging control element, and carrying out mutually different controls with respect to a cell where a reading is carried out, and to a cell where a reading is not carried out, in a modulation period that a signal modulation output based on the photo-generated electric charges accumulated in the modulation well, and a noise modulation output based on a noise component are obtained;
• a clear means for driving the modulation transistor and the residual electric charge discharging control element, and carrying out mutually different controls to a cell where a clear is carried out and to a cell where a clear is not carried out in a clear period that, residual electric charges remaining in the modulation well are discharged;
• the method comprising:
• a dummy clear step for carrying out a control for a cell where the clear is not carried out by the clear means, to all the cells, before reading the first line from a pixel region;
• and
• a reading step including a signal modulation by the reading means, a clear by the clear means, and a noise modulation by the reading means.

A solid state imaging device, comprising:

• a pixel region having a cell in a matrix form the cell including:
• a photoelectric conversion element generating photo-generated electric charges corresponding to incident light;
• an accumulation well accumulating the photo-generated electric charges;
• a modulation well storing the photo-generated electric charges transferred from the accumulation well;
• a modulation transistor having a threshold voltage of a channel controlled by the photo-generated electric charges stored in the modulation well and outputting a pixel signal corresponding to the photo-generated electric charges;
• and
• a residual electric charge discharging control element controlling a potential barrier of a residual electric charge discharging channel coupled to the modulation well and discharging the residual electric charges in the modulation well through the residual electric charge discharging channel;
• a reader that drives the modulation transistor and the residual electric charge discharging control element, and carries out different controls to a cell where reading is carried out, and to a cell where reading is not carried out, in a modulation period when a signal modulation output based on the photo-generated electric charges accumulated in the modulation well, and a noise modulation output based on a noise component are obtained;
• a clearer that drives the modulation transistor and the residual electric charge discharging control element, and carries out different controls to a cell where a clear is carried out, and to a cell where a clear is not carried out, in a clear period when residual electric charges in the modulation well are discharged;
• and
• a dummy clearer that controls the clearer, and carries out a control for a cell where the clear is not carried out by the clearer, to all the cells, before reading a first line from a pixel region.