US Patent 7339672 Solid-state image pickup device and signal reading method therefor

A solid-state image pickup device has a photoelectric conversion part performing photoelectric conversion on incident light, a comparison part connected to an output terminal of the photoelectric conversion part to compare an output voltage of the photoelectric conversion part with a reference voltage, a capacitive element having one end connected to the output terminal of the photoelectric conversion part, and a control line connected to the other end of the capacitive element. In a signal storage period, a first control voltage is applied to the control line so as to make an electric potential at the output terminal of the photoelectric conversion part fall outside a transition region of the comparator. In a signal read period, a second control voltage is applied to the control line so as to make the electric potential at the output terminal of the photoelectric conversion part fall within the transition region of the comparator.