Patent ID: 8754978

Claim:
A semiconductor device including a pair of sensor units each of which includes a photoelectric conversion unit, a signal holding unit, and a transfer unit, and that outputs a signal corresponding to a signal held by said signal holding unit, comprising: a control unit including a detector unit, wherein said signal holding unit holds the signal corresponding to charges generated by said photoelectric conversion unit, said transfer unit transfers, to said signal holding unit, the signal corresponding to the charges generated by said photoelectric conversion unit in a conductive state, when one of said pair of sensor units operates in a first mode, the other operates in a second mode, after said transfer unit in the conductive state has started signal transfer in said sensor unit operating in the first mode, said detector unit detects that the signal output from said sensor unit has reached a predetermined value, said sensor unit operating in the first mode sets said transfer unit to a non-conductive state in response to the detection to end the signal transfer and thus determine the signal held by said signal holding unit, said control unit generates a control signal after an elapse of a predetermined time from the detection, and said sensor unit operating in the second mode sets said transfer unit of said sensor unit to the non-conductive state so as to accumulate the charges generated by said photoelectric conversion unit, sets said transfer unit of said sensor unit operating in the second mode in the conductive state in accordance with the control signal so as to start transfer of the signal corresponding to the generated charges, and then sets said transfer unit in the non-conductive state to end the signal transfer and thus determine the signal held by said signal holding unit.