OPTICAL POSITION DETECTOR AND RANGEFINDER

A signal current I1 that is output from output terminal of semiconductor position detection element is converted to a signal voltage V1 by a current/voltage conversion unit and a signal current I2 that is output from output terminal is converted to a signal voltage V2 by a current/voltage conversion unit. Signal voltages V1 and V2 are compared in magnitude by a comparison circuit and a comparison signal is output so that maximum signal Vmax and minimum signal Vmin are selected. In A/D conversion circuit, the A/D conversion range is set using maximum signal Vmax, and minimum signal Vmin is converted to a digital signal and output. The position of beam incidence on semiconductor position detection element is found by incidence position calculating unit using the comparison signal and digital signal.