Light identifying system.

摘要

A light identifying system, comprising: a photoelectric conversion unit (14) for receiving a light from a light emitting part (11) on a light receiving part (12), and generating a light reception signal in magnitude according to a quantity of the received light; a peak holding circuit (19) having a time constant large enough as compared with a lighting time interval of said light emitting part (11), and holding a peak value of said light reception signal inputted therefrom on said time constant; a comparator (21) for inputting the peak value held by the peak holding circuit (19), and comparing it with said light reception signal as a threshold.