SIGNAL LIGHT DETECTION DEVICE AND METHOD

摘要

An electric signal produced by a photo-electric conversion element(104) is input to a comparator (120). The comparator (120) judges whether the electric signal output from the amplifier (110) exceeds a reference voltage or not, and outputs a HIGH signal if "exceeds". A reference voltage modifier unit (130) elevates the reference voltage, after a predetermined time period elapses since the comparator (120) judged that the electric signal reached or exceeded the reference voltage. The signal processor calculates an incidence time which represents a time when the signal light starts to enter the photo-electric converter unit (100), by correcting a rise-up time of the electric signal when it reaches or exceeds the reference voltage, based on a pulse width which represents a time period from when the electric signal exceeds the reference voltage, up to when the electric signal falls below the reference voltage.