The University of Tokyo

Furukawa Co., Ltd.

Yoshiyuki Usuki

Hiroyuki Takahashi

Kei Kamada

An electric signal produced by a photo-electric conversion element () is input to a comparator (). The comparator () judges whether the electric signal output from the amplifier () exceeds a reference voltage or not, and outputs a HIGH signal if 'exceeds'. A reference voltage modifier unit () elevates the reference voltage, after a predetermined time period elapses since the comparator () 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 (), 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.

Growing community of inventors

Ibaraki, Japan

Yoshiyuki Usuki