Semiconductor photosensor and driving method therefor

摘要

A photosensing system is described. Light rays to be sensed is incident on a photosensitive semiconductor device which allows much current to pass therethrough during receiving the incident light and which passes a little current when there is no incident light. The current passing through the semiconductor device is accumulated in a suitable storage means. The accumulated charge is detected, in order to judge the existence or the absence of the incident light, a certain time period after the pulsed signal is outputted.