Image reading device having a conductive layer formed below a light receiving window

摘要

A photosensor having an electrically insulating, translucent substrate; an opaque conductive layer formed on the substrate; and insulating layer formed on the conductive layer, and a semiconductive layer formed on the insulating layer for receiving light and providing a current corresponding thereto. A pair of electrodes are formed in contact with the semiconductor layer and define a light receiving window therebetween. The electrodes are formed so as to not substantially overlap the conductive layer. The conductive layer is supplied with a bias voltage corresponding to a polarity and an amount of carriers defining the current of the semiconductor layer and a voltage Va of a small absolute value during a non-reading period of the photosensor.