Thin film phototransistor, active matrix substrate using the phototransistor, and image scanning device using the substrate

摘要

A gate insulation film ( 14 ) and a semiconductor layer ( 15 ) are laminated on a gate electrode ( 13 ); and a source electrode ( 17 ) and a drain electrode ( 18 ) are formed on the semiconductor layer ( 15 ) by having a predetermined interval between their end portions. Each of the source electrode ( 17 ) and the drain electrode ( 18 ) includes a superimposition area ( 17 a and 18 a), and at least one portion of the superimposition area ( 17 a and 18 a) has translucency. This arrangement realizes improvement of photosensitivity (Ip/Id) without causing complication of wiring layout or manufacturing process.