THIN FILM TRANSISTOR, OPTICAL SENSOR CIRCUIT PROVIDED WITH THIN FILM TRANSISTOR, AND DISPLAY DEVICE

摘要

A thin film transistor (1) is to be used in a path wherein a current direction is fixed to one direction and provided with high-concentration impurity regions (3, 4) on the both sides of a channel region (5). The thin film transistor has a structure wherein a low-concentration impurity region (6) is sandwiched only between the high-concentration impurity region (3), which is on a side to which a carrier corresponding to the polarity of the high-concentration impurity regions (3, 4) flows in accordance with the direction of the current, and the channel region (5). Thus, the thin film transistor, which on/off controls output of an optical sensor incorporated in pixels constituting a display screen of a display device and has the structure not easily affected by a display signal, is provided.