Patent attributes
A liquid crystal display device of the invention has: a display panel with an active matrix substrate 2 and a second substrate of transparent material deposed opposite that substrate; an illuminating unit that illuminates the display panel; and a photosensing unit that is provided on the active matrix substrate and has an ambient light photosensor that senses external light. The ambient light photosensor is constituted of a thin film transistor. At least the source electrode SL and drain electrode DL of the thin film transistor are covered by a shielding transparent electrode 6, with transparent insulator 3 and 5 interposed. The transparent electrode 6 is electrically connected to the drain electrode DL, and moreover is connected to a power source supplying constant voltage. Thanks to such structure, a display device is provided in which the ambient light photosensor is built into a panel substrate so as not to be affected by external noise and the peripheral circuits.
