Patent ID: 8427463

Claim:
A liquid crystal display device comprising: an active matrix substrate on which a plurality of sets of active elements and pixel electrodes are placed in a matrix, a counter substrate on which a counter electrode is placed, and a liquid crystal layer interposed between the two substrates, and the display device adapted for inversion driving in which a polarity of a voltage applied to the liquid crystal layer is inverted for each predetermined period, a photodetection part provided on the active matrix substrate for each of at least two of the active elements, and a drive part, wherein the photodetection part includes a photodiode that receives light incident through the counter substrate and the liquid crystal layer and outputs an electric signal in accordance with an amount of the received light, and a capacitance that stores charge in accordance with the electric signal, and outputs a photodetective signal whose level changes in accordance with an amount of the stored charge, and the drive part outputs, to each photodetection part, a reset signal that resets the charge stored in the capacitance and a reading signal that causes the photodetection part to output the photodetective signal during a period in which the polarity is set to be a predetermined one, wherein the reset signal and reading signal are output by the drive part during a time period which is (i) after inversion of the polarity occurs, and (ii) prior to video data being output to a corresponding active element for display before another inversion.