Patent ID: 8803791

Claim:
A display device comprising an optical sensor in a pixel region on an active matrix substrate, wherein the optical sensor includes: a photodetecting element for receiving incident light; a reset signal line for supplying a reset signal to the optical sensor; a readout signal line for supplying a readout signal to the optical sensor; an accumulation node having a potential that varies with an amount of light received by the photodetecting element during a sensing period, the sensing period being a period from supply of the reset signal to supply of the readout signal; an amplifying element for amplifying the potential of the accumulation node according to the readout signal; and a sensor switching element for reading out the potential amplified by the amplifying element and outputting the potential as a sensor circuit output to an output line, wherein a light shielding film is provided on a side opposite to a light receiving surface side with respect to the photodetecting element, the light shielding film is connected to a power source for supplying a voltage for fixing a potential of the light shielding film to a constant potential, and the following formula is satisfied: V LS ≧V RST.H where V LS represents the constant potential and V RST.H represents a high level potential of the reset signal.