Patent ID: 8669933

Claim:
A liquid crystal display panel comprising: a pair of substrates sandwiching a liquid crystal layer therebetween; an illumination unit for the liquid crystal display panel; a plurality of photodetectors that detect intensity of ambient light; a plurality of detection circuits each directly coupled to one of the plurality of photodetectors, each detection circuit including a different comparator; and a control unit for controlling brightness of the illumination unit for the liquid crystal display panel based on outputs from the detection circuits; wherein each of the detection circuits includes a circuit logically inverted when an output from the photodetector coupled to the detection circuit reaches a predetermined value, wherein the control unit includes a discrimination implement that determines the intensity of the ambient light has changed when outputs from half or more of the detection circuits are logically inverted, and wherein each of the photodetectors is a thin film transistor ambient light photosensor in which a time period taken to decrease to a predetermined voltage after a switching element in the photosensor has been turned off is inversely proportional to the intensity of the ambient light, and wherein the photodetectors and the detection circuits are both provided on the substrates included in the liquid crystal display panel.