Liquid crystal display, electronic device, and method for controlling brightness of illumination unit of liquid crystal display

Abstract

A liquid crystal display according to an embodiment of the present invention includes a liquid crystal display panel, an illumination unit for the liquid crystal display panel, a plurality of photodetectors, and a control unit Cnt to control the brightness of the illumination unit. The photodetectors are TFT ambient light photosensors LSto LS, for example, which produce outputs that require time to reach a predetermined value, which the time is correlated with the intensity of ambient light. Detection circuits coupled to the photodetectors include circuits (Cmpto Cmp) logically inverted when an output from the TFT ambient light photosensors LSto LSreaches a predetermined value. The control unit Cnt includes a discrimination implement Maj that determines that the intensity of ambient light has changed when outputs from the majority of the detection circuits are logically inverted. The above-mentioned structure provides a liquid crystal display that does not use plurality of interface circuits nor A/D converters, nor experience frequent malfunctions for automatic control of the brightness of the illumination unit according to the intensity of ambient light.