LIQUID CRYSTAL DISPLAY DEVICE, ELECTRONIC EQUIPMENT, AND METHOD OF CONTROLLING LIGHTNESS OF ILLUMINATION MEANS IN LIQUID CRYSTAL DISPLAY

摘要

PROBLEM TO BE SOLVED: To provide a liquid crystal display device allowing control by reducing malfunction, without using a plurality of interface circuits, A/D converters or the like, when controlling automatically the lightness of an illumination means in response to the intensity of environmental light.;SOLUTION: The liquid crystal display device includes a liquid crystal display panel, the illumination means for the liquid crystal display panel, a plurality of photodetectors, and a control means Cnt for controlling the lightness of the illumination means. The photodetectors are, for example, TFT photosensors LS₁-LS₃ having a correlation between a time period until outputs from the photodetectors get to a prescribed value and the intensity of the environmental light. Detecting circuits includes circuits Cmp₁-Cmp₃ logically inverted when outputs from the TFT photosensors LS₁-LS₃ get to a predetermined prescribed value. The control means Cnt has a determination means Maj for determining that the intensity of the environmental light is changed, when a half or more of outputs from the plurality of detecting circuits are logically inverted.;COPYRIGHT: (C)2009,JPO&INPIT