Patent ID: 8767137

Claim:
A liquid crystal display device comprising: a light source which generates an irradiation light; and a liquid crystal panel which includes a liquid crystal layer which is sandwiched between a pair of substrates, the liquid crystal panel being provided pixels, each consisting of red, green and blue subpixels, and controlling a transmission of the irradiation light; wherein the irradiation light is generated from emission of phosphors of a fluorescent lamp as the light source; an aperture ratio of the green subpixel in the each pixel of the liquid crystal panel is fixed to a desired value in advance; aperture ratios of the red subpixel and the blue subpixel in the each pixel of the liquid crystal panel are determined such that, in a state where the aperture ratio of the green subpixel is fixed to the desired value, white brightness efficiency takes a maximum value which is set based on a balance between light emission efficiency which is increased corresponding to lowering of a color temperature of the light source and transmissivity of the pixel which is decreased corresponding to an increase of the aperture ratio of the blue subpixel; the liquid crystal display device is an active-matrix-drive type liquid crystal display device in which each subpixel includes a thin film transistor which connects an individual electrode arranged in the subpixel to a signal line in response to a control voltage applied to a gate of the thin film transistor from a scanning line; a ratio among areas of the individual electrodes of the red subpixel, the green subpixel and the blue subpixel in each pixel is set to a value corresponding to a ratio among the aperture ratios of the red subpixel, the green subpixel and the blue subpixel in each pixel; and a size of the thin film transistor which is defined by a ratio W/L between a gate width W and a gate length L is set such that the ratio W/L of the size of the thin film transistor among the red subpixel, the green subpixel and the blue subpixel takes a value corresponding to the ratio among the aperture ratios.