The deterioration (darkness) of image quality due to a reduction in the brightness of a single color as a result of the conversion from RGB pixels to RGBW pixels is prevented and a reduction in the power is achieved. A processing portion for conversion from RGB to RGBW 106 is formed of a W generating circuit 201, which is the same as in the prior art, a sub-pixel rendering circuit 202, a W intensity calculating portion 203 which transmits a W intensity setting value 205 to a W generating circuit 201, and a low power backlight control circuit 204 which expands data on the basis of the RGBW pixels generated by the sub-pixel rendering portion 202 and lowers the backlight in accordance with the amount by which the data is expanded. The inputted RGB data is used as the RGBW data with the W intensity calculated by the W intensity calculating portion 203. A backlight control signal is generated in accordance with the amount of data expansion in the sub-pixel rendering portion 202.