In a predetermined period (one frame or one subframe), a backlight is lighted between the middle point in time in first data writing scanning and the middle point in time in second data writing scanning for each lighting region provided by dividing the backlight into four regions. When the time required for data writing scanning is set equal to 50% of the predetermined period, the ratio (panel on rate) of the time when a liquid crystal panel is in transmitting state to the time the backlight is lighted is as high as 93.8%. The ratio of luminance gradient (luminance in the center of display area/luminance at the end of display area) is as low as 1.14. When the backlight is lighted while being divided into ten regions, the panel on rate can be increased as high as 97.5% and the luminance gradient can be decreased as low as 1.05.
