According to an embodiment of the present invention, a display device includes a backlight unit that is divided into a plurality of blocks and is driven by the divided blocks, and includes at least one optical assembly, a display panel positioned over the backlight unit, a controller that outputs local dimming values corresponding to brightness of the blocks of the backlight unit, in accordance with an image displayed in the display panel, and a BLU driver that controls brightness of the blocks of the backlight unit using the local dimming values.