The present invention provides a display device. The display device includes: a backlight unit that is divided into a plurality of blocks and driven for each of the divided blocks and includes a plurality of optical assemblies; a display panel positioned on the top of the backlight unit; a controller that outputs a local dimming value for each of blocks corresponding to the blocks of the backlight unit depending on an image displayed in the display panel; and a BLU driver that controls the brightness of the blocks of the backlight unit by using the local dimming value for each block, wherein the optical assembly includes a substrate; a plurality of light sources that are positioned and emit light; and a light guide plate including a light input unit including an incident surface into which light is inputted through the side from the light source and a light emitting unit emitting the inputted light to the top, and wherein at least some portions of two adjacent optical assemblies among the plurality of optical assemblies are superimposed on each other, and the BLU driver receives the local dimming value for each block and outputs a plurality of driving signals and the blocks of the backlight unit are driven in the unit of the divided groups by being divided into a plurality of scan groups.