Backlight unit for liquid crystal display device module

PURPOSE: A backlight unit for liquid crystal display device is provided to be divided into a plurality of domains. CONSTITUTION: A light guide plate is settled on the top of reflector. The light guide plate comprises a plurality of grooves. A plurality of LEDs is arranged to a first and a second LED(Light Emitting Diodes) assemblies(130,140) according to a light receiving surface of light guide plate. A first and a second LED assembly drive by dividing a plurality of areas. A plurality of optical sheets is settled on the light guide plate.