A backlight unit includes a plurality of light emitting diode (LED) packages on a top surface of a circuit board, an encapsulation member located on the circuit board and covering the plurality of LED packages, and an integrated pattern sheet on the encapsulation member. The integrated pattern sheet includes a base layer, a plurality of reflective patterns at a bottom surface of the base layer and respectively corresponding to the plurality of LED packages, and a plurality of diffusion patterns at a top surface of the base layer, wherein the reflective patterns are configured with a relational expression of c+(t2−t1)*tan {(sin−1(1/n)}>d