Patent ID: 8277104

Claim:
A back-light unit comprising: a plurality of substrates; a plurality of light sources respectively disposed on the plurality of substrates and configured to emit light; and N light guide plates respectively disposed adjacent to the plurality of light sources, each light guide plate including a light incidence part having a light incidence surface for receiving light emitted in a first direction from a corresponding light source, and a light emission part for emitting the received incident light in a second direction different than the first direction, where N is greater than or equal to 2, wherein at least one of the light guide plates comprises light-extracting surface patterns disposed on the light emission part, wherein the light-extracting surface patterns comprise a first region of light-extracting surface patterns having a higher pattern-density than a second region of light-extracting surface patterns next to the first region and a third region of light-extracting surface patterns having a higher pattern-density than the second region of light-extracting surface patterns, and wherein the third region of light-extracting surface patterns is next to the second region of surface patterns.