Patent ID: 8212967

Claim:
A backlight unit, comprising: a cover bottom having a plurality of light source groups each with a plurality of light sources thereon, a supplementary light source group formed between the light source groups adjacent to each other for reducing a difference in brightness between the light source groups adjacent to each other, wherein the light sources with the higher brightness are arranged in the light source group closer to a center portion of the cover bottom, and the light sources with the lower brightness are arranged in the light source group closer to a periphery of the cover bottom, wherein the light source groups are on the cover bottom to surround the center portion of the cover bottom, and distances from the center portion of the cover bottom to the light source groups are different from one another, respectively, wherein the supplementary light source group includes two kinds of supplementary light sources having brightness different from each other, wherein the brightness of one kind of the supplementary light sources in the supplementary light source group is the same with the brightness of the light sources in one of the two light source groups adjacent to each other, and the brightness of the other kind of the supplementary light sources in the supplementary light source group is the same with the brightness of the light sources in the other one of the two light source groups adjacent to each other, wherein the two kinds of supplementary light sources in the supplementary light source group are arranged alternately.