Patent ID: 8411229

Claim:
A backlight unit comprising: a light guide plate; a light source at a side of the light guide plate; a flexible printed circuit board in which the light source is mounted, and a portion of which overlapping a portion of the light guide plate; an optical sheet on the light guide plate and including a plurality of sheets; and an extending portion extending from the optical sheet, wherein the extending portion overlaps the portion of the flexible printed circuit board, wherein the light guide plate includes a protruding portion at a region where light is incident, the protruding portion protruding in an upper direction from the light guide plate, wherein the light source is disposed at the incident region of the light guide plate, wherein the protruding portion is substantially the same thickness as the light source, wherein the flexible printed circuit board is disposed on the protruding portion of the light guide plate and the light source, wherein the extending portion is contacted on the portion of the flexible printed circuit board, wherein the extending portion extends from one sheet of the plurality of sheets, wherein the sheet having the extending portion is directly contacted with the light guide plate, wherein the extending portion extends from the light guide plate toward the light source, wherein the extending portion is overlapped with the edge of the portion of the flexible printed circuit board corresponding to the protruding portion of the light guide plate, wherein the width of the extending portion is the same as the width of the optical sheet, and wherein the length of the bottom sheet is longer than the length of the upper sheets.