Patent ID: 8330897

Claim:
A backlight unit comprising: an optical sheet; a receiving member configured to receive the optical sheet, the receiving member having a supporting surface supporting the optical sheet; an extension protruding from a side of the optical sheet; an inner surface position defining portion extending from the receiving member and facing a first side of the extension, the inner surface position defining portion being substantially perpendicular to the supporting surface of the receiving member; and an outer surface position defining portion extending from the receiving member and disposed apart from the inner surface position defining portion, the outer surface position defining portion facing a second side of the extension and being substantially perpendicular to the supporting surface of the receiving member, wherein a distance between the first and second sides of the extension is a width of the extension extending parallel to the side of the optical sheet, wherein a first distance between the inner surface position defining portion and the first side of the extension is less than a second distance between the outer surface position defining portion and the second side of the extension, and wherein a ratio of the second distance to the first distance is less than or equal to 6:1.