Patent ID: 8727594

Claim:
A display device, comprising: a display panel; and a backlight unit to be used as a planar light source for the display panel, wherein the backlight unit comprises: a light source having an emission region narrower than an emission region of the planar light source; and a light guide plate having an end surface into which light from the light source enters, and a front surface from which the light exits, wherein the end surface of the light guide plate comprises: a flat surface; and one of a protruding surface which protrudes with respect to the flat surface and a recessed surface which is recessed with respect to the flat surface, wherein light traveling from the light source in a direction perpendicular to the flat surface enters the light guide plate in an expanded manner due to refraction at the one of the protruding surface and the recessed surface, wherein the one of the protruding surface and the recessed surface has a shape in which a plurality of curved surfaces are integrated, the respective plurality of curved surfaces being formed about a plurality of central axes which are orthogonal to the front surface from which the light exits, wherein a pair of curved surfaces of the plurality of curved surfaces, which are positioned at both end portions of the one of the protruding surface and the recessed surface in an arraying direction of the plurality of curved surfaces, is each adjacent to the flat surface, wherein adjacent curved surfaces of the plurality of curved surfaces are connected to each other at a connection end point between the adjacent curved surfaces which is at a position shifted in one of a protruding direction and a recessed direction of the one of the protruding surface and the recessed surface with respect to the flat surface, and wherein, in a cross section taken along a plane parallel to the front surface from which the light exits, the plurality of curved surfaces represent a plurality of contiguous arcs, and the flat surface represents a straight line.