Patent ID: 8379166

Claim:
A planar light-emitting device comprising: a plurality of light units each including a light source having a light-exiting surface and a lightguide member having an elongated shape, the lightguide member having an upper surface, a lower surface, and a peripheral side surface extending between the upper surface and the lower surface, the peripheral side surface having an end surface serving as a light-entrance surface disposed to face the light-exiting surface of the light source, an end surface opposed to the light-entrance surface, and two side surfaces extending between the light-entrance surface and the end surface opposed to the light-entrance surface, the lightguide member guiding light received from the light-exiting surface of the light source through the light-entrance surface toward the end surface opposed to the light-entrance surface and emitting the light from the upper surface and the side surfaces while guiding the light; and a reflecting member having a light-reflecting surface disposed to contact the lower surfaces of the light units; the plurality of light units being disposed in linear arrays each in which the light units are linearly disposed in series in an elongated direction of the lightguide member, the linear arrays extending in the elongated direction of the respective lightguide members, the linear arrays extending in parallel with each other and being spaced from each other in a width direction perpendicularly intersecting the elongated direction of the lightguide members, wherein the light-reflecting surface is quadrilateral in shape, one of the linear arrays being arranged along one diagonal line of the light-reflecting surface.