Patent ID: 8199281

Claim:
A backlight applying transmissive light to a transmission-type liquid crystal panel provided in a liquid crystal display device, a screen of said liquid crystal panel having a plurality of regions, said backlight comprising: a plurality of light emitting sources provided corresponding to said plurality of regions, respectively; a plurality of edge-light type light guide plates provided corresponding to said plurality of regions, respectively, each edge-light type light guide plate having a surface facing a corresponding one of the regions, having an end face on which light is incident from a corresponding one of the light emitting sources, and causing the light incident on the end face to emit from the surface; a brightness control unit for obtaining a brightness of an image displayed on each of the regions based on an image signal and, based on the brightness, controlling a brightness of each of the light emitting sources corresponding to respective regions, wherein: said plurality of regions are arranged in a plurality of rows and a plurality of columns, said plurality of edge-light type light guide plates are provided corresponding to said plurality of regions, respectively, and arranged in said plurality of rows and said plurality of columns, each of a plurality emitting sources in of the plurality of columns is placed on one side of a corresponding one of the plurality of edge-light type light guide plates; and a plurality of substrates provided corresponding to said plurality of columns, respectively, each substrate having the plurality of light emitting sources on a corresponding one of said plurality of columns; each region comprises a rectangular shape, each edge-light type light guide plate comprises a rectangular shape, a recess is provided at an intersection of the end face on one side and an undersurface of each edge-light type light guide plate, a reflection surface facing the surface and the end face on the one side of each edge-light type light guide plate is provided at the intersection of an end face on the other side and the undersurface of the edge-light type light guide plate, the reflection surface of each edge-light type light guide plate intersects each of the surface and the undersurface of the edge-light type light guide plate, the plurality of light emitting sources are housed in a plurality of the recesses, respectively, each light emitting source emits light into the corresponding edge-light type light guide plate, and the light of each of the plurality of light emitting sources incoming into the edge-light type light guide plate is reflected and diffused by the undersurface and the reflection surface of the edge-light type light guide plate and emitted from the surface of the edge-light type light guide plate.