Patent ID: 7658529

Claim:
A surface light source device which illuminates a transmission-type liquid crystal display unit from a back surface, the liquid crystal display unit having a display area including pixels arranged in a two-dimensional matrix, the surface light source device comprising: P×Q surface light source units corresponding to P×Q imaginary display area units obtained by assuming that the display area of the liquid crystal display unit is divided into the P×Q imaginary display area units, wherein light sources included in the surface light source units are individually controlled, a light source included in each of the surface light source units includes a plurality of light-emitting element units, each of the light-emitting element units includes at least one red light-emitting element that emits red light, at least one green light-emitting element that emits green light, and at least one blue light-emitting element that emits blue light, the center of mass of a luminance profile based on a plurality of red light-emitting elements in each of the surface light source units substantially coincides with the center of mass of the surface light source unit, the center of mass of a luminance profile based on a plurality of green light-emitting elements in each of the surface light source units substantially coincides with the center of mass of the surface light source unit, and the center of mass of a luminance profile based on a plurality of blue light-emitting elements in each of the surface light source units substantially coincides with the center of mass of the surface light source unit.