Surface light source device and liquid crystal display unit

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 partitioned from one another by partition walls,
• wherein
• each of the surfaces of the partition walls diffuse reflected light or specularly reflect light;
• light sources included in the surface light source units are individually controlled, and
• a light source included in each of the surface light source units includes a light-emitting circuit, the light-emitting circuit comprising at least one light-emitting unit, each of the at least one light-emitting unit being positioned in an area of the light source such that the light-emitting circuit is arranged to emit white light of a uniform color for an entirety of the surface light source unit, the at least one light-emitting unit being positioned such that a center of mass of the luminance profile for the at least one light-emitting unit coincides with a center of mass of an area defined by the partition walls of the surface light source unit such that the at least one light-emitting unit is configured to emit white light of a uniform color for an entirety of the surface light source unit.

A transmission-type liquid crystal display unit which has a display area including pixels arranged in a two-dimensional matrix, comprising a surface light source device that illuminates the liquid crystal display unit from a back surface,

• wherein:
• the surface light source device includes 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;
• light sources included in the surface light source units are individually controlled and are configured to emit white light;
• the P×Q surface light source units comprise at least one first surface light source unit and each of the at least one first surface light source units includes first light sources,
• the white light emitted by the first light sources of each of the at least one first surface light source units has a luminance profile, and
• for each luminance profile of the white light emitted by the first light sources of each of the at least one first surface light source unit, a center of mass of that luminance profile is located inside a circle of diameter D drawn around a center of mass of a corresponding first surface light source unit of the at least one first surface light source unit, such that the first light sources of that corresponding first surface light source unit are configured to emit white light for an entirety of the surface light source unit, where D is determined by the equation D=0.2 S01/2 and S0 is a surface area of that corresponding first surface light source unit.