Patent ID: 8408752

Claim:
A surface lighting unit plurally arranged in a matrix on a single plane, the unit comprising: a box-shaped casing having a footprint portion in which a hole for placing a highly directional point-light source is formed at the center thereof and sidewall portions standing from the footprint portion; and an optical reflector spaced apart by a certain distance from the footprint portion and having openings, wherein the surface lighting unit is used in such a manner that the point-light source is placed in the hole, inner surfaces of the footprint portion and of the sidewall portions, and an inner surface of the optical reflector that faces the footprint portion are reflective surfaces, the optical reflector has a center thereof facing the hole, the openings are so formed that an opening ratio represented by a ratio of the area of the openings in a preset region on the optical reflector to the area of the preset region increases as a distance from the center of the optical reflector increases outward, and the sidewall portions have sidewall holes formed to satisfy the opening ratio, and wherein the openings are formed in a non-through hole around the center of the optical reflector, in a plurality of non-continuous arcuate holes on the outer side of the non-through hole, and in a plurality of through holes on the outer side of the arcuate holes.