| 摘要 |
PROBLEM TO BE SOLVED: To provide a planar lighting apparatus with high efficiency, high luminance, and yet having a high added value even if it is thin.SOLUTION: A planar lighting apparatus includes a light source and a light guide plate having an incident surface on which the light source is arranged and an emission surface from which light entering from the incident surface is emitted. Between the incident surface of the light guide plate and the light source, optical elements are provided which condense the light emitted from the light source by diffraction action in a short-length direction of the incident surface, and scatter the light by refraction action in a longitudinal direction of the incident surface. The optical element has a plurality of lattices of an elliptical annular shape arranged concentrically, and each of the lattices is formed so that dimensions in the longitudinal direction of the incident surface may be larger than those in the short-length direction of the incident surface. |
