| 摘要 |
PROBLEM TO BE SOLVED: To provide a planar lighting device capable of reducing luminance unevenness thereof.SOLUTION: An optical element 34 on a light guide plate 12 is formed such that convex parts 36to 36are arranged in line repeatedly in the longitudinal direction of the optical element 34. A concave and convex shaped part 36 in which a hollow amount and/or a protrusion amount is not a fixed amount is formed by a three-dimensional curve surface constituting the convex parts 36to 36. Light made incident from an incident surface 12c of the light guide plate 12 is changed in optical path by the concave and convex shaped part 36 constituting the optical element 34 in a procedure in which the light made incident from light incident surface 12c of the light guide plate 12 proceeds through a light guide plate 12 inner part, and light is diffused. Moreover, the hollow amount and/or the protrusion amount is not a fixed amount, thereby, an optical path of light which proceeds through the light guide plate 12 inner part is changed at random and, therefore, diffusion effect of light is efficiently exhibited. |
