| 摘要 |
PROBLEM TO BE SOLVED: To improve the utilization efficiency of illumination light and to emit high- grade illumination light by repetitively forming projecting parts on the exit surface of a planar member or the rear surface facing this exit surface and smoothly forming these projecting parts according to the positions on the exit surface or the rear surface. SOLUTION: The very small projecting parts are repetitively formed on the exit surface 12c of the light scattering light transmission plate 12 as shown by an arrow (c) expanding an incident surface 12A side in a direction parallel with the incident surface. The very small projecting parts are so formed by working of metal molds for molding the light guide plate 12 in such a manner that the projecting parts are made successively smoother by the expansion of the radii of the curved surfaces connecting slopes 12E, 12F the nearer the flank side. In addition, the projecting parts are made successively smoother the nearer the incident surface from the front ends of the wedge shapes. As a result, the illumination light emitted to spread outward within the plane parallel with the incident surface 12A is corrected of the directivity so as to face inward and is emitted by the slopes 12E, 12F of the projecting parts repetitively formed in parallel with the incident surface. Then, the directivity of the exit light is corrected in the front surface direction of the exit surface 12c. |
