SURFACE LIGHT SOURCE DEVICE, LIGHT GUIDE FOR SURFACE LIGHT SOURCE DEVICE AND METHOD FOR MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a light guide that does not lower brightness and does not impair even brightness over the entire surface and can obtain uniformity in brightness in a light outgoing surface near a light incident surface and a surface light source device using the same. SOLUTION: This light guide for a surface light source device has at least one side end surface as the light incident surface and the light outgoing surface crossing with it almost at a right angle, wherein a mean tilt angle of the light outgoing surface and its back surface and near at least one side surface of light incident surface is larger than the other parts.