DIRECTIONAL LIGHT GUIDE PLATE AND METHOD FOR WORKING LIGHT INCIDENT END SURFACE OF DIRECTIONAL LIGHT GUIDE PLATE

摘要

PROBLEM TO BE SOLVED: To provide a directional light guide plate and a method for working the light incident end surface of the light guide plate by which a surface light source for a large screen having uniform and high luminance is realized. SOLUTION: In the directional light guide plate (A) wherein light made incident from the end surface is exited from either surface of the upper surface or the rear side surface and also a grain pattern consisting of innumerable fine projecting and recessing parts is provided in the light exiting side, the light incident end surface (a1) is roughened by a stripe pattern (1) consisting of vertical stripes (11) along the thickness direction.