SURFACE LIGHT SOURCE DEVICE AND LIGHT GUIDE BODY USED FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a light guide body for a surface light source device of which generation of bright lines and dark lines in a light emission face area close to a light incident end face is prevented and of which uniformity of brightness of a whole of the light emission face is improved.

SOLUTION: A plate-shaped light guide body 4 guides light emitted from a primary light source 2 and has a light incident end face 41, a light emission face 43 and a rear face 44. On the light emission face 43, many minute projections are formed in areas 43-1 close to the incident end face 41, and the projections have an average height (H) of 7 to 13 μm, an average bottom area (S) of 500 to 1,100 μm2, an average distance (L) between any two nearest minute projections of 10 μm or longer, an aspect ratio (H/d) which is a ratio of the average height (H) to an average bottom vertical width (d) of 0.25 to 0.4 and an average distribution density (N) of 3×10-5to 11×10-5/μm2.

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