| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface light source device capable of improving light brightness coming out from a light emitting surface of a light guiding plate, i.e., luminance even in a case using the same light source as conventional one while removing a part being not effectively reflected by a reflector of light emitted from a light source arranged along the side end face of the light guiding plate. SOLUTION: In this device 10, a light source 12 arranged at the side end part of a light transmission plate 11, in which one surface is made a light emitting surface 11b and a light incident scattering reflection means is provided, and the light source 12 covered with a reflector 13 so that light emitted from the light source 12 is entered to inside of the light transmission plate 11 from an end face of a side end part. Where, the reflector 13 is provided with at least one parallel light reflection step 15 formed on a miller face part of the reflector 13 so as to reflect light from the light source 12, which is emitted from within a certain angle range centering a virtual axis line 14 being nearly parallel with the light emitting surface normal line 17 of the light transmission plate 11 with passing through the center of the light source 12, in a direction avoiding the light source 12. |
