LIGHT TRANSMISSION BODY, SURFACE LIGHT SOURCE DEVICE AND FRONT LIGHT DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE EMPLOYING THE LIGHT TRANSMISSION BODY

摘要

PROBLEM TO BE SOLVED: To provide a surface light source device and a front light device each of which has high illumination efficiency while keeping proportionality in a picture, a small number of members, excellent assemblability and is low-cost and also to provide a light transmission body to be used for them and a liquid crystal display device employing it. SOLUTION: A material with 0%-35% haze in 1 mm thickness based on ASTM D1003 is used for the light transmission body 11 where at least one side end part 11a is adopted as a light incident surface and one front surface is as a light emitting surface 11b. A light extracting mechanism 170 which is constituted of many recessions 17 consisting of a flat and smooth surface on the opposing surface 11c of the light emitting surface 11b of the light transmission body 11 in order to uniformize an outgoing light amount on the light emitting surface 11b. A dome shape is adopted in the cross section of each recession 17 in a direction 21 for mainly propagating a light beam and also the selection ratio of the outgoing light amount in the direction of the normal 14 of the light emitting surface 11b in the light transmission body 11 is within the range of 65%-100%.