SURFACE LIGHT SOURCE DEVICE AND LIQUID CRYSTAL DISPLAY

摘要

PROBLEM TO BE SOLVED: To provide a surface light source device which is excellent in the whiteness and softness of a bright surface and is free from mirroring and a liquid crystal display formed by using this surface light source device as a back light. SOLUTION: The end face on the thick side of a light scattering light transmission body 1 is formed as a light incident surface 2 and a fluorescent lamp L is arranged near this surface. A prism sheet 4' formed with prism surfaces on both surfaces is arranged on the outer side of a light having out surface 5. The orientation direction of the prism sheet 4' is so selected that the extension direction of the prism arrays 4a, 4b on the inner flank aligns to the crossing direction of the light scattering light transmission body 1 and the extension direction of prism arrays 4a, 4b on the outer flanks aligns to the longitudinal direction of the light scattering light transmission body 1. A reflector 3 is arranged on the rear surface 6 side of the light scattering light transmission body 1. The exit light from the light having out surface 5 is made into the light propagating in a front surface direction by the effect of the prism arrays 4a, 4b on the inner flank. This light is shifted in the crossing direction by the prism arrays 4c, 4d on the outer flank and is made into backward advancing light. The route history of the exit light from the prism sheet 4' is diversified and visual characteristics are improved.