SIDE LIGHT TYPE SURFACE LIGHT SOURCE DEVICE

摘要

PROBLEM TO BE SOLVED: To make it possible to lessen the unequal luminance of exit light by projecting parts for positioning of a light transmission plate and to easily hold this light transmission plate by arranging these projecting parts on the light source side and flanks of the plate. SOLUTION: The light scattering and light transmission body 12 having a wedge-shaped sectional shape is constituted by adhering ink 16 as light shielding means to the upper and lower edges E of an incident surface 15 parallel with an exit surface. The light scattering light transmission body 12 is formed with the projecting parts 18 and 19 on its incident surface side and both flanks and is positioned and held to a frame by these projecting parts 18 and 19. The exit surface side is of the projection part 18 on a hot side is connected flatly to the exit surface and is formed to a triangular shape in sec. Further, the surface on the incident surface 15 side is firmed by a slope M1 in such a manner that the projecting part 18 parts from the incident surface 15 the farther from the exit surface 15. The projecting part 19 on a cold side is formed to the shape asymmetrical with the projecting part 18 by the shape formed by cutting a part of the projecting part 18 on the hot side.