| 摘要 |
PURPOSE:To attain high luminance uniformity, thinning in thickness, and high luminance by providing a notch of slit shape at the inside of a fitting part between a light conductive plate and a light diffusion sheet or a light reflecting sheet. CONSTITUTION:A diffusion system 5 provided by performing printing or shape giving on the plane 3 opposite the light emitting plane of a transparent plate 1 is formed in thin line shape or dot shape on the plane 3 and has specified distribution for a mirror surface part. A light source 6 is arranged at one plane or confronting two planes of the end face 4 of the transparent plate 1, and a light beam from the light source 6 is introduced to the transparent plate 1. Several sheets of diffusion sheets 7 are piled on the side of a light emitting surface 2 of the plate 1. A light reflecting sheet 9 is arranged at the side of a plane 3 opposite the light emitting plane. One or plural notches 11 of slit shape are provided on the sheet 7 or sheet 9 between or in the neighborhood of two points of fitting parts 8 almost perpendicularly to the line connecting the two points. Therefore, it is possible to prevent the diffusion sheet 7 or the optical reflecting sheet 9 from being broken by decreasing a force in the direction almost perpendicular to the notch 11, i.e., a shearing force applied to the tip part of the notch 11. |
