| 摘要 |
PROBLEM TO BE SOLVED: To reduce nonuniformity of luminance in the vicinity of an incident surface by forming the back surface of a plate-like member by an almost plane and a curved surface, gradually narrowing an interval between an emitting surface and the almost plane toward a surface opposed to an end surface from a tip end surface, and forming a width of the end surface in the shape of becoming narrow as an end surface of the curved surface becomes more distant from an effective light emitting area of a light source. SOLUTION: In a plate-like member, since a plate thickness becomes thin in a corner part in the vicinity of this incident surface, a large incident angle component is repeatedly reflected between the reverse 12B and an emitting surface to the emitting surface by that extent, and an incident angle to the emitting surface reduces every time when it is reflected by the reverse 12B. Therefore, a light scattering light conductive plate 12 suddenly reduces an incident angle of the illuminating light to the emitting surface in the corner part, and urges an emission of the illuminating light in the corner part by that extent, and a quantity of emitting light of the corner part increases. The illuminating light propagating on the central side of the light scattering light conductive plate 12 is distributed by scattering, and reduction in a luminance level on the wedge-shaped tip side can be avoided. |
