| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a flat lighting device that illuminates uniformly the whole screen using a point light source. <P>SOLUTION: A cross section of a light scattering means formed on the emitting surface side 12C of the light guide plate 12 is formed into triangular shape by the slanted surfaces 12E and 12F. The angles α1 of the triangle formed by the pair of slanted surfaces are identical with each other. Respective slanted surfaces 12E, 12 are formed into rough surfaces by a plurality of grooves B running in parallel with the slanted surfaces. Those grooves B are formed linearly in the direction parallel with the light incident from the above point light source. The direction of the light in the light guide plate 12 is changed by the rough surface having the plurality of grooves B formed on the slanted surfaces 12E, 12F so as to spread in lateral direction against the light emitted from an LED 7 incident in longitudinal direction of the slanted surfaces 12E, 12F when emitted from an emitting surface 12 and the light P1 spreading inside the light guide plate 12 is almost uniformly emitted from the light guide plate 12. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
