| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a planar lighting device capable of suppressing generation of light/dark stripes. <P>SOLUTION: A plate light guide body 2 is formed with a light reflection pattern 29 comprising a stepped prism on its upper surface 15. The plate light guide body 2 is also formed with a reflection direction dispersion surface 21 along the axial direction of a light source part 5 similar to the light reflection pattern 29 on its lower surface 16. The reflection direction dispersion surface 21 is formed into, for example, an arc shape so as to continuously change the angle of a surface for reflecting the light. The reflection direction dispersion surface 21 can make lights (31a, 31b, and 31c) reflecting in the same angle direction in a step part 27 advance in the respectively different angle directions (32a, 32b, and 32c), make them mainly reach at gentle slope parts 28 (arrows 32a and 32b), and make them bent and irradiate to the outside (arrow 33). It can also make the light direction irradiated to the outside irregular. This constitution eliminate matching of the directions not receiving lights irradiated from the light reflection pattern in a certain region, thus suppressing the generation of the light/dark stripes. <P>COPYRIGHT: (C)2003,JPO |
