| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a planar light source which is small in thickness and light in weight, and can emit illuminating light, more uniform and reduced uneven lighting, and higher brightness from a light emitting face with a high efficiency of using illuminating light. <P>SOLUTION: This planar light source includes a transparent and rectangular light guide plate 18, and the light guide plate 18 is formed as follows. A light emitting surface is formed on one surface of the light guide plate 18 which has at least either shape of convex or concave oriented nearly parallel to one side of the rectangular shape. A thick thickness portion is formed around the center of the rectangular light emitting surface oriented nearly parallel to the one side. A pair of thin thickness edge portions are formed nearly parallel to the thick thickness portion. A parallel groove for containing a rod-like light source is formed in the opposite side surface of the light emitting surface as to be oriented nearly parallel to the one side. A pair of rear slopping faces are formed on both sides of the parallel groove, respectively, and each of the rear slopping faces is formed as to reduce the thickness of the slopping rear face in a direction perpendicular to the one side from the thick thickness portion to the thin thickness edge portion. <P>COPYRIGHT: (C)2007,JPO&INPIT |
