| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve problems that, in a downright type lighting system using a curved fluorescent tube, although a curved part of the fluorescent tube is arranged outside an illumination face, light of the curved part of the fluorescent tube is not fully utilized for that very reason, and that a distribution of brightness on the illumination face needs to be satisfied while light utilization efficiency of the curved part of the fluorescent tube. <P>SOLUTION: Brightness unevenness inside the illumination face can be restrained and light irradiated from the fluorescent tube can be effectively utilized, by providing a prism sheet between a light transmission plate and the fluorescent tube so that its vertex angle is directed toward a direction of the fluorescent tube, and arranging the prism sheet so as to cover the curved part of the fluorescent tube. Further, by arranging the direction of ridge line of the prism of the prism sheet in parallel with an axis direction of the fluorescent tube, a refraction direction is to be at right angles with a light-emitting axis direction of the fluorescent tube, and the distribution of brightness can be made uniform. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
