| 摘要 |
PURPOSE: To obtain a large and uniform light emission part in comparison with the area of the light emitting surface side of a light transmission body by using the light transmission plate provided with a projection part and densely forming the light diffusion elements on the surface of the light transmission plate close to a projection part in comparison with the vicinity of the periphery thereof. CONSTITUTION: At least one side of the side end parts of the light transmission plate 1 consisting of a light transmitting material is provided with a linear light source 4 near the plate 1. Besides, the light diffusion elements having a function diffusing the light are formed on one surface of the plate 1 so that the function thereof becomes larger as they are more distant from the light source 4. The light transmission plate 1 provided with one or more projection parts 7 is used and the light diffusion elements of the surface of the plate 1 set near the projection part 7 are densely formed at least in comparison with the vicinity of the periphery thereof. If is preferable that the area of a part(range 11) where the light diffusion elements are densely formed is appoximately made equivalent to 0.5-5 times as large as the area of one surface of the projection part 7. Besides, it is preferable that a degree for densely forming them is larger than the density of the vicinity of the periphery and within the range of 1.5 times as large as the density thereof. |
