| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a direct backlight device, in which periodical brightness variations at the light emitting face is suppressed and a high uniformity ratio of brightness is realized, while a high ratio of effective utilization of light flux is maintained by devising the constituting elements of the direct backlight device, and which hardly receives the influence from the environment. <P>SOLUTION: In the direct backlight device, constituted by a plurality of linear light sources 3 arranged in parallel, a reflecting plate 4 reflecting the light from the linear light source 3, a light diffusion board 2, and a diffusion sheet 1, arranged in the order of the reflecting plate 4, the linear light source 3, the light diffusion plate 2, and the diffusion sheet 1, the water absorbency of the light diffusion plate 2 is 0.10% or less, and at least one of the main faces of the light diffusion plate 2 has an indented structure with the maximum height Rz of 200 μm or less. <P>COPYRIGHT: (C)2007,JPO&INPIT |
