| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a direct backlight device having sufficient luminance in the front direction, and capable of suppressing luminance irregularity of a light emitting surface, and of reducing power consumption. <P>SOLUTION: In this direct backlight device having linear light sources 2, a reflector 3, and a light diffusion member 1, the distance (a) between the centers of the linear light sources 2 adjacent to each other is 30-65 mm. The light diffusion member 1 has a nearly-flat light entering surface 1A, and a light emitting surface 1B with a plurality of linear prisms 4 arranged side by side thereon. The linear prism 4 has two slant faces 4A having tilt angles generally equal to each other with respect to a plane vertical to the thickness direction of the light diffusion member 1. When it is assumed that a distance between the center position S of one of two images on the light emitting surface for one of the linear light sources, and a position R obtained by projecting the center of the linear light source to the light emitting surface is L (mm), a relationship of a/7<L<a/4 is satisfied. <P>COPYRIGHT: (C)2008,JPO&INPIT |
