| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light guide forming a planar light source which prevents generation of sticking between a light emitting surface range closer to a light incident end face of the light guide and a light-polarizing element and is excellent on a luminance well-balanced degree even though a primary light source of an LED is used and the light guide and the light-polarizing element are thinned. <P>SOLUTION: The light guide 4 has the light incident end face 41 where light emitted from the LED 2 is incident, an opposite end face 42, and a light emitting surface 43 made of a rough surface where guided light is emitted. An average inclined angle of the light emitting surface 43 is 0.1-1 ° at a first boundary range 431 adjacent to a boundary of the light incident end face, and is gradually increased toward a second boundary range 432 adjacent to a boundary of the opposite end face from the first boundary range 431, and is greater than the first boundary range 431 at 1° or more in the second boundary range 432. Ten-point average roughness of the light emitting surface 43 is 0.7 μm or more at a light incident side-beltlike range 433 including the first boundary range 431 and a range adjacent to the first boundary range 431 and extending along the light incident end face 41. <P>COPYRIGHT: (C)2010,JPO&INPIT |
