| 摘要 |
<P>PROBLEM TO BE SOLVED: To resolve the problem that a distribution of the quantity of light emitted from an entire surface part of a light guide plate is not uniform due to relative deficiency of the quantity of light emitted from a center part of the light guide plate in a planar lighting device having a pair of light sources disposed on both sides of the light guide plate. <P>SOLUTION: A light guide plate 11 includes a pair of incidence end face parts 12 and 13 to which light from light sources 14 and 15 is introduced, a front face part 18 from which the light introduced from the incidence end face parts 12 and 13 is emitted, a rear face part 25 placed on the opposite side of the front face part 18, and many light deflecting parts 20 formed in at least one of the front face part 18 and the rear face part 25. In this light guide plate 11, proportions of light deflecting parts 20 per unit area along a line from one incidence end face part 12 to the other 13 are set in two Gaussian distributions A and B, and a peak P<SB>A</SB>of the first Gaussian distribution A is located between one incidence end face part 12 and the center of the light guide plate 11 reaching the other incidence end face part 13 from one incidence end face part 12, and a peak P<SB>B</SB>of the second Gaussian distribution B is located between the other incidence end face part 13 and the center of the light guide plate 11. <P>COPYRIGHT: (C)2009,JPO&INPIT |
