| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light guide plate having a simple structure, thin, and light in weight, and capable of emitting an illumination light having a high utilization rate of light and uniform and high luminance with little unevenness, from the light-emitting face, a planar lighting device, and a liquid crystal device. <P>SOLUTION: The light guide plate has a rectangular light-emitting face 18a, a thick portion 18b which is nearly parallel to its one side and is located at its central part, a pair of thin end portions 18c formed in nearly parallel to the thick portion 18b, parallel grooves 18f formed at nearly a center of the thick portion and at the reverse side to the light-emitting face and housing a rod-shape light source 12, and a pair of inclined back-face portions 18e which become thin from the thick portion 18b toward the thin portion 18c on both sides and form a pair of inclined back faces respectively on both sides of the parallel grooves 18f. The parallel grooves 18f are constructed of a pair of contour lines which become narrower toward the light-emitting face 18a and cross each other at the top-most vertex in cross-section in right angle directions, and each contour line is formed so as to become a more acute angle at the farther base end side from the vertex than the top end side near the vertex. <P>COPYRIGHT: (C)2007,JPO&INPIT |
