| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light guide plate capable of efficiently extracting light from an emission face, and a planar light source device as well as a transmission image display device including the same. <P>SOLUTION: The light guide plate 40 is provided with an emission face 41 for emitting light, a rear face 42 opposed to the emission face, and an incident face 43 crossing the emission face as well as the rear face for light from the light source 50 to be incident into. The incident face takes on a concave shape recessed toward an inside of the plate against a first virtual plane P1 connecting an incident face side end part each of the emission face and the rear face, and provided, an angle made by at least either region in the incident face at an end part 43b side of an emission face side or a rear face side and the first virtual plane is α, a refraction index of a surface layer at an emission face side of the light guide plate is n<SB POS="POST">1</SB>, and a refraction index at a further rear face side than the surface layer in a thickness direction of the light guide plate is n<SB POS="POST">2</SB>, α is an angle satisfying formula (1). <P>COPYRIGHT: (C)2013,JPO&INPIT |
