Light guide plate, light deflecting element configuration and surface light source device

[0027]Herein, the rule for arranging light deflecting elements in a plane is defined as the following before the embodiments of the invention are explained.

[0028]As shown in FIG. 2A, when light deflecting elements are distributed in a polar coordinate plane, an arrangement where light deflecting elements P1, P2, and P3 positioned substantially in a line is defined as “arranging along r direction (radial direction) of the polar coordinate plane”, while an arrangement where light deflecting elements P3, P4, and P5 positioned on the circumference of a concentric circle at different angles θ is defined as “arranging along θ direction (angular direction) of the polar coordinate plane”. On the other hand, as shown in FIG. 2B, when light deflecting elements are distributed in a Cartesian coordinate plane, an arrangement where light deflecting elements Q1, Q2 and Q3 positioned in a horizontal line is defined as “arranging along X-axis direction of the Cartesian coordinate plane”, while light d