| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light guide body to enable a surface light source device of high luminance and high quality. <P>SOLUTION: A plate-like light guide body 3 guides a primary light source light, and has a light incident end face 31, a light emitting face 33 and a rear face 34. On the rear face 34, a plurality of vertical prism rows 34a extending in a direction crossing the light incident end face 31 are arranged parallel to each other. A cross-sectional shape of the vertical prism rows 34a is different in a first region RC1 neighboring the light incident end face and in a second region RC2 positioned far from the light incident end face, and consisting of a first arc of a radius of 5 to 25 μm in the first region, and a second arc of the radius of 5 to 25 μm positioned between a pair of inclined sides forming angles of 120 to 140° therebetween in the second region. The dimension of the first region RC1 regarding the extension direction of the vertical prism rows 34a is within a range of 1 to 2 times the thickness of the light guide body in the light incident end face, and the height of the vertical prism rows in the first region RC1 is within a range of 0.3 to 3 μm, and lower than the height of the vertical prisms of the second region RC2. <P>COPYRIGHT: (C)2010,JPO&INPIT |
