| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a surface light source device in which brightness unevenness is hard to be visibly recognizable in a region in the vicinity of the light incident end face of a light guide body, accompanying thinning of the light guide body, and which is less in specific light emission in a diagonal direction in the vicinity of the light incident end face. <P>SOLUTION: In the light guide body for the surface light source device to guide light emitted from a primary light source having the light incident end face to which light emitted from the primary light source is made incident, and a nearly rectangular light emitting face which is nearly perpendicular to the light incident end face and from which the guided light is emitted, and in the light incident end face, the average inclined angle Rθa1 in the longitudinal direction is 0.6°or more and 3°or less, a ratio (Rθa1/Rθa2) of the average inclined Rθa1 in the longitudinal direction to the average inclined angle Rθa2 in the thickness direction is 0.2 or more and 0.7 or less. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
