| 摘要 |
<P>PROBLEM TO BE SOLVED: To raise use efficiency of light at the time of use of an LED as a light source, with a flat light-emitting face. <P>SOLUTION: A light guide plate 4 of a plane light source device 1 includes a first prism 44a arranged on a light-incident surface 44 so as to be in contact with a light-emitting surface 17a and dispersing emitted light from the light source 17, a second prism arranged by forming a recessed section 46 from at least either a light-emitting surface 42 and a back surface 41 to a route of incident light and reflecting a part of the incident light dispersed with the first prism 44a, and a pair of third prisms arranged by forming a pair of inclined surfaces 45 inclined in a direction separated from each other while keeping away from the light source 17 on both sides of the second prism in a direction along a line of intersection between the light-emitting surface 42 and the light-incident surface 44, and reflecting a part of the incident light reflected with the second prism in a direction of the reflecting surface. <P>COPYRIGHT: (C)2011,JPO&INPIT |
