| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable to reduce decrease of light incident efficiency and to make brightness higher even when a thickness of a light guide plate becomes thinner than a light-emission thickness of a light source in a light guide type surface light source element. <P>SOLUTION: For the surface light source element equipped with a light source, a light guide plate, and an emission light control plate, a convex part of the emission light control plate is optically adhered closely to the light guide plate, an emitting face of the light guide plate and the emitted light control plate are optically adhered closely within a range of at least 0.5 mm from a light source arranging side end face in a surface-shape, and when a thickness of the light guide plate is T1, a thickness of the emitted light control plate is T2, and a light-emission length in a thickness direction of the light guide plate of the light source is H, there is a relationship shown in a formula (1), T<SB>1</SB><H<T<SB>1</SB>+T<SB>2</SB>. <P>COPYRIGHT: (C)2009,JPO&INPIT |
