| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a surface light source device having a high luminance used abundantly for a liquid crystal device. <P>SOLUTION: This is a surface light source device which has a light guide body having a light incident surface and a light outgoing surface, a light source provided opposed to the light incident surface, and a light focusing member arranged on the light outgoing surface of the light guide body. A light extraction mechanism of a projection shape in which the relation of the width W and the height H is H/W=0.1-1.5 in the advancing direction of the light from the light source is installed at the light outgoing surface of the light guide body with a pitch of 2H-8H, and the focusing member is constructed of a prism array in which a prism with its apex angle facing the light outgoing surface is arranged with a pitch of 1-500 μm, and the longitudinal direction of the prism array is arranged at right angles to the principally advancing direction of the light from the light source, and the apex angle is 20-48° against the normal line in the angle opposite side to the light source. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
