| 摘要 |
PROBLEM TO BE SOLVED: To emit illuminating light with simple configuration and with uniform light quantity distribution even when the primary light source is constructed with a point light source with respect to a light transmission plate, a surface light source device and a display device, for example applied to various kinds of liquid crystal display device utilizing a frontlight system or a backlight system and so on. SOLUTION: In the surface light source, the incident illuminating light from an incident plane 14A is propagated inside the light transmission plate 14 so as not to be emitted from a light emitting plane 14B as far as possible. At the same time, the illuminating light is reflected by at least a part of the side face 14F of the light transmission plate including the end face opposite to the incident plane 14A. Consequently the propagating direction of the illuminating light is converted and the propagation to the reflecting direction takes place. Meanwhile the illuminating light is emitted from the light emitting plane 14B. |
