| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a surface light source device which has a lightguide disposed directly below and is equipped with preferable characteristics as a backlight of a large-sized liquid crystal display device such as high efficiency, a reduced number of linear light sources and easy thickness reduction. <P>SOLUTION: The surface light source device consists of: a lightguide 20 with a surface made to be an emission surface 20b; at least two groove parts 22 provided on the surface opposite to the emission surface 20b; two or more linear light sources 21 mounted in the groove parts 22; and a light reflection plate 23 mounted on the surface side opposite to the emission surface 20b. A light extraction mechanism 24 is arranged on one or both of the emission surface 20b and the surface opposite to the emission surface 20b. In the groove parts 22, an inequality 0.3<D/H<0.7 holds between the depth D of the groove part 22 and the thickness H of the lightguide body 20 at the groove part 22. <P>COPYRIGHT: (C)2004,JPO |
