| 摘要 |
PROBLEM TO BE SOLVED: To provide a plane light source device, as well as a light guide member, which is so made to avoid occurrence of dark spots in response to the outside of a luminous region of a light source in a simple structure. SOLUTION: With the plane light source device 10 involving a light guide member 11 consisting of a flat translucent material, a reflecting sheet 12 arranged in opposition to the undersurface of the light guide member, a light diffusion member 13 and a prism sheet 14 arranged in opposition to the top surface of the light guide member, a cylindrical slim light source 15 arranged in opposition to one side face 11a of the light guide member, and an almost semi-cylindrical reflective member 16 surrounding the light source so as to leave the light guide member side open, the above one side face 11a of the light guide plate is to be provided with a notch part each near the end part slanted toward the other end so as to completely oppose a luminous region 15b of the light source 15. |
