| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface light source device and a liquid crystal display using it, capable of maintaining sufficient wide angle-of-visibility property while using scattered light with high brightness and high directivity generated from a coarse face or light scattering particles, simple to construct for high facing brightness and easy to manufacture. SOLUTION: A surface light source device comprises a light takeoff means 17 provided on a light conductor 11 with one face as a light emission face 16, light sources 12 at the opposed ends 14, 15 and a light adjusting sheet 21 on the light emission face, the light takeoff means 17 being formed with a coarse face or light scattering particles and the light adjusting sheet 21 having a deformation optical system defined so that the angle-of-visibility distribution property of an illumination, obtained by lighting one of the light sources 12 arranged at both ends 14, 15, in the direction perpendicular to the light sources is asymmetrical with a steep area 31a and a gentle area 31b at the border of a peak when it is expressed in a property diagram with a brightness at a vertical axis and an emission angle at a lateral axis and the property diagrams shown by illuminations from both light sources when lit on at the same time are combined to cross each other in the gentle area 31b. |
