| 摘要 |
PROBLEM TO BE SOLVED: To provide a direct type surface light source device of a multiple reflection diffusion method which has high front brightness and luminance and can minimize spots.SOLUTION: A direct type surface light source device includes: a housing bottom plate 2 on which directive point light sources are arranged; housing lateral plates 3; and light emission parts 4, a light diffusion laminate in which a first light diffusion member 6, a lens film 7 and a second light diffusion member 8 are laminated such that the first light diffusion member 6 and the opposite surface of a lens surface of the lens film 7 are brought into contact with each other, and the second light diffusion member 8 and a lens surface of the lens film 7 are brought into contact with each other being installed on the light emission surface side of the light emission part 4 such that the surface of the second light diffusion member 8 side becomes the outer side. Therein, the direct type surface light source device is characterized in that (1) a total light transmittance/parallel light transmittance ratio of the first light diffusion member 6 is 8 to 110, (2) a surface glossiness of the second light diffusion member 8 side in such a state that the second light diffusion member 8 is overlapped on the lens surface of the lens film 7 is 5 to 80% and (3) a total light transmittance/parallel light transmittance ratio of the second light diffusion member 8 is 1.0 to 30. |
