SURFACE LIGHT SOURCE DEVICE

摘要

A surface light source device comprises a light emitting section (11) made of a single spot light source, a light guide plate (12), a reflective surface (13) provided on the back side of the light guide plate, and a prism pattern (15). On the light emitting surface side of the light guide plate (12), there is provided a directional light scattering film (14) consisting of at least two phases having different refractive indexes and scattering light when transmitting it. One phase of a larger refractive index includes a plenty of areas having a columnar structure extending in the thickness direction of a film and arranged to be perpendicular to a normal to the film, and exhibiting a maximum scattering angle of 10-40°.