Light diffusion sheet and liquid crystal display device

Abstract

A light diffusing layer 10 included in a light diffusing sheet and a liquid crystal display device of the present invention includes a plurality of low refractive index regions (second regions) 14 formed of a substance which has a low refractive index (second substance). The shape of each of the low refractive index regions in a cross section perpendicular to the major surface is approximated to an isosceles triangle where the base is on the viewer side and the vertex is on the liquid crystal display panel side. The plurality of low refractive index regions are arranged in a high refractive index region (first region) formed of a high refractive index substance (first substance) at a predetermined pitch P in at least one direction in a plane parallel to the major surface. The shape and size of the low refractive index regions satisfy a predetermined relationship, and therefore, light which is perpendicularly incident on the major surface undergoes total reflection only once inside the light diffusing layer before outgoing from the light diffusing layer toward the viewer side, and part of the light which is incident on the major surface at an oblique angle undergoes total reflection n or more times (n is an integer not less than 2) inside the light diffusing layer before outgoing from the light diffusing layer toward the viewer side. As a result, the viewing angle characteristic in the at least one direction is improved.

Dependencies are inferred from the claim text.