Patent ID: 7180664
Filing Date: 2007-02-20
Classification: G03B

Abstract:
1. A light diffusion sheet or film, the light diffusion sheet or film comprising: a plurality of unit lenses formed of a material having a refractive index N1, each unit lens having a trapezoidal cross-section, wherein a first base of the trapezoidal cross-section is a light incident side of the respective unit lens and a second base is a light emitting side of the respective unit lens; at least one between lens portion, having a triangular cross-section, positioned between two of the unit lenses, wherein the at least one between lens portion is formed of a material having a refractive index N2 that is less than N1, wherein the material includes light absorption particles that account for between 10–60% of the mass of the at least one between lens portion, wherein if θ represents an angle defined by a side of the trapezoidal cross-section and a line normal to a base of the trapezoidal cross-section, then sin(90−θ)>N2/N1 and N1<1/sin(2θ); and a base sheet attached to the light incident side of the unit lenses, wherein a portion of the light incident side of the base sheet is embossed.