Patent ID: 6963447

Claim:
A light diffusing agent which, in use, is dispersed in a transparent base material or medium, said tight diffusing agent comprising core particles and a skin layer covering the surface of the core particles, said tight diffusing agent satisfying requirements (i) and (ii): N 1 <N 2 <N 3 or N 3 <N 2 <N 1 requirement (i) wherein N 1 represents the refractive index of the transparent base material or medium, N 2 represents the refractive index of the skin layer, and N 3 represents the refractive index of the core particles; and requirement (ii): T = R 2 + ( 2 ⁢ n + 1 4 ⁢ ψ ) 2 + 2 4 ⁢ ( 2 ⁢ n + 1 ) - R wherein R represents the average radius of core particles in μm, T represents the thickness of the skin layer in μm, n is an integer of not less than 0 (zero), and ψ is 380 nm to 780 nm.