DIFFUSER DISK FOR LCD APPLICATIONS, METHOD FOR THE PRODUCTION AND USE THEREOF

摘要

A scattering screen for LCD applications comprises at least one light scattering polymethylmethacrylate layer comprising a polymethylmethacrylate matrix and spherical particles (A) and spherical particles (B) having different average particle sizes with at least one particle type having a refractive index that is different to that of polymethylmethacrylate matrix. A scattering screen for LCD applications comprises at least one light scattering polymethylmethacrylate layer comprising a polymethylmethacrylate matrix and 0.5-59.5 wt.% of spherical scattering particles (A) having an average particle size of 0.1-40 mu m and a refractive index that is different to that of polymethylmethacrylate matrix by 0.02-2 and 0.5-59.5 wt.% of spherical scattering particles (B) having an average particle size of 10-150 mu m and a refractive index that is different to that of polymethylmethacrylate matrix by 0-0.2 wherby the total concentration of (A) and (B) is 1-60 wt.% (with respect to the light scattering polymethylmethacrylate layer) and the particles (A) and (B) are of different average particle diameter and the screen (I) has a transmission value of 20-70% and scattering level of greater than 0.3 whereby ratio of the square of the average surface roughness of the polymethylmethacrylate layer R z to the cube of the particle size of (B) R 2> z/DPB3 is 0.0002-0.1300 mu m -> 1>. An independent claim is included for a process for the production of the screen (I) by extrusion of a composition comprising polymethylmethacrylate, particles (A) and particles (B).