Patent ID: 7339732

Claim:
Rear-projection screen that comprises at least one light-scattering polymethyl methacrylate layer, the rear-projection screen comprising: a polymethyl methacrylate matrix; spherical scattering particles (A); and spherical particles (B) with a median particle size V 50 different than the median particle size of the spherical scattering particles (A) wherein the spherical scattering particles (A) have a median size V 50 in the range from 0.1 to 40 μm, the difference between the refractive index of the spherical scattering particles (A) and that of the polymethyl methacrylate matrix being in the range from 0.02 to 0.2, wherein the spherical particles (B) have a median size V50 in the range from 10 to 150 μm, the difference between the refractive index of the spherical particles (B) and that of the polymethyl methacrylate matrix being in the range from 0 to 0.2, and wherein the total concentration of the spherical scattering particles (A) and particles (B) is in the range from 1 to 60% by weight, based on the weight of the light-scattering polymethyl methacrylate layer, wherein the concentration of the spherical scattering particles (A) c PA , the thickness of the light-scattering polymethyl methacrylate layer d S and the size of the spherical scattering particles (A) D PA is selected in such a way that the ratio c pA *d S /D PA 3 is in the range from 0.001 to 0.015% by weight*mm/μm 3 , the concentration of the spherical particles (B) c PB , wherein the thickness of the light-scattering polymethyl methacrylate layer d S and the size of the spherical particles (B) D PB is selected in such a way that the ratio c PB *d S /D PB 3 is in the range from 0.000005 to 0.002% by weight*mm/μm 3 and the ratio of the square of average surface roughness of the polymethyl methacrylate layer R Z to the third power of the size of the spherical particles (B) R Z 2 /D PB 3 is in the range from 0.0002 to 0.1300 μm −1 .