SCRATCH-SAFE REAR PROJECTION SCREEN AND METHOD FOR ITS MANUFACTURE Russian patent published in 2009 - IPC G03B21/62 

FIELD: physics, optics.

SUBSTANCE: rear projection screen contains one light-diffusing polymethyl methacrylate layer, which includes polymethyl methacrylate matrix, and also spherical diffusing particles (A) and speherical particles (B). At that particles (A) have size from 0.1 to 40 micrometer with index of refraction, which differs from refraction index of polymethyl methacrylate matrix by value from 0.02 to 0.2. Particles (B) have size from 10 to 150 micrometer and refraction index, which differs from refraction index of polymethyl methacrylate matrix by value from 0 to 0.2. Total concentration of particles (A) and particles (B) makes from 1 to 60 wt % in equivalent to mass of light-diffusing polymethyl methacrylate layer. Concentration c_PA of particles (A), thickness d_S of light-diffusing polymethyl methacrylate layer, and also size D_PA of spherical diffusing particles (A) are selected so that ratio c_PA·d_S/D_PA ³ makes from 0.001 to 0.015% wt·mm/mcm³, concentration c_PB of particles (B), thickness d_s of light-diffusing polymethyl methacrylate layer, and also size D_PB of spherical particles (B) are selected so that ratio C_PB·d_S/D_PB ³ makes from 0.000005 to 0.002% wt·mm/mcm³ and ratio of average roughness R_Z of polymethyl methacrylate layer surface squared to size of spherical particles (B) cubed, R_z ²/D_PB ³, makes from 0.0002 to 0.1300 mcm^-1.

EFFECT: cocreation of scratch-safe rear rejection screen.

29 cl