Scratch-resistant rear projection screen and method for producing the same

US7339732B2 · kind B2 · utility

Assignee

• ROEHM GMBH & CO. KG · DE

Inventors

• Markus Parusel · Messel, DE
• Jann Schmidt · Darmstadt, DE
• Herbert Groothues · Frankfurt, DE
• Christoph Krohmer · Riedstadt, DE
• Guenther Dickhaut-Bayer · Riedstadt, DE

Key dates

• Filing date: Mar 12, 2004
• Grant date: Mar 4, 2008
• Expiry date: Sep 17, 2024

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B5/0294
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

The present invention relates to a rear-projection screen encompassing at least one light-scattering polymethyl methacrylate layer, which comprises a polymethyl methacrylate matrix and spherical scattering particles (A) and spherical particles (B) with a different median particle size V50, where the spherical scattering particles (A) have a median size V50 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, where 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 where 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, where the concentration of the spherical scattering particles (A) cPA, the thickness of the light-scattering polymethyl methacrylate layer dS and the size of the spherical scattering p…