The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 04, 2008
Filed:
Mar. 12, 2004
Markus Parusel, Messel, DE;
Jann Schmidt, Rockaway, NJ (US);
Herbert Groothues, Weiterstadt, DE;
Christoph Krohmer, Stockstadt, DE;
Guenther Dickhaut-bayer, Riedstadt, DE;
Markus Parusel, Messel, DE;
Jann Schmidt, Rockaway, NJ (US);
Herbert Groothues, Weiterstadt, DE;
Christoph Krohmer, Stockstadt, DE;
Guenther Dickhaut-Bayer, Riedstadt, DE;
Roehm GmbH & Co. KG, Darmstadt, DE;
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 V, where the spherical scattering particles (A) have a median size Vin 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 Vin 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) c, the thickness of the light-scattering polymethyl methacrylate layer dand the size of the spherical scattering particles (A) Dis selected in such a way that the ratio c*d/Dis in the range from 0.001 to 0.015% by weight*mm/μm, the concentration of the spherical particles (B) c, the thickness of the light-scattering polymethyl methacrylate layer dand the size of the spherical particles (B) Dis selected in such a way that the ratio c*d/Dis in the range from 0.000005 to 0.002% by weight*mm/μmand the ratio of the square of average surface roughness of the polymethyl methacrylate layer Rto the third power of the size of the spherical particles (B) R/Dis in the range from 0.0002 to 0.1300 μm.