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:
Dec. 08, 2009
Filed:
May. 12, 2004
Markus Parusel, Messel, DE;
Jann Schmidt, Rockaway, NJ (US);
Herbert Groothues, Weiterstadt, DE;
Evonik Roehm GmbH, Darmstadt, DE;
Abstract
The present invention relates to diffuser sheets for LCD applications encompassing at least one light-scattering polymethyl methacrylate layer which comprises a polymethyl methacrylate matrix and also from 0.5 to 59.5% by weight, based on the weight of the light-scattering polymethyl methacrylate layer, of spherical scattering particles (A) whose median size Vis in the range from 0.1 to 40 μm, and whose refractive index differs from that of the polymethyl methacrylate matrix by a value in the range from 0.02 to 0.2, and from 0.5 to 59.5% by weight, based on the weight of the light-scattering polymethyl methacrylate layer, of spherical particles (B) whose median size Vis in the range from 10 to 150 μm and whose refractive index differs from that of the polymethyl methacrylate matrix by a value in the range from 0 to 0.2, 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, and the spherical scattering particles (A) and spherical particles (B) have a different median particle size V, where the transmittance of the diffuser sheets is in the range from 20 to 70% and their scattering power is greater than 0.3, where 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.