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US 7,064,894 B2Granted
Rear projection screen and method for the production thereof
AssigneeRoehm GmbH
InventorsMarkus Parusel, Jann Schmidt, Herbert Groothues, Wolfgang Scharnke, Hans Lorenz, Helmut Haering, Guenther Dickhaut-Bayer
Life of this patent
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Abstract
A rear-projection screen that has at least one light-scattering polymethyl methacrylate layer in which is embedded spherical plastic particles; the previously described rear-project screen that has an additional plastic sheet that does not have embedded scattering beads; and a method of making a rear-projection screen.
Claims18
A rear-projection screen, comprising:
- at least one light-scattering polymethyl methacrylate layer of thickness in the range from 0.05 to 4 mm comprising
- spherical plastic particles whose size is in the range from 5 to 35 μm at a concentration in the range from 2 to 60% by weight, based on the total weight of the light-scattering polymethyl methacrylate layer;
- wherein the refractive index of the spherical plastic particles differs from that of the polymethyl methacrylate layer by a value in the range from 0.02 to 0.2;
- wherein the concentration of the spherical plastic particles cP, the thickness of the light-scattering polymethyl methacrylate layer dS, and the size of the spherical plastic particles DP are selected in such a way that the ratio cP*dS/DP3 is in the range from 0.0015 to 0.015% by weight*mm/μm3;
- and
- the ratio of average surface roughness of the polymethyl methacrylate layer Ra to the size of the spherical plastic particles DP is in the range from 0.05 to 0.4.
3 more elements
Dependencies are inferred from the claim text.