Abstract: The invention relates to an illuminative device essentionaly comprising a light source and a diffusing cover which is assigned to the light source and is made of colored plastic. The light source consites of one or several light-emitting diodes (LEDs) emitting a colored an substantially monocromatic light. The diffusing cover assigned thereto has a transmition (DIN 5036) of at least 35% and a reflection (DIN 5036) of at least 15% with the wavelength of the light-emitting diode operating at relative maximum energy.

Abstract: The present invention relates to a light-guide body, which has at least one light-entry surface and at least one light-exit surface, the ratio of the light-exit surface area to the light-entry surface area being at least 4, comprising at least one light-guiding layer with a thickness of at least 2 mm, characterized in that the light-guiding layer comprises at least 60% by weight, expressed in terms of the weight of the light-guiding layer, of polymethyl methacrylate and from 0.001 to 0.08% by weight, expressed in terms of the weight of the light-guiding layer, of spherical barium sulphate particles with an average diameter in the range of from 0.3 to 20 ?m.

Abstract: Abstract of the Disclosure The present invention relates to rear-projection screens encompassing at least one light-scattering polymethyl methacrylate layer of thickness in the range from 0.05 to 4 mm comprising spherical 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, the refractive index of the spherical plastics particles differing from that of the polymethyl methacrylate matrix by a value in the range from 0.02 to 0.2, wherein the concentration of the spherical plastics particles cP, the thickness of the light-scattering polymethyl methacrylate layer dS, and the size of the spherical plastics particles DP is 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 plastics particles Dp is in the range from 0.

Abstract: The present invention relates to a [lacuna] having at least one light-entry surface and at least one light-exit surface, the ratio of the light-exit surface area to the light-entry surface area being at least 4, comprising at least one light-guiding layer, characterized in that the light-guiding layer comprises at least 60% by weight, expressed in terms of the weight of the light-guiding layer, of polymethyl methacrylate and from 0.0001 to 0.2% by weight, expressed in terms of the weight of the light-guiding layer, of spherical particles with an average diameter in the range of from 0.3 to 40 ?m, and the light-exit surface of the light-guiding layer is provided with structurings.

Abstract: An illuminative device including a light source and a diffusing cover assigned to the light source and of colored plastic. The light source includes one or plural light-emitting diodes (LEDs) emitting a colored and substantially monochromatic light. The diffusing cover has a transmission of at least 35% (measured according to DIN 5036) and a reflection of at least 15% (measured according to DIN 5036) with the wavelength of the light-emitting diode operating at relative maximum energy.

Abstract: The present invention relates to a light-guide body, which has at least one light-entry surface and at least one light-exit surface, the ratio of the light-exit surface area to the light-entry surface area being at least 4, comprising at least one light-guiding layer with a thickness of at least 2 mm, characterized in that the light-guiding layer comprises at least 60% by weight, expressed in terms of the weight of the light-guiding layer, of polymethyl methacrylate and from 0.001 to 0.08% by weight, expressed in terms of the weight of the light-guiding layer, of spherical barium sulphate particles with an average diameter in the range of from 0.3 to 20 &mgr;m.

Abstract: The present invention relates to rear-projection screens encompassing at least one light-scattering polymethyl methacrylate layer of thickness in the range from 0.05 to 4 mm comprising spherical particles whose size is in the range from 5 to 35 &mgr;m, at a concentration in the range from 2 to 60% by weight, based on the total weight of the light-scattering polymethyl methacrylate layer, the refractive index of the spherical plastics particles differing from that of the polymethyl methacrylate matrix by a value in the range from 0.02 to 0.2, wherein the concentration of the spherical plastics particles cp, the thickness of the light-scattering polymethyl methacrylate layer ds, and the size of the spherical plastics particles Dp is selected in such a way that the ratio cp*ds/Dp3 is in the range from 0.0015 to 0.015% by weight*mm/&mgr;m3 and the ratio of average surface roughness of the polymethyl methacrylate layer Ra to the size of the spherical plastics particles Dp is in the range from 0.05 to 0.4.