| abstract |
A light-collecting device in the form of, for example, a rectangularly-shaped body having a so-called "fluorescent plate" with at least one light-exit window is comprised of a solid carrier material having an index of refraction greater than one, such as a polar, water-containing amorphous material based on a polysilicate or a polyphosphate and containing organic or inorganic fluorescent particles therein, which have finite dipole moments with different values in the basic and the excited state, with the fluorescent particles being substantially uniformly distributed throughout the carrier material. In embodiments where the fluorescent particles are organic, an amphiphilic additive, such as a soap, is colloidally dissolved in the carrier material in such a manner that the fluorescent particles are each surrounded by a colloid particle. The disclosed device is useful as a solar collector, an optical indicia transmitter or an image brightener for passive displays. |