US Patent 7740375 High brightness illumination device with incoherent solid state light source

An illumination light source includes an incoherent solid state light source adapted to emit light over at least one light emission surface and having a total light emission surface area S0; a light circulation device including at least one light receiving surface adapted to receive the light from the incoherent solid state light source, and a light extraction area having a first surface area S1; and a light extraction device for extracting the light from the light circulation device at the light extraction area, wherein S1<S0. Accordingly, the apparent brightness of the light is increased by distributing it over a smaller area.