Abstract
A lamp comprises a thin layer of phosphor which is irradiated, for example by ultraviolet radiation, by a source which typically comprises a laser diode and a condenser. This causes the phosphor to emit visible light with a Lambertian-type emission pattern. An optical system such as a reflector concentrates the light form the phosphor. The phosphor is thermally connected to a heatsink, of example by a plate of sapphire glass, so as to dissipate the heat produced by the phosphor. The phosphor may be mounted on a plane reflector disposed on or comprising a heatsink and facing a curved reflector and the radiation source. Alternatively, the optical system may have an optical axis and the phosphor may be substantially flat and inclined with the respect to the optical axis.