Patent ID: 7178949

Claim:
Lighting device, comprising: a light source; and an associated hollow reflector of transparent material having an inner surface and an outer surface, close to and far from the source respectively; the inner surface of the reflector having in cross-section, in at least one transverse plane passing through the source, a discontinuous profile forming a plurality of adjacent steps, each of which has a first face through which rays originating from the source may pass and a second face essentially parallel to the rays originating from the source; the outer surface of the reflector having a profile in the transverse plane comprising a plurality of arcs of conic curves having eccentricities, foci and axes which do not necessarily coincide with each other; the reflector being constructed and arranged in such a way that in the transverse plane most of the rays emitted by the source are refracted through the first faces of the steps on the inner surface and strike the outer surface of the reflector undergoing total internal reflection and, having passed back through the reflector, re-emerge outside the same through the second faces of the steps on the inner surface of the reflector undergoing a second refraction.