Patent ID: 6991357

Claim:
A lamp which, in a plane parallel to a light exit surface, is at least partially symmetrical with respect to a center (Z), said lamp including at least one light source, a light distribution device being also at least partially symmetrical with respect to said center in said plane and comprising light coupling-out structures and defining said light exit surface, the light of the at least one light source being fed into the light distribution device to produce a light flux which is firstly propagated through the light distribution device substantially parallel to the light exit surface and in a radial direction with respect to the center (Z) and from which light flux light components are deflected by means of the coupling-out structures for delivery through the light exit surface, the coupling-out structures comprising a plurality of coupling-out layers which are arranged at spacings in succession in the direction of propagation of the light flux and which comprise a medium whose optical refractive index is different from that of the medium filling intermediate spaces between said layers, wherein the coupling-out layers are so inclined relative to the propagation direction of the light flux at a predetermined angle that its main component passes through them without a substantial change in direction while a minor part is reflected towards the light exit surface.