Patent ID: 8890395

Claim:
A beamshaping optical stack, comprising a first light transmitting layer of a first material having a first refractive index, a second light transmitting layer of a second material having a second refractive index, and one or more additional light transmitting layers of a third or more material interposed between the first light transmitting layer and the second light transmitting layer, wherein the one or more additional light transmitting layers allow the transmission of light from the first light transmitting layer towards the second light transmitting layer, and the refractive indices of the third or more material of the one or more additional light transmitting layers are larger than the first refractive index and smaller than the second refractive index, the second light transmitting layer comprising i) a first side being optically coupled to the first light transmitting layer for receiving light from the first light transmitting layer, ii) a second side being substantially opposite the first side for emitting the received light into another optical medium, and iii) a geometrical structure at the second side for obtaining a decreasing light emission with increasing light emission angles with respect to a normal to the first side, wherein the first refractive index is lower than the second refractive index.