US Patent 10042109 Lighting unit comprising a waveguide

The invention provides a lighting unit comprising a waveguide for providing first light (111) having a first spectral distribution and second light (121) having a second spectral distribution emanating from a waveguide (100) in different directions, wherein the first spectral distribution and second spectral distribution differ. For instance, the first light (111) and the second light (121) have different color temperatures.