Patent ID: 8727597

Claim:
An illumination apparatus comprising: a waveguide having a first surface; embedded within the waveguide, a light-emitting source for emitting source light; disposed on the first surface of the waveguide, a layer of phosphor-encapsulating material; and disposed within the layer of phosphor-encapsulating material, a photoluminescent material for converting some of the source light to a different wavelength, the converted source light mixing with unconverted source light to form output light spectrally different from both the converted source light and the unconverted source light, wherein (i) source light is emitted from at least a portion of the first surface of the waveguide, (ii) output light is emitted from at least a portion of the layer of phosphor-encapsulating material, (iii) the waveguide comprises (a) a discrete in-coupling region for receiving source light, (b) a discrete out-coupling region for emitting output light, and (c) a discrete propagation region, spatially distinct from the in-coupling and out-coupling regions, for propagating source light from the in-coupling region to the out-coupling region, and (iv) the photoluminescent material is present only over the out-coupling region.