Planar remote phosphor illumination apparatus

An illumination apparatus comprising:

• a substantially planar waveguide having (i) top and bottom opposed surfaces, (ii) an input region for receiving light, and (iii) spatially separated from the input region, an output region for emitting light, the output region comprising at least a portion of the top surface of the waveguide, wherein at least a portion of the waveguide confines light by total internal reflection from an interface between a surface of the waveguide and a surrounding ambient;
• a light source for emitting light into the input region;
• disposed on a surface of the waveguide in the input region, a layer of phosphor material for converting a portion of light emitted from the light source to a different wavelength;
• disposed on the layer of phosphor material in the input region, a reflector for reflecting converted and unconverted light back into the input region, the reflected converted light combining with unconverted light from the light source to form, within the input region, mixed light that is substantially uniform in at least one of intensity or color;
• and
• an out-coupling structure, disposed in the output region, for disrupting total internal reflection of substantially uniform mixed light received from the input region such that the substantially uniform mixed light is emitted from the output region.