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, (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, (iv) spatially separated from and disposed between the input and output regions, a conversion region for receiving light from the input region, mixing the received light with light generated in the conversion region, and propagating the mixed light to the output region, 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;
• an aperture, separating the input region from the conversion region, for permitting propagation of light from the input region while substantially preventing reflection of light within the conversion region back into the input region;
• disposed in the conversion region, a phosphor material for converting a portion of light received from the input region to a different wavelength, the converted light mixing with unconverted light within the conversion region to form, within the conversion 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 conversion region such that the substantially uniform mixed light is emitted from the output region.