Planar remote phosphor illumination apparatus
In various embodiments, an illumination apparatus features spatially separated input and output regions, a light source, a phosphor for light conversion, and an out-coupling structure.
1. An illumination apparatus comprising:
a substantially planar waveguide having (i) top and bottom opposed surfaces, (ii) a first input region for receiving light, and (iii) spatially separated from the first input region, a first output region for emitting light, wherein (i) 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 environment, and (ii) the waveguide has either (a) a single output surface consisting of a single unitary portion of the top surface of the waveguide without any reflectors disposed thereover, light being emitted from the top surface of the waveguide only through the output surface, or (b) a first output surface consisting of a single unitary portion of the top surface of the waveguide without any reflectors disposed thereover and a second output surface consisting of a single unitary portion of the bottom surface of the waveguide without any reflectors disposed thereunder, light being emitted from the top and bottom surfaces of the waveguide only through the first and second output surfaces;
a first light source for emitting light into the first input region;
disposed on a surface of the waveguide only in the first input region, a layer of phosphor material for converting a portion of light emitted from the first light source to a different wavelength;
disposed on the layer of phosphor material in the first input region, a first reflector for reflecting converted and unconverted light back into the first input region, the reflected converted light combining with unconverted light from the first light source to form, within the first input region, mixed light that is substantially uniform in at least one of intensity or color; and
an out-coupling structure, disposed only in the first output region, for disrupting total internal reflection of substantially uniform mixed light received from the first input region such that the substantially uniform mixed light is emitted from the first output region,
wherein a surface of the waveguide inwardly protrudes in the first input region to form a protrusion.
2. The apparatus of claim 1 , wherein the mixed light increases in uniformity within the first input region along a direction toward the first output region and is substantially uniform entering the first output region.
3. The apparatus of claim 1 , wherein the out-coupling structure comprises a plurality of discrete optical elements.
4. The apparatus of claim 3 , wherein the optical elements comprise at least one of prisms, hemispheres, scattering particles, or diffusive dots.
5. The apparatus of claim 1 , wherein the first light source is at least partially embedded within the waveguide.
6. The apparatus of claim 1 , wherein the first light source comprises a light-emitting diode.
7. The apparatus of claim 6 , further comprising (i) a substrate upon which the light-emitting diode is disposed, and (ii) a second reflector disposed over the substrate.
8. The apparatus of claim 1 , wherein a surface of the waveguide in the first input region has a curvature for reflecting light toward the first output region.
9. The apparatus of claim 1 , further comprising a heat sink thermally connected to the phosphor material.
10. The apparatus of claim 1 , wherein the layer of phosphor material is in optical contact with the waveguide.
11. The apparatus of claim 1 , wherein the waveguide has one or more side surfaces spanning the top and bottom surfaces, further comprising a second reflector disposed over each of the side surfaces of the waveguide to prevent transmission of light therethrough.
12. The apparatus of claim 1 , further comprising:
a second input region (i) for receiving light, (ii) disposed within the waveguide, and (iii) spatially separated from the first input and first output regions; and
a second light source, different from the first light source, for emitting light into the second input region.
13. The apparatus of claim 12 , further comprising:
disposed on a surface of the waveguide in the second input region, a second layer of phosphor material for converting a portion of light emitted from the second light source to a different wavelength; and
disposed on the second layer of phosphor material in the second input region, a second reflector for reflecting converted light and unconverted light back into the second input region, the reflected converted light combining with unconverted light from the second light source to form, within the second input region, mixed light that is substantially uniform in at least one of intensity or color.
14. The apparatus of claim 1 , wherein the first light source is disposed at the bottom surface of the waveguide in the first input region and faces the top surface of the waveguide.
15. The apparatus of claim 1 , wherein the waveguide has the single output surface consisting of a single unitary portion of the top surface of the waveguide without any reflectors disposed thereover.
16. The apparatus of claim 15 , wherein the first reflector is disposed over a second portion of the top surface of the waveguide proximate the output surface.
17. The apparatus of claim 1 , wherein the waveguide has the first output surface consisting of a single unitary portion of the top surface of the waveguide without any reflectors disposed thereover and the second output surface consisting of a single unitary portion of the bottom surface of the waveguide without any reflectors disposed thereunder.
18. The apparatus of claim 14 , wherein the bottom surface of the waveguide inwardly protrudes in the first input region to form the protrusion.
19. The apparatus of claim 14 , wherein the top surface of the waveguide inwardly protrudes in the first input region to form the protrusion.
20. The apparatus of claim 1 , wherein the bottom surface of the waveguide inwardly protrudes in the first input region to form the protrusion.
21. The apparatus of claim 1 , wherein the top surface of the waveguide inwardly protrudes in the first input region to form the protrusion.
22. The apparatus of claim 1 , wherein the first light source emits light into the input region from the same surface of the waveguide that inwardly protrudes to form the protrusion.
23. The apparatus of claim 1 , wherein the first light source emits light into the input region from a surface of the waveguide different from the surface of the waveguide that inwardly protrudes to form the protrusion.
24. The apparatus of claim 1 , wherein the first reflector extends over at least a portion of the protrusion.
25. The apparatus of claim 1 , wherein the layer of phosphor material extends over at least a portion of the protrusion.
26. The apparatus of claim 1 , further comprising a heat sink thermally connected to both the layer of phosphor material and the first light source.
27. The apparatus of claim 1 , wherein, in the first input region, the waveguide has a side surface spanning the top and bottom surfaces of the waveguide.
28. The apparatus of claim 27 , wherein the side surface of the waveguide is substantially perpendicular to at least one of the top or bottom surfaces of the waveguide.
29. The apparatus of claim 7 , wherein the protrusion is disposed over the substrate.