Illumination apparatus and methods of forming the same
In one aspect, an illumination apparatus includes a waveguide, embedded in which are a light-emitting source and a photoluminescent material. Output light is emitted from at least a portion of a first surface of the waveguide. The photoluminescent material includes nano-size phosphor particles and/or quantum dots.
1. An illumination apparatus comprising:
a substantially planar waveguide;
at least one bare-die light-emitting diode (LED) embedded within the waveguide, wherein the waveguide (i) retains therein substantially all light emitted by the at least one LED, and (ii) causes the light to propagate and diffuse within the waveguide until the light is caused to exit from an exit region thereof; and
spaced away from the at least one LED, at least one photoluminescent material for converting a wavelength of a portion of the light emitted by the at least one LED.
2. The illumination apparatus of claim 1 , wherein the at least one photoluminescent material is configured to substantially eliminate back-scattering of light from the at least one photoluminescent material to the at least one LED.
3. The illumination apparatus of claim 2 , wherein the waveguide comprises:
a discrete in-coupling region for receiving source light;
a discrete out-coupling region for emitting output light; and
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.
4. The illumination apparatus of claim 1 , wherein the waveguide comprises:
a discrete in-coupling region for receiving source light;
a discrete out-coupling region for emitting output light; and
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.
5. The illumination apparatus of claim 4 , wherein (i) the waveguide comprises top and bottom opposing surfaces, (ii) the exit region is at least a portion of the top surface of the waveguide, and (iii) the at least one LED is disposed proximate the bottom surface.
6. The illumination apparatus of claim 4 , wherein (i) the waveguide comprises top and bottom opposing surfaces, (ii) the exit region is at least a portion of the top surface of the waveguide, and (iii) the at least one LED is disposed proximate a side surface spanning the top and bottom surfaces.
7. The illumination apparatus of claim 4 , wherein the at least one photoluminescent material is disposed above and in mechanical contact but not in optical contact with the exit region.
8. The illumination apparatus of claim 1 , further comprising a reflective material proximate a bottom surface of the waveguide.
9. The illumination apparatus of claim 8 , wherein the at least one photoluminescent material is disposed above and in mechanical contact but not in optical contact with the exit region.
10. The illumination apparatus of claim 9 , wherein (i) the exit region is at least a portion of a top surface of the waveguide opposite the bottom surface, and (ii) the at least one LED is disposed proximate the bottom surface.
11. The illumination apparatus of claim 9 , wherein (i) the exit region is at least a portion of a top surface of the waveguide opposite the bottom surface, and (ii) the at least one LED is disposed proximate a side surface spanning the top and bottom surfaces.
12. The illumination apparatus of claim 8 , wherein (i) the exit region is at least a portion of a top surface of the waveguide opposite the bottom surface, and (ii) the at least one LED is disposed proximate the bottom surface.
13. The illumination apparatus of claim 8 , wherein (i) the exit region is at least a portion of a top surface of the waveguide opposite the bottom surface, and (ii) the at least one LED is disposed proximate a side surface spanning the top and bottom surfaces.
14. The illumination apparatus of claim 1 , wherein (i) the waveguide comprises top and bottom opposing surfaces, (ii) the exit region is at least a portion of the top surface of the waveguide, and (iii) the at least one LED is disposed proximate the bottom surface.
15. The illumination apparatus of claim 1 , wherein (i) the waveguide comprises top and bottom opposing surfaces, (ii) the exit region is at least a portion of the top surface of the waveguide, and (iii) the at least one LED is disposed proximate a side surface spanning the top and bottom surfaces.
16. The illumination apparatus of claim 1 , wherein light emitted from the exit region has a uniformity of at least 70%.
17. The illumination apparatus of claim 1 , wherein unconverted light from the at least one LED mixes with light converted by the at least one photoluminescent material to produce substantially white light.
18. The illumination apparatus of claim 1 , wherein the waveguide comprises top and bottom opposing surfaces, and further comprising at least one reflector on a side surface spanning the top and bottom surfaces.
19. The illumination apparatus of claim 1 , further comprising at least one electrical contact extending from the at least one LED outside of the waveguide.
20. The illumination apparatus of claim 1 , wherein the at least one photoluminescent material is disposed within the waveguide proximate the at least one LED.
21. The illumination apparatus of claim 20 , wherein the waveguide comprises:
a discrete in-coupling region for receiving source light;
a discrete out-coupling region for emitting output light; and
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.
22. The illumination apparatus of claim 20 , wherein (i) the waveguide comprises top and bottom opposing surfaces, (ii) the exit region is at least a portion of the top surface of the waveguide, and (iii) the at least one LED is disposed proximate the bottom surface.
23. The illumination apparatus of claim 20 , wherein (i) the waveguide comprises top and bottom opposing surfaces, (ii) the exit region is at least a portion of the top surface of the waveguide, and (iii) the at least one LED is disposed proximate a side surface spanning the top and bottom surfaces.
24. The illumination apparatus of claim 20 , wherein light emitted from the exit region has a uniformity of at least 70%.
25. The illumination apparatus of claim 20 , wherein unconverted light from the at least one LED mixes with light converted by the at least one photoluminescent material to produce substantially white light.
26. The illumination apparatus of claim 20 , wherein the waveguide comprises top and bottom opposing surfaces, and further comprising at least one reflector on a side surface spanning the top and bottom surfaces.
27. The illumination apparatus of claim 20 , further comprising at least one electrical contact extending from the at least one LED outside of the waveguide.
28. The illumination apparatus of claim 1 , wherein at least a portion of the at least one photoluminescent material is disposed along an edge of the waveguide, and further comprising a reflector disposed at the edge of the waveguide.