Optical waveguide and lamp including same
An optical waveguide includes a body of optically transmissive material having a width substantially greater than an overall thickness thereof and including a first side, a second side opposite the first side, a central bore extending between the first and second sides and adapted to receive a light emitting diode, and extraction features on the second side. A light diverter extends into the central bore for diverting light into and generally along the width of the body of material. The extraction features direct light out of the first side and wherein at least one extraction feature has an extraction surface dimension transverse to the thickness that is between about 5% and about 75% the overall thickness of the body of material.
1. A lamp, comprising:
a base having an electrical connector;
a central body disposed on the base;
a driver circuit disposed in the central body and coupled to the electrical connector; and
a light assembly joined to the central body, wherein the light assembly includes a waveguide comprising a first surface and a second surface that terminate in an outer surface to define a waveguide body, the waveguide body surrounding an interior coupling cavity disposed such that the waveguide body extends radially from the interior coupling cavity, at least one LED disposed in the interior coupling cavity and connected to the driver circuit such that the at least one LED emits light into the waveguide body when activated by the driver circuit, the light propagating radially outwardly through the waveguide body between the first surface and the second surface to the outer surface, and a plurality of extraction features disposed in and spaced across the second surface of the waveguide body, the plurality of extraction features reflecting the light to the first surface, the light being emitted from the waveguide through the first surface; wherein light emitted at radially outward portions of the first surface are directed axially inwardly at an inward angle, the inward angle being substantially proportional to a radial distance of emission of the light from the center of the waveguide.
2. The lamp of claim 1 , wherein the plurality of extraction features comprise a plurality of concentric grooves in the second surface.
3. The lamp of claim 1 , wherein the plurality of extraction features comprise a plurality of spaced grooves in the second surface.
4. The lamp of claim 2 , wherein the plurality of extraction features are continuous and surround the interior coupling cavity.
5. The lamp of claim 2 , wherein the plurality of extraction features direct light over substantially the entire first surface.
6. The lamp of claim 2 , wherein the plurality of extraction features are discontinuous.
7. The lamp of claim 1 , wherein the at least one LED comprises a plurality of LEDs disposed on a carrier.
8. The lamp of claim 7 , wherein the plurality of LEDs direct light transversely through the waveguide body.
9. The lamp of claim 1 , wherein the electrical connector comprises an Edison style plug.
10. The lamp of claim 1 , wherein the interior coupling cavity comprises a central bore.
11. The lamp of claim 10 , further including a conical plug member disposed in the central bore.
12. The lamp of claim 11 , wherein the conical plug member includes a conical reflective surface.
13. The lamp of claim 12 , wherein the at least one LED directs light onto the conical reflective surface where the light is diverted transversely into the waveguide body.
14. The lamp of claim 1 , wherein the light assembly further includes a heat exchanger.
15. The lamp of claim 14 , wherein the heat exchanger eliminates thermal crosstalk between the at least one LED and the driver circuit.
16. The lamp of claim 1 , further including a plurality of arms carried by the central body and joined to the light assembly.
17. The lamp of claim 16 , wherein four arms of the plurality of arms are disposed between the central body and the light assembly.
18. The lamp of claim 16 , wherein two arms of the plurality of arms are disposed between the central body and the light assembly.
19. The lamp of claim 1 , wherein each extraction feature has an aspect ratio of between about 0.25 and about 29.
20. The lamp of claim 1 , wherein each extraction feature has an aspect ratio of between about 0.5 and about 10.
21. The lamp of claim 1 , wherein each extraction feature has an aspect ratio of between about 0.75 and about 7.5.
22. The lamp of claim 1 , wherein the waveguide body creates a beam angle of emitted light between less than 5 degrees to greater than 60 degrees.
23. The lamp of claim 1 , wherein the waveguide body creates a beam angle of emitted light between about 5 degrees and about 50 degrees.
24. The lamp of claim 1 , wherein the waveguide body creates a beam angle of emitted light between about 6 degrees and about 40 degrees.
25. The lamp of claim 1 , wherein the waveguide body is substantially circular.
26. The lamp of claim 1 , wherein the waveguide body is a non-circular shape.
27. The lamp of claim 1 , in combination with a luminaire including a trim ring having an aperture having a first cross sectional size and wherein the waveguide body has a second cross sectional size and wherein the first cross sectional size of the aperture is less than or equal to the second cross sectional size of the waveguide body, the waveguide body comprising a plurality of extraction features in the second surface arranged such that light emitted at radially outward portions of the first surface are directed axially inwardly at an inward less than or equal to the second cross sectional size of the waveguide body.
28. The combination of claim 27 , wherein the second cross sectional size of the aperture relative to the first cross sectional size of the waveguide body is between about 1:2 and about 1:4.
29. The lamp of claim 1 , wherein the interior coupling cavity is defined by a wall, the interior cavity being tapered.
30. The lamp of claim 29 , wherein the wall of the interior coupling cavity comprises a plurality of facets.
31. The lamp of claim 30 , wherein a V-shaped groove extends into the waveguide body from the first surface.
32. The lamp of claim 31 , further including lenslets disposed on the first surface.
33. The lamp of claim 32 , further including additional extraction features disposed on the first surface.
34. The lamp of claim 33 , wherein the additional extraction features comprise ribs.
35. The lamp of claim 1 , wherein the plurality of extraction features comprise a plurality of prisms.
36. The lamp of claim 35 , wherein the plurality of prisms are identical to one another and face the interior coupling cavity.
37. The lamp of claim 35 , wherein the plurality of prisms are different from one another.
38. The lamp of claim 1 , wherein the plurality of extraction features are substantially identical to one another.
39. The lamp of claim 1 , wherein the plurality of extraction features are different from one another.