COLOR MIXING OPTICS FOR LED ILLUMINATION DEVICE
Illumination devices with improved color mixing optics are disclosed herein for mixing the colors produced by a multi-colored LED emitter module to produce uniform color throughout the entire beam angle of the output light beam, along with smoother edges and improved center beam intensity. Embodiments disclosed herein include a unique arrangement of multi-color LEDs within an emitter module, a unique exit lens with different patterns of lenslets on opposing sides of the lens, and other associated optical features that thoroughly mix the different color components, and as such, provide uniform color across the output beam exiting the illumination device. Additional embodiments disclosed herein include a unique arrangement of photodetectors within the primary optics structure of the LED emitter module that ensure the optical feedback system properly measures the light produced by all similarly colored emission LEDs.
1 . A lamp, comprising:
a parabolic reflector;
an exit lens disposed transversely across diameter of the parabolic reflector, wherein the exit lens includes a first lenslet pattern on an interior surface of the exit lens and a second lenslet pattern formed on an exterior surface of the exit lens;
wherein the first lenslet pattern differs from the second lenslet pattern;
a plurality of light-emitting diodes (LEDs) arranged in an array disposed on a substrate and positioned at the focal point of the parabolic reflector; and
one or more photodetectors disposed on the substrate.
2 . The lamp of claim 1 wherein the parabolic reflector comprises a plurality of lunes.
3 . The lamp of claim 1 further comprising a primary optic structure that encapsulates the LED array.
4 . The lamp of claim 3 wherein the primary optic structure encapsulates the one or more photodetectors.
5 . The lamp of claim 4 wherein the primary optic structure comprises a hemispherical optic structure.
6 . The lamp of claim 1 wherein an aperture ratio of the lenslets formed on the interior surface of the exit lens to the lenslets formed on the exterior surface of the exit lens is at least 3:1.
7 . The lamp of claim 6 wherein the lenslets formed on the interior surface of the exit lens and the lenslets formed on the exterior surface of the exit lens comprise polygonal lenslets.
8 . The lamp of claim 6 wherein the lenslets formed on the interior surface of the exit lens and the lenslets formed on the exterior surface of the exit lens comprise circular lenslets.
9 . The lamp of claim 1 wherein the plurality of LEDs comprises at least three differently colored LEDs.
10 . The lamp of claim 9 wherein the at least three differently colored LEDs comprise one or more red LEDs, one or more green LEDs, and one or more blue LEDs.
11 . The lamp of claim 9 wherein the plurality of LEDs comprises at least three differently colored LED strings, each of the LED strings including a respective plurality of LEDs.
12 . The lamp of claim 10 wherein the plurality of LEDs included in the differently colored LED strings are arranged such that same color LEDs are not positioned adjacent to each other.
13 . The lamp of claim 1 further comprising a heat sink disposed proximate at least a portion of an exterior surface of the parabolic reflector.
14 . The lamp of claim 1 wherein the plurality of LEDs are arranged in a regular pattern to form an N-sided polygon on the surface of the substrate.
15 . The lamp of claim 14 wherein the one or more photodetectors include N photodetectors.
16 . The lamp of claim 15 wherein each of the N photodetectors is disposed external to the N-sided polygon formed by the plurality of LEDs, and positioned at the midpoint of a respective one of the sides of the N-sided polygon.
17 . The lamp of claim 15 wherein the plurality of LEDs include a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs.
18 . The lamp of claim 17 wherein the plurality of red LEDs, the plurality of green LEDs, and the plurality of blue LEDs are arranged to form a 3-sided polygon.
19 . The lamp of claim 15 wherein the plurality of LEDs include a plurality of red LEDs, a plurality of green LEDs, a plurality of blue LEDs, and a plurality of white LEDs.
20 . The lamp of claim 19 wherein the plurality of red LEDs, the plurality of green LEDs, the plurality of blue LEDs, and the plurality of white LEDs are arranged to form a 4-sided polygon.