Color mixing optics having an exit lens comprising an array of lenslets on an interior and exterior side thereof
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. An illumination device comprising:
an exit lens comprising an interior side and an exterior side, wherein the interior side and the exterior side of the exit lens each comprises an array of lenslets;
wherein the array of lenslets formed on the interior side of the exit lens is configured with an identical aperture shape, but different dimensions, than the array of lenslets formed on the exterior side of the exit lens; and
wherein a center of each lenslet of the array of lenslets on the interior side of the exit lens is aligned with a center of a respective lenslet of the array of lenslets on the exterior side of the exit lens.
2. The illumination device as recited in claim 1 , wherein the identical aperture shape of the array of lenslets formed on the interior side and the array of lenslets formed on the exterior side is a polygon having N sides, wherein N is an even number greater than or equal to 4.
3. The illumination device as recited in claim 1 , wherein the array of lenslets formed on the interior side and the array of lenslets formed on the exterior side each comprise a square aperture shape, and wherein an aperture ratio of the lenslets formed on the interior side to the lenslets formed on the exterior side is 4:1.
4. The illumination device as recited in claim 1 , wherein the array of lenslets formed on the interior side and the array of lenslets formed on the exterior side each comprise a hexagonal aperture shape, and wherein an aperture ratio of the lenslets formed on the interior side to the lenslets formed on the exterior side is 3:1.
5. The illumination device as recited in claim 1 , wherein the array of lenslets formed on the interior side and the array of lenslets formed on the exterior side each comprise a circular aperture shape, and wherein an aperture ratio of the lenslets formed on the interior side to the lenslets formed on the exterior side is 3:1 or 4:1.
6. The illumination device as recited in claim 1 , wherein a curvature ratio of the lenslets formed on the interior side to the lenslets formed on the exterior side is within a range of 1:10 to 1:9.
7. The illumination device as recited in claim 1 , wherein the exit lens is formed from a material having a refractive index within a range of about 1.45 to about 1.65.