Efficient color mixing through étendue conservation using freeform optics

Simone Sorgato; Rubén Mohedano; Julio Chaves; Aleksandra Cvetkovic; Maikel Hernández; Pablo Benitez; Juan C. Miñano; Hugo Thienpont; Fabian Duerr

doi:10.1117/12.2186965

25 August 2015 Efficient color mixing through étendue conservation using freeform optics

Simone Sorgato, Rubén Mohedano, Julio Chaves, Aleksandra Cvetkovic, Maikel Hernández, Pablo Benitez, Juan C. Miñano, Hugo Thienpont, Fabian Duerr

Author Affiliations +

Proceedings Volume 9572, Nonimaging Optics: Efficient Design for Illumination and Solar Concentration XII; 95720G (2015) https://doi.org/10.1117/12.2186965
Event: SPIE Optical Engineering + Applications, 2015, San Diego, California, United States

Abstract

Today’s SSL illumination market shows a clear trend to high flux packages with higher efficiency and higher CRI, realized by means of multiple color chips and phosphors. Such light sources require the optics to provide both near- and far-field color mixing. This design problem is particularly challenging for collimated luminaries, since traditional diffusers cannot be employed without enlarging the exit aperture and reducing brightness. Furthermore, diffusers compromise the light output ratio (efficiency) of the lamps to which they are applied. A solution, based on Köhler integration, consisting of a spherical cap comprising spherical microlenses on both its interior and exterior sides was presented in 2012. The diameter of this so-called Shell-Mixer was 3 times that of the chip array footprint. A new version of the Shell-Mixer, based on the Edge Ray Principle and conservation of etendue, where neither the outer shape of the cap nor the surfaces of the lenses are constrained to spheres or 2D Cartesian ovals will be shown in this work. The new shell is freeform, only twice as large as the original chip-array and equals the original model in terms of color uniformity, brightness and efficiency.

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Simone Sorgato, Rubén Mohedano, Julio Chaves, Aleksandra Cvetkovic, Maikel Hernández, Pablo Benitez, Juan C. Miñano, Hugo Thienpont, and Fabian Duerr "Efficient color mixing through étendue conservation using freeform optics", Proc. SPIE 9572, Nonimaging Optics: Efficient Design for Illumination and Solar Concentration XII, 95720G (25 August 2015); https://doi.org/10.1117/12.2186965

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