Primary optics for efficient high-brightness LED colour mixing

A. Cvetkovic; R. Mohedano; O. Dross; M. Hernandez; P. Benítez; J. C. Miñano; J. Vilaplana; J. Chaves

doi:10.1117/12.931508

11 October 2012 Primary optics for efficient high-brightness LED colour mixing

A. Cvetkovic, R. Mohedano, O. Dross, M. Hernandez, P. Benítez, J. C. Miñano, J. Vilaplana, J. Chaves

Proceedings Volume 8485, Nonimaging Optics: Efficient Design for Illumination and Solar Concentration IX; 84850Q (2012) https://doi.org/10.1117/12.931508
Event: SPIE Optical Engineering + Applications, 2012, San Diego, California, United States

Abstract

In SSL general illumination, there is a clear trend to high flux packages with higher efficiency and higher CRI addressed with the use of multiple color chips and phosphors. However, such light sources require the optics provide color mixing, both in the near-field and far-field. This design problem is specially challenging for collimated luminaries, in which diffusers (which dramatically reduce the brightness) cannot be applied without enlarging the exit aperture too much. In this work we present first injection molded prototypes of a novel primary shell-shaped optics that have microlenses on both sides to provide Köhler integration. This shell is design so when it is placed on top of an inhomogeneous multichip Lambertian LED, creates a highly homogeneous virtual source (i.e, spatially and angularly mixed), also Lambertian, which is located in the same position with only small increment of the size (about 10-20%, so the average brightness is similar to the brightness of the source). This shell-mixer device is very versatile and permits now to use a lens or a reflector secondary optics to collimate the light as desired, without color separation effects. Experimental measurements have shown optical efficiency of the shell of 95%, and highly homogeneous angular intensity distribution of collimated beams, in good agreement with the ray-tracing simulations.

Citation Download Citation

A. Cvetkovic, R. Mohedano, O. Dross, M. Hernandez, P. Benítez, J. C. Miñano, J. Vilaplana, and J. Chaves "Primary optics for efficient high-brightness LED colour mixing", Proc. SPIE 8485, Nonimaging Optics: Efficient Design for Illumination and Solar Concentration IX, 84850Q (11 October 2012); https://doi.org/10.1117/12.931508

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