24 September 2008 Köhler integrators embedded into illumination optics add functionality
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The Köhler illumination concept was originally invented to achieve uniform illumination in microscopy1. Köhler integrators can also be formed by arrays of lenticulations that can be any combination of reflective and/or refractive surfaces, organized in corresponding pairs. Arrays of integrating facets can be arranged not only on flat surfaces but on rotationally symmetric and even freeform surfaces6. Currently flat lenslet arrays are widely applied as homogenizing optics2 for lithography, machine vision illumination, and projection. Adding Köhler facets onto already designed surfaces can improve the optical system performance, while respecting its original function. In general, the optics output can be made somewhat independent of the source characteristics, although at the expense of a slight ètendue dilution or efficiency losses. This work revises the Köhler concept and its application to different kind of optics, ranging from photovoltaic concentrators to automotive LED headlights. In the former, irradiance peaks on the solar cell can be avoided, while preserving high aiming tolerance (acceptance) of the solar concentrator. In the latter, LEDs drawbacks like large source image sizes, source misalignments, ill defined source edges, and low source radiance can be compensated.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
O. Dross, O. Dross, R. Mohedano, R. Mohedano, M. Hernández, M. Hernández, A. Cvetkovic, A. Cvetkovic, J. C. Miñano, J. C. Miñano, P. Benítez, P. Benítez, } "Köhler integrators embedded into illumination optics add functionality", Proc. SPIE 7103, Illumination Optics, 71030G (24 September 2008); doi: 10.1117/12.798111; https://doi.org/10.1117/12.798111

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