Design of illumination optics with extended sources based on wavefront tailoring

So far, illumination optics design for extended sources (like LEDs) has been mainly treated as perturbations of ideal point sources without any extent. Such approaches work well provided that this ideal case is approximately met. However, the demand for very compact luminaires equipped with modern high-brightness LEDs results in configurations where the actual size of the sources cannot be ignored. Here, we develop a wavefront tailoring method producing prescribed illumination patterns while fully encompassing the extended source size. We combine this technique with a wavefront-coupling design scheme, obtaining a powerful tool for creating optics for large Lambertian emitters and prescribed intensity emissions. As an example, we design a highly compact and efficient freeform lens delivering a constant illuminance pattern. Importantly, the presented design strategy can work with various methods for calculating the optical surfaces, such as direct methods or optimization routines. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement