A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources

We present a simulation procedure based on optical ray-tracing in order to optimize the angular homogeneity of the light emitted from the color conversion element (CCE) in a phosphor conversion-based white LED. The blue LED and the yellow CCE light have rather different emission characteristics; so the geometry of the CCE as well as its phosphor concentration have to be carefully adjusted in order to achieve equal irradiance and/or radiant intensity distributions on a photo-detector surrounding the LED. The simulations identify the optimal CCE geometries and material compositions in order to obtain angular homogeneity for a broad range of color temperatures.