A comprehensive study on the parameters effecting color conversion in phosphor converted white light emitting diodes

Abstract

Due to the light scattering processes that take place within the color conversion elements (CCE) of phosphor converted light-emitting diodes (LEDs) and the rather different emission characteristics of the blue LED and the converted light, which have to be matched by the scattering processes, a better understanding of the underlying physical aspects is indispensable for device optimization. We give, based on optical ray-tracing, a comprehensive survey on the parameters that effect color conversion and light scattering within the CCEs of phosphor converted LEDs. Studies range from variations of the geometrical (height, width) to the compositional (concentration of the phosphor in the matrix material, differences of the refractive indices of the matrix and the phosphor materials, phosphor particle size) parameters and identify their respective impacts on the color temperatures and the luminous efficacies of the respective LEDs.