Development of a Numerical Model for the Luminous Intensity Distribution of a Planar Prism LED Luminaire for Applying an Optimization Algorithm

Abstract

LED lighting is often presented as the lighting technology of the future. Yet there are differences in the luminous intensity distributions between luminaires that employ conventional light sources and those that employ LEDs. The optical engineer faces a new challenge of designing for a spatially extended and nonuniform light source. Consequently, a new approach is needed for the optical design of planar LED luminaires. Luminaire optical design is typically performed using a combination of ray-tracing and trial-and-error experimentation with the goal of obtaining a target luminous intensity distribution. The number of iterations can be reduced by utilizing optimization algorithms. This study aimed to develop a numerical model for luminous intensity distribution of planar prism LED luminaires and apply the optimization algorithm for prism angle design. A calculation process for the prism optical design of a planar prism LED luminaire was developed. To assess the accuracy of the numerical model, a comparison was performed between results from the numerical model and Photopia 2.0. This study also illustrates a method of the application of unit prism angle zones for the control of luminous intensity distributions. As a next step, the numerical model could be extended to optimize prism angle for a target luminous intensity distribution.