Tailoring high-performance illumination lenses for extended non-Lambertian sources

A key challenge in tailoring compact and high-performance illumination lenses for extended non-Lambertian sources is to take both the étendue and the radiance distribution of an extended non-Lambertian source into account when redirecting the light rays from the source. We develop a direct method to tailor high-performance illumination lenses with prescribed irradiance properties for extended non-Lambertian sources. A relationship between the irradiance distribution on a given observation plane and the radiance distribution of the non-Lambertian source is established. Both edge rays and internal rays emanating from the extended light source are considered in the numerical calculation of lens profiles. Three examples are given to illustrate the effectiveness and characteristics of the proposed method. The results show that the proposed method can yield compact and high-performance illumination systems in both the near field and far field.