Designation of freeform lenses for multiple light sources

Optical lenses with freeform surfaces possess good flexibility for design to generate diverse profiles of uniform illumination. However, most of the previous design formulation was applicable only for a single light source without offset. The formulation is extended for the applicability for multiple sources. The proposed approach requires designation of a freeform surface for multiple sources. The weighted least-square technique is introduced as a suboptimal solution to the problem. The proposed approach forms a two-parameter solution space for designation of illumination uniformity and profile fitting. Rectangular illumination of a single source as well as multiple sources is studied. The adequacy of the extended formulation and applicability for uniform illumination is demonstrated by simulation.