A new optimization method of freeform surface lens based on non-imaging optics for led source

An optimization method in the design of freeform surface lens based on non-imaging optics to achieve uniform illumination for LED source is proposed. In this design, regular quadratic curve is used as the initial model, and the Scheme programming language and the optimization engine in the TracePro software are used in combination to achieve the control and optimization of local freeform curve. A Lambert emission of 1mm × 1 mm LED is used as simulation source. Three kinds of freeform surface lenses are investigated. It is shown that the uniformity is respectively 97%, 96% and 95% within the field of view of ±14°, ±30° and ±12° at the target surface 1 m away from the source. The energy efficiency is respectively 80.9%, 86.7% and 89.2% for the three lenses. Compared with current traditional optimization methods, the illumination uniformity and energy efficiency are improved significantly. It also possesses advantages of simplicity in process, less reliability on initial model, less optimization time, and good versatility.