Design and evaluation of a freeform lens-array for a structured light illumination

Abstract

In illumination applications, freeform lens design starts by modeling the light source intensity, then determining the lens surface. Therefore, any change in the source intensity distribution directly impacts the created illuminance. Freeform lens-array could reduce the dependency between the illuminance pattern and the source intensity distribution. It divides the light source energy into separate beams; each creates the same illuminance pattern. All separated beams are superimposed at a distant target to generate the final illuminance pattern. This paper explains the design procedures of a freeform lens-array in detail, simulates the optical performance, and experimentally evaluates the working principle. Experiments evaluate using different light sources and using a variable illuminated aperture. Moreover, simulations compare the freeform lens-array to a traditional freeform lens.