From regular periodic micro-lens arrays to randomized continuous phase profiles

Illumination systems for various industrial applications, e.g., in semiconductor industries and medical treatment techniques, require a specific and well-adapted intensity distribution with maximum efficiency, best achievable accuracy, and highest flexibility in the selection of the target light field. Additionally, for particular applications, all these aspects have to be fulfilled simultaneously for different wavelengths. In most of these situations, the challenging optical specifications are accompanied by the requirement of a cost-efficient fabrication technique, suitable at least for batch or small series production. In the present contribution, we first retrace the development steps and performance progress of micro-optical-based beam shaping setups. Secondly, we discuss the possibilities resulting from a combination of both refractive and diffractive optical characteristics. Especially, we show that a well-adapted combination of refractive and diffractive properties in a single element allows us to create achromatic diffusers with exceptional flexibility and high conversion efficiency.