Numerical optimization strategy for multi-lens imaging systems containing freeform surfaces
With progress in freeform technology, freeform components are entering real system designs. Although freeform surfaces increase the degrees of freedom of systems, optimization strategies for placing multiple freeforms are still underdeveloped. We therefore investigated strategies for placing freeforms to achieve significant improvement in system performance for optical imaging systems. For demonstrating our findings and supporting our observations, we have chosen a Scheimpflug system and a lithography system. Several aspects are investigated and implemented in optimization strategies. These strategies are used to optimize and demonstrate the performance on selected examples, i.e., multi-lens imaging systems containing one or two freeforms. Finally, we describe a workflow to guide the design process from start to the end for implementing freeforms in order to achieve improved system performance.