Machine and process development for the robust machining of microstructures on free-form surfaces for hybrid optics

Final report of BMBF collaboration project 'ERANET-OPTICALSTRUCT' Many new developments in optical systems are driven by the quick improvements of LEDs as light source. The LED technology allows for new lighting systems for example in headlights for automotive applications or in miniaturized illumination systems in the field of display technology. In both cases highly sophisticated polymer optics are required to realize these new lighting applications. Often the combination of free-form surfaces with microstructures to hybrid optical systems is necessary. By combining diffractive and refractive functions to hybrid optical systems a high potential of cost saving and light weight design is possible due to the integration of multiple functions into one optical element. The research conducted in the scope of the project 'ERANET-OPTICALSTRUCT' strongly contributed in enabling these new and innovative lighting solutions based on hybrid optics. The aim of the project was to improve the whole process chain starting with the optical design, the flexible machining of molds by diamond cutting, and ending with the manufacturing and characterization of the final product by replication. Beside the replication as final manufacturing step, ultra-precision machining using diamond cutting tools is the key technology for the production of hybrid optics and the corresponding molds. However, the ultra-precision machining systems as well as the process technology needed improvements and a new hybrid Fast Tool Servo system to enable the production of hybrid optics.