Development of magnetic actuation concepts for 3D-printed micro-optics

• Applicant: Professor Dr. Alois Herkommer
• Subject Area: Microsystems ; Measurement Systems
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 461765984

Extremely miniaturized optical systems and probes offer diverse application potential, especially for technical and medical endoscopy, as well as in the field of optical sensors. The systems should ideally have the same functionality as their macroscopic counterparts, on the one hand with regard to the optical performance, on the other hand mechanical functions are required in which individual components are to be moved. The challenge, however, is the technical implementation of such functions in the micro world, especially in the diameter range below 0.5mm.The relatively young research field of 3D printing of polymer micro-optics using two-photon lithography has proven to be advantageous compared to the prior art, since complex optical and mechanical functionalities can be implemented directly in a monolithic overall design, making assembly superfluous. The basic idea and aim of the application is, to implement very small actuatable optical systems by introducing magnetic liquids into 3D printed structures and move them with the help of external magnetic fields. In view of the relevance to medical technology, the project will initially focus on endoscopy, however applications are also visible in the area of technical sensors.To demonstrate the feasibility within the project, complex imaging optics including mechanics should be printed directly on image-guiding multicore fibers. The structures are filled with magnetic fluid and moved either with the help of external magnetic fields or via micro-coils wound around the fiber. In order to demonstrate the active functionality on the smallest scale, a total system diameter of <0.5mm is aimed for, combined with a maximum motion of 50-150 µm and a positioning accuracy of <2 µm. This should enable translatory and rotary movements, which will later allow for the implementation of autofocus, zoom and pan systems. The advantage of the proposed method is the production of the complete actuated opto-mechanical system in only 2-3 production steps. The underlying 3D printing allows both the optical functionality (printing of aspheres and free-form surfaces) and the mechanical functionality to be individually designed and adapted to the target application.

• DFG Programme: Research Grants