F. Kranert
A. Schulze Finkenbrink
M. Hinkelmann
J. Neumann
D. Kracht

Multi-material additive manufacturing based on µ-dispenser technology for tailored polymer micro-optics

Proc. SPIE 12433, Advanced Fabrication Technologies for Micro/Nano Optics and Photonics XVI
78-86
2023
Type: Zeitschriftenaufsatz (non-reviewed)
Abstract
Integrated optics are an innovation driver for a multitude of industrial applications like autonomous driving or point-of-care diagnostics. With the increasing demand for miniaturized, low-cost optical systems, new methods for fabricating tailored graded index micro-optics are required. Additive manufacturing is a promising technology for this not only due to its high design freedom, but also because of the potential for function integration via multi-material printing or the integration into digitized process chains. In fact, additive manufacturing of optical elements has not matured yet due to the requirement to fabricate 3D objects with optical quality. In this contribution, μ-dispenser direct ink writing based on transparent photopolymers is presented that enables the production of multi-material micro-optical elements. It will be shown that the achievable printing resolution for 0D- and 1D-structures is mainly depending on the needle diameter. Mono-material spherical and cylindrical lenses with a geometric dimension in the range of a few micrometers have been successfully fabricated and characterized. The geometric shape fidelity of printed 2D-layers, which suffers from surface tension effects due to the material’s molecular cohesive forces, is optimized by proper printing strategies. In an outlook, the route towards the production of micro-optic, function-integrated 3D GRIN elements is given, by using a mixer module to realize combined and gradable extrusion of two photopolymers.