Fabrication of Microlens Arrays with High Quality and High Fill Factor by Inkjet Printing
Zhang, Q., Schambach, M., Schlisske, S., Jin, Q., Mertens, A., Hernandez-Sosa, G., Heizmann, M., and Lemmer, U.
Advanced Optical Materials, 2022
Microlens arrays (MLAs) have a variety of applications in, e.g., display systems, projection optics, and sensor applications.
They can be manufactured by various fabrication methods.
Among all, inkjet printing stands out because it offers a simple, fast, and low-cost fabrication route.
However, extra manufacturing steps such as photolithography were so far involved to pre-structure the substrate in order to improve the uniformity of the printed MLAs and achieve a high fill factor.
In this study, we report the fabrication of MLAs on unstructured substrates by inkjet printing using an optimized UV-curable ink on top of self-assembled monolayers (SAMs).
The latter allows for tuning the surface free energy and thus the aspect ratio of the microlenses.
We achieve an unprecedented fill factor of 88%. Digitally controlled large area fabrication is demonstrated, both, on rigid as well as on flexible substrates, opening a pathway for customized microoptics by additive manufacturing.