Fabrication of a high-fill-factor microlens array using different thermal reflow process

Abstract

Thermal reflow is widely used in the fabrication of microlenses as a simple and low-cost process, which includes the direct contact heating and the upside-down reflow. To compare the difference in the shapes of the microlenses obtained by these two approaches, the cylindrical microstructure arrays obtained rapidly via DMD-based lithography system were used for different thermal reflow processes, and subsequently, two types of high-fill-factor microlens arrays (MLAs) were fabricated and measured in the experiment. Results indicate that the MLAs obtained by these two kinds of thermal reflow have different surface profiles, while these MLAs are good in surface quality because the profile curves of each microlens are very similar and continuous. The comparison results provided in this paper can be used as a reference for selecting the appropriate thermal reflow process for fabrication of other microlenses.