Design and application of flexible insert for microinjection compression molding polymer microlens arrays with tunable height

Abstract

A flexible insert is assembled using easily available porous plate and flexible polymer film. Then, applying microinjection compression molding technology, a fast and efficient method is proposed for successive, mass and one‐step replication of polymer microlens arrays (MLAs). Orderly MLAs with convex microlenses are successfully prepared without a given micro‐feature on the insert corresponding to that on the MLAs. Interestingly, the flexible films are deformed to arc‐like profiles that match with the shape of the microlenses with different curvatures under the action of different mold compression forces. Hence, by only changing the compression force, a series of high quality MLAs with tunable height and so geometrical‐morphology are molded by one flexible insert. The molded MLAs exhibit average heights of 61.61–86.28 µm by varying the compression force from 90 to 120 kN. The molded MLAs exhibit favorable geometrical‐morphology uniformity and optical properties. The proposed method is an accessible approach to avoid expensive equipment and complicated procedure for manufacturing the mold microfeature. POLYM. ENG. SCI., 58:213–219, 2018. © 2017 Society of Plastics Engineers