Tunable focus poly(vinyl chloride) gel microlens Array fabricated by shaping in patterned electric field

Abstract

AbstractIn this work, we demonstrate a poly(vinyl chloride) (PVC)‐gel‐based microlens array (MLA) with tunable focus. The MLA is fabricated using a PVC solution and a glass substrate with a ring‐array‐patterned electrode. By coating the solution on the substrate and applying a direct current (DC) voltage to the electrode, a PVC gel membrane with a convex surface profile on the inner region of the electrode (anode) is formed with the solvent evaporation. After the complete evaporation of the solvent and removing the voltage, the solidified PVC gel membrane exhibits an MLA character. When an inverse DC voltage is applied to the electrode, the PVC gel accumulated on the inner region will shift toward the outer electrode connected to the anode, leading the curvature of the convex surface to decrease and the focal length to increase accordingly. The variable surface profile with voltage is precisely measured by a laser confocal microscope and the result shows that the focal length of the MLA can be tuned within a large range.