Design and fabrication of an electrohydrodynamically actuated microlens with areal density modulated electrodes

In this paper, we introduce an electrode design for electrohydrodynamically actuated liquid microlenses. The effective electrode areal density radially increases which results in centering of the liquid tunable microlens with a planar device structure. A model was developed to demonstrate the centering mechanism of the liquid microlens. 3D electrostatic simulation was conducted and validity of the idea was examined. A simple fabrication process that uses readily available SU-8 as the insulator was developed and surface modified, hydrophobic SU-8 layer was used to construct the microlens. Focal length of the microlens was measured to vary from 10.1 mm to 5.8 mm as the voltage varied from zero to 100 V.