Dielectrophoresis formation of ellipsoidal PDMS micro-lens array diagonally aligned on flexible membrane

This paper presents the shaping of polydimethylsiloxane (PDMS) droplet on a flexible polyethylene (PE) membrane and the associated fabrication process of PDMS ellipsoidal micro-lens array (MLA). This design enlarges the viewing field and has better resolution than spherical MLA because the presented MLA is on a curved substrate and the ellipsoidal lens improves images. The PE membrane coated with polytetrafluoroethylene (Teflon^® AF) is covered on a flexible printed circuit (FPC) board. PDMS droplets are dispensed on this membrane. Due to diagonally distributed dielectrophoresis force caused by four-quarter circular electrode pairs, the PDMS droplets deform as part of ellipsoid. Ellipsoidal micro-lens arranging in two orthogonal orientations are created by applying two couples of bias voltage on different electrode pairs. The length of the major axis is different with applied bias voltage. After curing PDMS droplets, the ellipsoidal MLA on flexible membrane is manufactured.