Planar Liquid Confinement for Optical Centering of Dielectric Liquid Lenses

In this letter, planar liquid confinement structures along with concentric electrodes are proposed for the optical centering of dielectric liquid lenses at the rest state and during actuation. Both the liquid confinement structures and electrodes that are photolithographically fabricated on glass substrates share the same geometric center, thereby minimizing the deviation of the optical axis at all operation modes. Tilt angles of mesa liquid confinement structure are experimentally found to be 0.11deg in maximum and below 0.03deg during actuation for a liquid lens with a droplet of initially 7 mm in diameter.