Two-dimensional micromechanical actuator with multiple-plane comb electrodes

Abstract

A micro-electro-mechanical actuator consists of a first semiconductor layer comprising a movable element with comb electrodes, a support element with inner and outer comb electrodes and a stationary element with comb electrodes, an electrical insulation layer, and a second semiconductor layer with a cavity to allow out-of-plane rotation of the movable and support elements. The movable element is mounted to the support element by a first pair of torsional hinges whereas the support element is mounted to the stationary element by a second pair of torsional hinges such that the actuator is in gimbaled structure. Inner comb electrodes of the support element interdigitate with comb electrodes of the movable element, and outer comb electrodes of the support element interdigitate with comb electrodes of the stationary element in the same plane defined by the first semiconductor layer to form in-plane comb-drive actuators. The in-plane comb-drive actuator may be controlled to generate two-dimensional oscillation of the movable element about the two axes defined by the torsional hinges. The second semiconductor layer may further comprise comb electrodes which interdigitate vertically with outer comb electrodes of support element to form vertical comb-drive actuators. Combing the in-plane and the vertical comb-drive actuators, the movable element is controllable to perform two-dimensional raster scan motion.