Large-displacement electrostatic deformable mirror using movable bottom electrodes

We propose a new design of the electrostatically actuated deformable mirror with low voltage operation for adaptive optics especially for scanning laser ophthalmoscopy. By using torsional actuation and allowing the arrayed bottom fixed electrodes moving along vertical direction, the gaps between mirrors and the bottom electrodes keep small so that the electrostatic force is large enough to deform the mirror at low voltage. The operation concept was verified through both conventional and system level finite element analyses. The simulation results of 2-μm-thick and 8-mm square membrane showed over 7 μm deformation in the astigmatism mode at a 70 V actuation.