Patent ID: 6791735
Filing Date: 2004-09-14
Classification: G02B

Abstract:
In a spatial light modulator having a plurality of pixels, an electrostatic actuator associated with a pixel and comprising:a lower electrode; an upper electrode fixed with respect to the lower electrode; a center electrode suspended and actuable between the upper and lower electrodes, and having resiliently-biasing means for restoring the center electrode to a non-actuated first equilibrium position; a mirror operably connected to the center electrode; a first voltage source for providing a first bias voltage across the lower and center electrodes; a second voltage source for providing a second bias voltage across the upper and center electrodes, wherein the first and second bias voltages determine the non-actuated first equilibrium position of the center electrode; and a third voltage source for providing a variable driver voltage across one of the lower/center and upper/center electrode pairs in series with the corresponding first or second bias voltage, for actuating the center electrode to a dynamic second equilibrium position characterized by a displacement response substantially linearly proportional to the variable driver voltage due to the pre-existing bias voltages provided by the first and second voltage sources, whereby the center electrode and the mirror are capable of high-precision positioning.