Patent ID: 8411281

Claim:
A Fabry-Perot interferometer comprising: a fixed mirror structure having a fixed mirror in a spectral region; and a movable mirror structure including a movable membrane oppositely spaced from the fixed mirror structure, the membrane having a movable mirror in the spectral region, wherein the membrane has a plurality of springs in a peripheral region outside the spectral region, the plurality of springs being arranged one inside the other around the spectral region, one of the fixed mirror structure and the membrane has a plurality of first electrodes in the peripheral region, the other of the fixed mirror structure and the membrane has at least one second electrode in the peripheral region, the plurality of first electrodes and the at least one second electrode are located opposite to each other to form a plurality of opposing electrode pairs arranged one inside the other around the spectral region, a number of the plurality of springs is equal to a number of the plurality of opposing electrode pairs, the plurality of springs has a first spring and a second spring located closer to a center of the membrane than the first spring in a direction from an outer edge of the membrane to the center of the membrane, a spring constant of the second spring is less than a spring constant of the first spring, the plurality of opposing electrode pairs has a first electrode pair and a second electrode pair, a first voltage is applied to the first electrode pair during a first period to generate a first electrostatic force, a second voltage is applied to the second electrode pair during a second period to generate a second electrostatic force, and the first period overlaps the second period so that the membrane is displaced during the overlapping period by both the first electrostatic force and the second electrostatic force.