Micromirror system with electrothermal actuator mechanism
AssigneeTexas Instruments Incorporated
InventorIvan Kmecko
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Abstract
The disclosed embodiments combine an electrothermal actuator system with an electrostatic attraction system, in order to orient bistable micromirrors in digital micromirror devices (DMDs). The micromirror, pivotally supported, can switch between two orientations. While typical DMD systems use electrostatic electrodes to orient the micromirror, stiction forces can restrict micromirror motion, affecting optical performance. The disclosed embodiments use an electrothermal actuation system to mechanically assist the electrodes, overcoming stiction without the need for a high-voltage reset pulse.
Claims28
A device comprising:
- a substrate;
- a micromirror mounted to the substrate in such a way as to pivot between two stable positions;
- an electrostatic actuator in electrical communication with the micromirror in such a way as to allow for electrostatically moving the micromirror between the two stable positions;
- and
- an electrothermal actuator mechanically coupled to the micromirror in such a way as to apply a mechanical force to the micromirror to assist in moving the micromirror between the two stable positions.
A device comprising:
- a substrate;
- a reflective surface;
- a hinge supporting the reflective surface above the substrate in such a way as to allow the reflective surface to pivot between two stable positions;
- two electrostatic attractors, one located on each side of the hinge, and each in electrical communication with the reflective surface in such a way as to allow for electrostatically attracting the reflective surface;
- and
- two electrothermal actuators, each mechanically coupled to the reflective surface on opposite sides of the hinge.
A method for orienting a pivotal, bistable micromirror, using two electrodes in electrical communication with the micromirror and two electrothermal actuators mechanically coupled to the micromirror, the method comprising the steps of:
- applying a constant voltage to the micromirror;
- applying voltage to one electrode in order to electrostatically cause the micromirror to pivot;
- and
- applying current to one electrothermal actuator in order to mechanically assist in pivoting the micromirror.
Dependencies are inferred from the claim text.