Electrostatic bimorph actuator
First Claim
1. A microelectrical mechanical actuator, comprising:
- a planar substrate with an anchor secured thereto;
cantilevered flexible bimorph arm secured at one end to the anchor and extending along and over the substrate, the bimorph arm including a distal end opposite the end secured to the anchor;
a substrate electrode secured to and insulated from the substrate and positioned under and in alignment with the bimorph arm;
activation electrical couplings to receive an electrical potential difference between the bimorph arm and the substrate electrode to impart electrostatic attraction between the bimorph arm and the substrate electrode, thereby to activate the actuator;
a memory electrode secured to and insulated from the substrate and positioned under and in alignment with the distal end of the bimorph arm; and
a memory electrical coupling to receive an electrical potential at the memory electrode relative to the bimorph arm to impart electrostatic attraction between the bimorph arm and the memory electrode separately from the potential difference applied between the bimorph arm and the substrate electrode.
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Accused Products
Abstract
An electrostatic bimorph actuator includes a cantilevered flexible bimorph arm that is secured and insulated at one end to a planar substrate. In an electrostatically activated state the bimorph arm is generally parallel to the planar substrate. In a relaxed state, residual stress in the bimorph arm causes its free end to extend out-of-plane from the planar substrate. The actuator includes a substrate electrode that is secured to and insulated from the substrate and positioned under and in alignment with the bimorph arm. An electrical potential difference applied between the bimorph arm and the substrate electrode imparts electrostatic attraction between the bimorph arm and the substrate electrode to activate the actuator. As an exemplary application in which such actuators could be used, a microelectrical mechanical optical display system is described.
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Citations
22 Claims
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1. A microelectrical mechanical actuator, comprising:
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a planar substrate with an anchor secured thereto; cantilevered flexible bimorph arm secured at one end to the anchor and extending along and over the substrate, the bimorph arm including a distal end opposite the end secured to the anchor; a substrate electrode secured to and insulated from the substrate and positioned under and in alignment with the bimorph arm; activation electrical couplings to receive an electrical potential difference between the bimorph arm and the substrate electrode to impart electrostatic attraction between the bimorph arm and the substrate electrode, thereby to activate the actuator; a memory electrode secured to and insulated from the substrate and positioned under and in alignment with the distal end of the bimorph arm; and a memory electrical coupling to receive an electrical potential at the memory electrode relative to the bimorph arm to impart electrostatic attraction between the bimorph arm and the memory electrode separately from the potential difference applied between the bimorph arm and the substrate electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. In a microelectrical mechanical actuator formed on a planar semiconductor substrate, the improvement comprising:
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a cantilevered flexible bimorph arm that is secured to the planar substrate and selectively positionable in an relaxed state and in an electrostatically activated state, the bimorph arm being generally parallel to the planar substrate in the electrostatically activated state and extending out-of-plane from the planar substrate in the relaxed state, the bimorph arm being secured at one end to an anchor that is secured to the substrate, the bimorph arm including a length from the end secured to the anchor to a distal end; a memory electrode secured to the substrate and positioned under and in alignment with the distal end of the bimorph arm; and a memory electrical coupling to receive an electrical potential at the memory electrode relative to the bimorph arm to impart electrostatic attraction between the bimorph arm and the memory electrode to maintain the bimorph arm in the activated state. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A microelectrical mechanical actuator array, comprising:
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a plurality of electrostatic bimorph microelectrical mechanical actuators that each have cantilevered flexible bimorph arm that is secured to a planar substrate and selectively positionable in an activated state and in a relaxed state, the bimorph arm being generally parallel to the planar substrate in the activated state and extending out-of-plane from the planar substrate in the relaxed state, each bimorph arm being secured at one end to the substrate and including a length from the end secured to the substrate to a distal end; a substrate electrode secured to the substrate and positioned under and in alignment with the bimorph arm of each actuator; activation electrical couplings to apply an electrical potential difference between the bimorph arm and the substrate electrode of each actuator, the electrical potential difference activating each actuator with electrostatic attraction between the bimorph arm and the substrate electrode; a memory electrode secured to the substrate and positioned under and in alignment with the distal end of the bimorph arm; and a memory electrical coupling to receive an electrical potential at the memory electrode relative to the bimorph arm to impart electrostatic attraction between the bimorph arm and the memory electrode to maintain the bimorph arm in the activated state. - View Dependent Claims (17, 18, 19, 20)
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21. A microelectrical mechanical actuator, comprising:
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a planar substrate with an anchor secured thereto; cantilevered flexible bimorph arm secured at one end to the anchor and extending along and over the substrate; a substrate electrode secured to and insulated from the substrate and positioned under and in alignment with the bimorph arm; activation electrical couplings to receive an electrical potential difference between the bimorph arm and the substrate electrode to impart electrostatic attraction between the bimorph arm and the substrate electrode, thereby to activate the actuator; plural substrate electrodes secured to the substrate and positioned under and in alignment with the bimorph arm; and plural stand-off dimples extending between the bimorph arm and the substrate to hold the bimorph arm in spaced-apart relation to the substrate when the actuator is activated, the plural stand-off dimples being interdigitated with the plural substrate electrodes when the actuator is activated.
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22. In a microelectrical mechanical actuator formed on a planar semiconductor substrate, the improvement comprising:
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a cantilevered flexible bimorph arm that is secured to the planar substrate and selectively positionable in a relaxed state and in an electrostatically activated state, the bimorph arm being generally parallel to the planar substrate in the electrostatically activated state and extending out-of-plane from the planar substrate in the relaxed state; plural spaced-apart substrate electrodes secured to the substrate and positioned under and in alignment with the bimorph arm; and plural stand-off dimples extending between the bimorph arm and the substrate to hold the bimorph arm in spaced-apart relation to the substrate when the actuator is activated, the plural stand-off dimples being interdigitated with the plural substrate electrodes when the actuator is activated.
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Specification