Performance improvement of MEMS devices
First Claim
1. A microelectromechanical-systems (MEMS) device, comprising:
- a) a mechanical subsystem including a driven mass, the subsystem having a natural stiffness or a natural damping, wherein the driven mass is at least partly movable or at least partly deformable;
b) an actuator responsive to a time-varying control signal to apply force to the driven mass;
c) a sensing capacitor including a first plate attached to and movable with the driven mass and a second plate substantially fixed in position, wherein a capacitance of the sensing capacitor varies as the driven mass moves;
d) a measurement circuit responsive to the capacitance of the sensing capacitor to provide first and second signals corresponding respectively to a displacement and to a velocity of the driven mass; and
e) a control circuit configured to provide the time-varying control signal to the actuator in response to the first signal or the second signal and in response to a selected parameter, so that a characteristic stiffness or a characteristic damping of the mechanical subsystem is different from the natural stiffness or the natural damping, respectively, while the time-varying control signal is applied to the actuator, wherein the measurement circuit is further configured to provide a third signal corresponding to an acceleration of the mass, the mechanical subsystem has a natural mass, and the control circuit is further configured to provide the time-varying control signal to the actuator in response to the third signal, so that a characteristic mass of the mechanical subsystem is different from the natural mass while the time-varying control signal is applied to the actuator.
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Accused Products
Abstract
A microelectromechanical-systems (MEMS) device includes a driven mass and has a natural stiffness or damping. An actuator applies force to the mass, movement of which is measured by a sensing capacitor. A control circuit operates the actuator per displacement or velocity of the driven mass, so that a characteristic stiffness or damping of the mechanical subsystem is different from the respective natural value. A method of transforming a MEMS device design includes determining an aim performance value of the design and a baseline performance uncertainty of the design, selecting candidate sets of parameter values, determining a candidate, first, and second performance value for each, scoring the candidates, and repeating until one of the candidates satisfies a termination criterion, so the transformed design using that candidate set has the aim performance value and the respective first and second performance values closer to each other than the baseline performance uncertainty.
19 Citations
7 Claims
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1. A microelectromechanical-systems (MEMS) device, comprising:
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a) a mechanical subsystem including a driven mass, the subsystem having a natural stiffness or a natural damping, wherein the driven mass is at least partly movable or at least partly deformable; b) an actuator responsive to a time-varying control signal to apply force to the driven mass; c) a sensing capacitor including a first plate attached to and movable with the driven mass and a second plate substantially fixed in position, wherein a capacitance of the sensing capacitor varies as the driven mass moves; d) a measurement circuit responsive to the capacitance of the sensing capacitor to provide first and second signals corresponding respectively to a displacement and to a velocity of the driven mass; and e) a control circuit configured to provide the time-varying control signal to the actuator in response to the first signal or the second signal and in response to a selected parameter, so that a characteristic stiffness or a characteristic damping of the mechanical subsystem is different from the natural stiffness or the natural damping, respectively, while the time-varying control signal is applied to the actuator, wherein the measurement circuit is further configured to provide a third signal corresponding to an acceleration of the mass, the mechanical subsystem has a natural mass, and the control circuit is further configured to provide the time-varying control signal to the actuator in response to the third signal, so that a characteristic mass of the mechanical subsystem is different from the natural mass while the time-varying control signal is applied to the actuator. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification