Displacement actuation and sensing for an electrostatic drive
First Claim
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1. A method, comprising:
- providing an electrostatic comb drive including a first electrode with several first fingers and a second electrode with several second fingers, the first fingers and the second fingers being interdigitated and spaced apart from one another;
applying an electric drive signal to the electrostatic comb drive, the electric drive signal including an actuation signal constituent and a sensing signal constituent, the sensing signal constituent being in a frequency range above a mechanical resonant frequency of the electrostatic comb device;
in response to the actuation signal constituent, changing displacement of the first electrode relative to the second electrode; and
evaluating the displacement by detecting a change corresponding to a capacitance variation between the first electrode and the second electrode as a function of the sensing signal constituent.
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Abstract
An electrostatic drive includes a first electrode and a second electrode responsive to a drive signal. The drive signal includes an actuation signal constituent and a sensing signal constituent. The sensing signal constituent is at a frequency higher than a natural mechanical resonant frequency of the electrostatic drive. In response to the actuation signal constituent, displacement between the first electrode and the second electrode changes, which is evaluated by detecting a change in an electrical characteristic of the drive as a function of the sensing signal constituent.
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Citations
32 Claims
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1. A method, comprising:
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providing an electrostatic comb drive including a first electrode with several first fingers and a second electrode with several second fingers, the first fingers and the second fingers being interdigitated and spaced apart from one another; applying an electric drive signal to the electrostatic comb drive, the electric drive signal including an actuation signal constituent and a sensing signal constituent, the sensing signal constituent being in a frequency range above a mechanical resonant frequency of the electrostatic comb device; in response to the actuation signal constituent, changing displacement of the first electrode relative to the second electrode; and evaluating the displacement by detecting a change corresponding to a capacitance variation between the first electrode and the second electrode as a function of the sensing signal constituent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus, comprising:
- a microelectromechanical device including;
an electrostatic comb drive including a first electrode with several first fingers and a second electrode with several second fingers, the first fingers and the second fingers being interdigitated and spaced apart from one another; circuitry including; a signal source to generate a electric drive signal with an actuation signal constituent and a sensing signal constituent, the sensing signal constituent being in a frequency range higher than a mechanical resonant frequency of the comb drive; an electrical node to monitor an electrical evaluation signal indicative of displacement of the first electrode relative to the second electrode in response to the drive signal from the signal source; a filter applied to the electrical response to output a response signal selective to the frequency range; and a signal processing circuit to provide an output representative of the displacement in accordance with the response signal. - View Dependent Claims (10, 11, 12, 13)
- a microelectromechanical device including;
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14. An apparatus, comprising:
- a microelectromechanical device including;
a signal source to provide an electric drive signal including a displacement actuation signal constituent and a displacement sensing signal constituent; a linear electrostatic drive including a first electrode and a second electrode spaced apart from the first electrode, the first electrode and the second electrode being responsive to the drive signal to change relative displacement therebetween, the displacement sensing signal constituent being at a frequency range higher than a mechanical resonant frequency of the drive; and circuitry coupled to the drive to monitor electrical response of the linear electrostatic drive to the drive signal, the circuitry being structured to evaluate the displacement by detecting a change corresponding to capacitance variation between the first electrode and the second electrode as a function of the sensing signal constituent and the electrical response. - View Dependent Claims (15, 16, 17, 18, 19)
- a microelectromechanical device including;
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20. A method, comprising:
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supplying a electric drive signal to a linear electrostatic actuator, the electric drive signal including an actuation signal constituent and a sensing signal constituent, the linear electrostatic actuator including a first electrode and a second electrode, the sensing signal constituent being at a frequency higher than a mechanical resonant frequency of the actuator; in response to the actuation signal constituent, displacing the first electrode relative to the second electrode; and detecting the displacing of the first electrode, which includes determining one or more of a change in magnitude and a change in phase of an evaluation signal relative to the sensing signal constituent. - View Dependent Claims (21, 22, 23, 24, 25)
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26. A method, comprising:
- operating a microelectromechanical electrostatic actuator to selectively adjust mechanical state of a device operatively coupled to the actuator, the actuator including a first electrode and a second electrode, at least one of the first electrode and the second electrode being mechanically coupled to the device, the operating of the actuator including;
supplying an electric drive signal simultaneously including an electrostatic drive signal constituent and a sensing signal constituent, the sensing signal constituent being at a frequency higher than a mechanical resonant frequency of the actuator; detecting displacement between the first electrode and the second electrode in response to the electrostatic drive signal constituent, which includes determining one or more of a change in magnitude and a change in phase of an evaluation signal relative to the sensing signal constituent as the electric drive signal is applied to cause the displacement; and changing the mechanical state of the device in response to the displacement. - View Dependent Claims (27, 28, 29, 30, 31, 32)
- operating a microelectromechanical electrostatic actuator to selectively adjust mechanical state of a device operatively coupled to the actuator, the actuator including a first electrode and a second electrode, at least one of the first electrode and the second electrode being mechanically coupled to the device, the operating of the actuator including;
Specification