Anti-stiction electrodes
OwnerRoberto Martini, Matthew Julian Thompson +1inventors
InventorsRoberto Martini, Matthew Julian Thompson, Luca Coronato
Life of this patent
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Abstract
A MEMS accelerometer includes a proof mass that rotates about an in-plane axis in response to a linear acceleration such that a portion of the proof mass moves out of plane along an out-of-plane axis in a direction of a bump stop. When the proof mass becomes stuck to the bump stop, a signal is applied to one or more anti-stiction electrodes in a manner that moves the proof mass along a movement axis in order to release the proof mass from the bump stop.
Claims20
A microelectromechanical system (MEMS) accelerometer, comprising:
- a suspended spring-mass system comprising a proof mass, wherein the proof mass moves in a first mode along a first axis in response to an external linear acceleration;
- a bump stop located below the proof mass along the first axis, wherein the proof mass is capable of moving along the first axis to contact and stick to the bump stop;
- an anti-stiction electrode located adjacent to the proof mass that actuates the proof mass in a second mode along a second axis that is non-parallel to the first axis;
- and
- processing circuitry configured to determine that the proof mass is stuck to the bump stop and to apply a signal to the anti-stiction electrode to cause a movement of the proof mass in the second mode at least until the proof mass releases from the bump stop.
A method of releasing a proof mass of microelectromechanical system (MEMS) accelerometer from a bump stop, comprising:
- determining, by processing circuitry, that a proof mass is stuck to a bump stop, wherein the proof mass moves in a first mode in response to a linear acceleration in a direction of a first axis, wherein the bump stop is located below the proof mass along the first axis, and wherein the proof mass is capable of moving along the first axis to contact and stick to the bump stop;
- and
- applying, by the processing circuitry in response to the determination that the proof mass is stuck to the bump stop, a signal to an anti-stiction electrode to cause a movement of the proof mass in a second mode at least until the proof mass releases from the bump stop, wherein the anti-stiction electrode is located adjacent to the proof mass at a location to cause a movement of the proof mass in the second mode about a second axis that is non-parallel to the first axis when the proof mass is actuated by the anti-stiction electrode.
A microelectromechanical system (MEMS) accelerometer, comprising:
- a suspended spring-mass system comprising a proof mass, wherein the proof mass moves about a first axis in response to an external linear acceleration and in a direction of a second axis that is out-of-plane from the suspended spring-mass system in response to the linear acceleration;
- a bump stop located below the proof mass along the second axis, wherein the proof mass is capable of moving along the second axis to contact and stick to the bump stop;
- an anti-stiction electrode located adjacent to the proof mass that actuates the proof mass in a second mode along a third axis that is non-parallel to the first axis and the second axis;
- and
- processing circuitry configured to determine that the proof mass is stuck to the bump stop and to apply a signal to the anti-stiction electrode to cause a movement of the proof mass in the second mode at least until the proof mass releases from the bump stop.
Dependencies are inferred from the claim text.