Dual-sealed MEMS package with cavity pressure monitoring
AssigneeInvenSense, Inc.
InventorsLuca Coronato, Giacomo Gafforelli, Adolfo Giambastiani
Life of this patent
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Abstract
A microelectromechanical sensor (MEMS) package includes a gyroscope and an accelerometer. The gyroscope is located within a low-pressure cavity that is sealed from an external pressure. The accelerometer is located within a cavity, and the seal for the accelerometer cavity is entirely within the gyroscope cavity. Under normal operating conditions, the accelerometer seal holds the accelerometer cavity at a higher pressure than the pressure of the enclosing gyroscope cavity. In the event that one of the gyroscope seal or the accelerometer seal is broken, the gyroscope senses the change in pressure.
Claims30
A multi-sensor microelectromechanical sensor (MEMS) package, comprising:
- a gyroscope configured to measure angular velocity about one or more axes of rotation, the gyroscope comprising:
- a plurality of gyroscope movable masses;
- one or more drive electrodes to drive one or more of the plurality of gyroscope movable masses, wherein the one or more drive electrodes are driven by a drive voltage;
- and
- one or more gyroscope sense electrodes to sense the movement of one or more of the plurality of gyroscope movable masses based on a sense voltage of the gyroscope sense electrodes;
- an accelerometer configured to measure linear acceleration along one or more axes, the accelerometer comprising:
- one or more accelerometer movable masses;
- and
- one or more accelerometer sense electrodes to sense the movement of the one or more accelerometer movable masses;
- an accelerometer seal ring that encloses the accelerometer, wherein the accelerometer seal ring provides an accelerometer pressure for an accelerometer cavity within the accelerometer seal ring;
- a gyroscope seal ring that encloses the gyroscope and the entirety of the accelerometer seal ring, wherein the gyroscope seal ring provides a gyroscope pressure for a gyroscope cavity within the gyroscope seal ring, and wherein the accelerometer seal ring provides a barrier between the accelerometer pressure and the gyroscope pressure;
- and
- processing circuitry configured to sense a change in pressure within the gyroscope cavity based on at least the drive voltage or the sense voltage, wherein the processing circuitry is configured to modify the operation of the gyroscope or the accelerometer based on the change in pressure.
A method for sensing a change in pressure within a microelectromechanical sensor (MEMS) package, comprising:
- determining one or more angular velocities from a MEMS gyroscope, wherein the MEMS gyroscope is located within a first cavity, wherein the first cavity is enclosed by a first cavity seal, and wherein the first cavity seal provides a barrier between a first cavity pressure within the first cavity and an external pressure;
- determining one or more linear accelerations from a MEMS accelerometer, wherein the MEMS accelerometer is located within a second cavity enclosed by a second cavity seal, and wherein the second cavity seal is located entirely within the first cavity seal to provide a barrier between a second cavity pressure within the second cavity and the first cavity pressure;
- sensing, by the MEMS gyroscope, a change in pressure within the first cavity;
- and
- modifying the operation of the MEMS gyroscope or the MEMS accelerometer based on the change in pressure.
A microelectromechanical sensor (MEMS) package, comprising:
- a first cavity enclosed by a first cavity seal, wherein the first cavity seal provides a barrier between a first cavity pressure within the first cavity and an external pressure;
- a second cavity enclosed by a second cavity seal, wherein the second cavity seal is located entirely within the first cavity seal to provide a barrier between a second cavity pressure within the second cavity and the first cavity pressure;
- a MEMS accelerometer located within the second cavity and configured to measure one or more linear accelerations;
- and
- a MEMS gyroscope located within the first cavity and configured to measure one or more angular velocities;
- and
- processing circuitry configured to sense a change in pressure within the first cavity and to modify the operation of the MEMS gyroscope or the MEMS accelerometer based on the change in pressure.
Dependencies are inferred from the claim text.