MEMS sensor compensation for off-axis movement

Patent metadata

Field	Value
Publication number	US-10766764-B2
Application number	US-201916538166-A
Country	US
Kind code	B2
Filing date	Aug 12, 2019
Priority date	Nov 13, 2017
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A microelectromechanical system (MEMS) sensor includes a MEMS layer that includes fixed and movable electrodes. In response to an in-plane linear acceleration, the movable electrodes move with respect to the fixed electrodes, and acceleration is determined based on the resulting change in capacitance. A plurality of auxiliary electrodes are located on a substrate of the MEMS sensor and below the MEMS layer, such that a capacitance between the MEMS layer and the auxiliary loads changes in response to an out-of-plane movement of the MEMS layer or a portion thereof. The MEMS sensor compensates for the acceleration value based on the capacitance sensed by the auxiliary electrodes.

First claim

What is claimed is:

1. A method for operating a microelectromechanical (MEMS) device, comprising:
applying one or more first potentials to a plurality of movable electrodes of a MEMS layer;
applying one or more second potentials to a plurality of fixed electrodes, wherein each of the plurality of fixed electrodes is located adjacent to at least one of the plurality of movable electrodes in at least a portion of the MEMS layer, wherein the movable electrodes move within the MEMS layer relative to the plurality of fixed electrodes in response to a first force in a first direction to generate a sense signal, and wherein the movable electrodes move outside of the MEMS layer relative to a substrate plane facing a lower plane of the MEMS layer in response to a second force in a second direction;
applying one or more third potentials to a plurality of auxiliary electrodes located on a substrate layer;
compensating for a second movement due to the second force based on an auxiliary signal from the auxiliary electrodes; and
generating an output signal representative of the first force based on the sense signal and the compensation.

2. The method of claim 1 , wherein at least one of the third potentials is the same potential as at least one of the second potentials.

3. The method of claim 1 , wherein the plurality of fixed electrodes output the sense signal in response to at least the movement in the first direction.

4. The method of claim 1 , wherein the plurality of movable electrodes output the sense signal in response to at least the movement in the first direction.

5. The method of claim 1 , wherein the compensation is performed by directly combining the sense signal and the auxiliary signal.

6. The method of claim 1 , wherein the compensation is performed by an application-specific integrated circuit.

7. The method of claim 1 , wherein the compensation is performed by a programmable microprocessing unit.

Assignees

• Invensense Inc

Inventors

• Gurin Ilya
• Seeger Joseph
• Thompson Matthew

Classifications

• B81B3/0086 Primary

  Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage · CPC title

• G01P21/00

  Testing or calibrating of apparatus or devices covered by the preceding groups · CPC title

• G01P15/131

  with electrostatic counterbalancing means · CPC title

• G01P15/0802

  Details · CPC title

• B81B2201/0235

  Accelerometers · CPC title