Microelectromechanical device incorporating a gyroscope and an accelerometer

• US 10,598,690 B2
• Filed: 12/09/2015
• Issued: 03/24/2020
• Est. Priority Date: 09/12/2011
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Simoni, Barbara, Valzasina, Carlo
• Primary Examiner(s): Macchiarolo, Peter J
• Assistant Examiner(s): Singer, David L
• Application Number:
  US14/964,469
• Publication Number:
  US 20160091528A1
• Time in Patent Office: 1,567 Days
• Field of Search: 7350404, 73511, 7350403, 7350412
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions

Abstract

A microelectromechanical device includes: a supporting structure; two sensing masses, movable with respect to the supporting structure according to a first axis and a respective second axis; a driving device for maintaining the sensing masses in oscillation along the first axis in phase opposition; sensing units for supplying sensing signals indicative of displacements respectively of the sensing masses according to the respective second axis; processing components for combining the sensing signals so as to: in a first sensing mode, amplify effects on the sensing signals of concordant displacements and attenuate effects of discordant displacements of the sensing masses; and in a second sensing mode, amplify effects on the sensing signals of discordant displacements and attenuate effects of concordant displacements of the sensing masses.

Claims

1. A device, comprising:

a substrate;

a plurality of pairs of fixed electrodes on the substrate;

a first pair of masses aligned with each other along a first axis, each of the masses having a first end and a second end;

a second pair of masses aligned with each other along a second axis that is transverse to the first axis, each of the masses having a first end and a second end;

a plurality of elastic coupling elements, each elastic coupling element of the plurality of elastic coupling elements being coupled between the first end of a mass of the first pair of masses and the first end of a mass of the second pair of masses;

a plurality of pairs of elastic suspension elements coupled to the substrate, each of the masses of the first pair and the second pair of masses being coupled to only one of the pairs of elastic suspension elements at a location between the first end and the second end, the location being closer to the second end than the first end and aligned between a respective pair of fixed electrodes, each pair of elastic suspension elements configured to enable linear motion and rotation of the respective mass of the first pair and the second pair of masses around a third axis through the respective pair of elastic suspension elements; and

a plurality of pairs of movable electrodes aligned with the fixed electrodes, each pair of movable electrodes arranged on a side of a respective mass of each of the first and second pairs of masses facing the fixed electrodes, each pair of movable electrodes including a first movable electrode and a second movable electrode, wherein the first movable electrode and the second movable electrode of each pair of the plurality of pairs of movable electrodes are positioned on opposing sides of the third axis of each respective pair of elastic suspension elements with the first and second movable electrodes closer to the second end than the first end of each respective mass.

2. The device of claim 1 further comprising:

a plurality of sensing units, each sensing unit associated with a respective mass of the first and second pairs of masses, each sensing unit including a first pair of electrodes on the substrate.

3. The device of claim 2 wherein each sensing unit further includes a second pair of electrodes on the second end of each mass facing a respective first pair of electrodes.

4. The device of claim 3 wherein the second pair of movable electrodes is interposed between the first pair of electrodes of each sensing unit of the plurality of sensing units.

5. The device of claim 1 wherein the first axis and the second axis intersect in a central area.

6. The device of claim 5 wherein each of the first ends of the first pair of masses and the first ends of the second pair of masses are closer to the central area than each of the second ends of the first pair of masses and the second ends of the second pair of masses, respectively.

7. The device of claim 1 wherein the first pair of masses are configured to be driven and the second pair of masses are configured to move in response to the first pair of masses through the plurality of elastic coupling elements.

8. A device, comprising:

a substrate;

a plurality of pairs of fixed electrodes formed on the substrate;

a first mass, a second mass, a third mass, and a fourth mass, each mass having a first end and a second end, each of the first ends being closer to a central area than each of the second ends, the first, second, third, and fourth mass being arranged in a cross configuration;

a plurality of elastic coupling elements, each elastic coupling element being positioned and coupled between the first ends of adjacent masses;

a plurality of pairs of elastic suspension elements coupled to the substrate and to opposite sides of each mass and positioned at a location closer to the second end than to the first end of each mass, the location spaced apart from the first end and the second end of the respective mass, the respective mass being configured to rotate about a rotation axis through the respective pair of elastic suspension elements, the rotation axis of each respective mass proximate the second end of each respective mass with the first end of each mass positioned proximate one another; and

a plurality of pairs of movable electrodes formed on each of the masses, the movable electrodes aligned with the fixed electrodes, each pair of movable electrodes arranged on a side of a respective mass of each of the first, second, third, and fourth masses facing the fixed electrodes, each pair of movable electrodes including a first movable electrode and a second movable electrode, wherein the first movable electrode and the second movable electrode of each pair of the plurality of pairs of movable electrodes are positioned on opposing sides of the rotation axis of each respective pair of elastic suspension elements with the first and second movable electrodes closer to the second end than the first end of each respective mass.

9. The device of claim 8 wherein each mass includes a sensing unit coupled to the second end of a respective mass and the substrate.

10. The device of claim 9 wherein each sensing unit includes parallel-plate capacitor electrodes.

11. The device of claim 8 wherein the plurality of pairs of fixed electrodes are capacitively coupled to corresponding ones of the plurality of pairs of mobile electrodes.

12. The device of claim 11 wherein the plurality of pairs of fixed electrodes and the plurality of pairs of mobile electrodes are comb-fingered electrodes.

13. The device of claim 8 wherein the plurality of pairs of fixed electrodes are configured to generate sensing signals, the device further comprising:

processing circuitry configured to drive at least one of the first mass, the second mass, the third mass, and the fourth mass, the processing circuitry configured to receive the sensing signals and combine the sensing signals in a first sensing mode and a second sensing mode.

14. A system, comprising:

a first pair of masses aligned with each other along a first axis, each of the masses having a first end and a second end, the first pair of masses being configured to be driven;

a second pair of masses aligned with each other along a second axis that is transverse to the first axis, each of the masses having a first end and a second end;

a plurality of elastic coupling elements, each elastic coupling element of the plurality of elastic coupling elements being coupled between the first end of a mass of the first pair of masses and the first end of the second pair of masses, the second pair of masses being configured to move in response to the first pair of masses through the plurality of elastic coupling elements;

a plurality of pairs of fixed electrodes, each pair of fixed electrodes of the plurality of pairs of fixed electrodes being aligned with a half of each respective mass proximate the second end of each respective mass of the first pair and the second pair of masses, each pair of fixed electrodes of the plurality of pairs of fixed electrodes configured to sense acceleration and rotation of the respective mass;

a plurality of pairs of elastic suspension elements, each of the masses of the first pair and the second pair of masses being coupled to one of the pairs of elastic suspension elements at a location between the first end and the second end, the location being closer to the second end than the first end and aligned between a respective pair of fixed electrodes, each pair of elastic suspension elements configured to enable translational motion along the first axis or the second axis and rotational motion about a third axis through the one of the pairs of elastic suspension elements of the respective mass of the first pair and the second pair of masses, the third axis proximate the second end of each respective mass with the first ends of each mass positioned proximate one another;

a plurality of pairs of movable electrodes on the half of each of the masses on a side of each of the masses facing the plurality of pairs of fixed electrodes, the movable electrodes aligned with the fixed electrodes, the plurality of pairs of fixed electrodes being configured to generate sensing signals, each pair of movable electrodes including a first movable electrode and a second movable electrode arranged on opposing sides of the third axis of the one of the pairs of elastic suspension elements of each respective mass with the first and second movable electrodes closer to the second end than the first end of each respective mass; and

processing circuitry configured to drive the first pair of masses.

15. The system of claim 14 wherein the processing circuitry is configured to receive the sensing signals and combine the sensing signals in a first sensing mode and a second sensing mode.

16. The device of claim 14 further comprising:

a substrate;

a plurality of sensing units, each sensing unit coupled to the second end of a respective mass of the first and second pairs of masses and the substrate.

17. The device of claim 16 wherein the plurality of sensing units includes:

a first plurality of sensing units coupled to the second end of a respective one of the first pair of masses and the substrate and configured to detect displacement of the first pair of masses along the first axis; and

a second plurality of sensing units coupled to the second end of a respective one of the second pair of masses and the substrate and configured to detect displacements along the second axis.

18. The device of claim 14 further comprising:

a plurality of driving units coupled to each of the first pair of masses, the plurality of driving units structured to displace the first pair of masses along the first axis.

19. The device of claim 18 wherein the plurality of driving units are comb-fingered driving units.

20. The device of claim 14 wherein the second pair of masses are configured to move in phase opposition to the first pair of masses through the plurality of elastic coupling elements.