Microelectromechanical gyroscope with compensation of quadrature error drift

• US 10,466,052 B2
• Filed: 07/01/2016
• Issued: 11/05/2019
• Est. Priority Date: 10/30/2013
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Valzasina, Carlo, Falorni, Luca Giuseppe
• Primary Examiner(s): Kwok, Helen C
• Application Number:
  US15/201,133
• Publication Number:
  US 20160313123A1
• Time in Patent Office: 1,222 Days
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames

Abstract

A microelectromechanical gyroscope, includes: a supporting body; a first movable mass and a second movable mass, which are oscillatable according to a first driving axis and tiltable about respective a first and second sensing axes and are symmetrically arranged with respect to a center of symmetry; first sensing electrodes and a second sensing electrodes associated with the first and second movable masses and arranged on the supporting body symmetrically with respect to the first and second sensing axis, the first and second movable masses being capacitively coupled to the respective first sensing electrode and to the respective second sensing electrode, a bridge element elastically coupled to respective inner ends of the first movable mass and of the second movable mass and coupled to the supporting body so as to be tiltable about an axis transverse to the first driving axis.

Claims

1. A device, comprising:

a substrate;

a first pair of masses;

a plurality of driving electrodes positioned within each of the masses of the first pair of masses;

a second pair of masses;

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

a plurality of second elastic coupling elements positioned within the second pair of masses;

a plurality of mass anchorages on the substrate and respectively coupled to the second elastic coupling elements;

a first pair of sensing electrodes on the substrate and positioned between the substrate and a first mass of the second pair of masses, the electrodes of the first pair of sensing electrodes being spaced apart from each other by a respective one of the plurality of second elastic coupling elements, a first mass anchorage of the plurality of mass anchorages being positioned between the electrodes of the first pair of sensing electrodes, the electrodes of the first pair of sensing electrodes being spaced apart from each other by the first mass anchorage; and

a second pair of sensing electrodes on the substrate and positioned between the substrate and a second mass of the second pair of masses, the electrodes of the second pair of sensing electrodes being spaced apart from each other by a respective one of the plurality of second elastic coupling elements, a second mass anchorage of the plurality of mass anchorages being positioned between the electrodes of the second pair of sensing electrodes, the electrodes of the second pair of sensing electrodes being spaced apart from each other by the second mass anchorage.

2. The device of claim 1 wherein each of the masses of the first pair and the second pair of masses are trapezoidal.

3. The device of claim 1, further comprising a third pair and a fourth pair of sensing electrodes on the substrate and aligned with the first pair of masses, the electrodes of each of the third pair and the fourth pair of electrodes being spaced from each other by respective ones of the plurality of driving electrodes.

4. The device of claim 1, further comprising a central support and a central anchor that couples the central support to the substrate.

5. The device of claim 4 wherein the central support includes a plurality of extensions that extend into the masses of the first pair and second pair of masses.

6. A device, comprising:

a substrate;

a first, a second, a third, and a fourth mass positioned above the substrate;

a central support structure including a first extension that extends into an opening in the first mass along a first direction, a second extension that extends into an opening in the second mass along a second direction, a third extension that extends into an opening in the third mass along a third direction, and a fourth extension that extends into an opening in the fourth mass along a fourth direction;

a first elastic connection having a first end connected to the first extension and a second end connected to the first mass, the first and second ends of the first elastic connection being aligned with the first extension along the first direction, the first elastic connection including a transverse portion positioned within the opening in the first mass and extending in a direction transverse to the first direction, the transverse portion being connected between the first end and the second end of the first elastic connection and spaced apart from the first mass in the direction transverse to the first direction;

a second elastic connection having a first end connected to the second extension and a second end connected to the second mass, the first and second ends of the second elastic connection being aligned with the second extension along the second direction, the second elastic connection including a transverse portion positioned within the opening in the second mass and extending in a direction transverse to the second direction, the transverse portion being connected between the first end and the second end of the second elastic connection and spaced apart from the second mass in the direction transverse to the second direction;

a third elastic connection having a first end connected to the third extension and a second end connected to the third mass, the first and second ends of the third elastic connection being aligned with the third extension along the third direction, the third elastic connection including a transverse portion positioned within the opening in the third mass and extending in a direction transverse to the third direction, the transverse portion being connected between the first end and the second end of the third elastic connection and spaced apart from the third mass in the direction transverse to the third direction; and

a fourth elastic connection having a first end connected to the fourth extension and a second end connected to the fourth mass, the first and second ends of the fourth elastic connection being aligned with the fourth extension along the fourth direction, the fourth elastic connection including a transverse portion positioned within the opening in the fourth mass and extending in a direction transverse to the fourth direction, the transverse portion being connected between the first end and the second end of the fourth elastic connection and spaced apart from the fourth mass in the direction transverse to the fourth direction.

7. The device of claim 6 wherein the central support structure has a rectangular shape, the first, second, third, and fourth extensions extending from sides of the rectangular shape.

8. The device of claim 7 wherein the first elastic connection is positioned within the opening in the first mass, the second elastic connection is positioned within the opening in the second mass, the third elastic connection is positioned within the opening in the third mass, and the fourth elastic connection is positioned within the opening in the fourth mass.

9. The device of claim 6, further comprising an anchor on the substrate and positioned centrally with respect to the first, second, third, and fourth masses and the central support structure coupled to the anchor.

15. The device of claim 6 wherein the first and second directions are aligned with one another along a first driving axis.

16. The device of claim 15 wherein the third and fourth directions are aligned with one another along a second driving axis.

17. The device of claim 16 wherein the central support structure is independently tiltable about the first driving axis and the second driving axis.

10. A device, comprising:

a first trapezoidal mass;

a first plurality of driving electrodes coupled to the first mass;

a second trapezoidal mass;

a second plurality of driving electrodes coupled to the second mass;

a third trapezoidal mass positioned between the first and second masses;

a fourth trapezoidal mass positioned between the first and second masses;

a plurality of elastic coupling elements coupled to the first, second, third, and fourth masses, the plurality of elastic coupling elements configured to move the third and fourth masses in response to movement of the first and second masses by actuation of the driving electrodes;

a central support structure having a first, a second, a third, and a fourth extension respectively extending along a first, a second, a third, and a fourth direction;

a first elastic connection having a first end connected to the first extension and a second end connected to the first mass, the first and second ends of the first elastic connection being aligned with the first extension along the first direction, the first elastic connection including a transverse portion positioned within an opening in the first mass and extending in a direction transverse to the first direction, the transverse portion being connected between the first end and the second end of the first elastic connection and spaced apart from the first mass in the direction transverse to the first direction;

a second elastic connection having a first end connected to the second extension and a second end connected to the second mass, the first and second ends of the second elastic connection being aligned with the second extension along the second direction, the second elastic connection including a transverse portion positioned within an opening in the second mass and extending in a direction transverse to the second direction, the transverse portion being connected between the first end and the second end of the second elastic connection and spaced apart from the second mass in the direction transverse to the second direction;

a third elastic connection having a first end connected to the third extension and a second end connected to the third mass, the first and second ends of the third elastic connection being aligned with the third extension along the third direction, the third elastic connection including a transverse portion positioned within an opening in the third mass and extending in a direction transverse to the third direction, the transverse portion being connected between the first end and the second end of the third elastic connection and spaced apart from the third mass in the direction transverse to the third direction; and

a fourth elastic connection having a first end connected to the fourth extension and a second end connected to the fourth mass, the first and second ends of the fourth elastic connection being aligned with the fourth extension along the fourth direction, the fourth elastic connection including a transverse portion positioned within an opening in the fourth mass and extending in a direction transverse to the fourth direction, the transverse portion being connected between the first end and the second end of the fourth elastic connection and spaced apart from the fourth mass in the direction transverse to the fourth direction.

11. The device of claim 10 wherein the first plurality of driving electrodes is positioned within the first mass and the second plurality of driving electrodes is positioned within the second mass.

12. The device of claim 10 wherein the central support includes a central rectangular structure around which the first, second, third, and fourth masses are positioned, the first, second, third, and fourth extensions extending from respective sides of the central rectangular structure.

13. The device of claim 12 wherein the first extension extends into the opening in the first mass, the second extension extends into the opening in the second mass, the third extension extends into the opening in the third mass, and the fourth extension extends into the opening in the fourth mass.

14. The device of claim 13 wherein the first elastic connection is positioned within the opening in the first mass, the second elastic connection is positioned within the opening in the second mass, the third elastic connection is positioned within the opening in the third mass, and the fourth elastic connection is positioned within the opening in the fourth mass.

18. The device of claim 10 wherein the first and second directions are collinear with one another along a first driving axis, and the third and fourth directions are collinear with one another along a second driving axis.

19. The device of claim 18 wherein the central support structure is independently tiltable about the first driving axis and the second driving axis.

20. The device of claim 10 wherein the first and second directions are aligned with one another along a first driving axis, and the second and third directions are aligned with one another along a second driving axis.