Acceleration and angular velocity resonant detection integrated structure, and related MEMS sensor device

Patent metadata

Field	Value
Publication number	US-9989364-B2
Application number	US-201615192404-A
Country	US
Kind code	B2
Filing date	Jun 24, 2016
Priority date	Sep 28, 2012
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

An integrated detection structure has a first inertial mass and a second inertial mass, each of which is elastically anchored to a substrate and has a linear movement along a first horizontal axis, a first detection movement of rotation about a first axis of rotation parallel to a second horizontal axis and a second detection movement of translation along the second horizontal axis; driving electrodes cause linear movement of the inertial masses, in opposite directions of the first horizontal axis; a pair of flexural resonator elements and a pair of torsional resonator elements are elastically coupled to the inertial masses, the torsional resonator elements having a resonant movement of rotation about a second axis of rotation and a third axis of rotation, parallel to one another and to the first axis of rotation.

First claim

The invention claimed is:

1. An integrated detection structure comprising:
a substrate;
first, second, and third anchors coupled to the substrate;
first and second elastic elements coupled to the first and second anchors;
a movable mass suspended over the substrate and coupled to the first and second anchors by the first and second elastic elements;
a first resonator element having a first end coupled to the first elastic element and a second end coupled to the third anchor, the first resonator element being elastically coupled to the movable mass by the first elastic element;
a second resonator element having a first end coupled to the second elastic element and a second end coupled to the third anchor, the second resonator element being elastically coupled to the movable mass by the second elastic element; and
a set of drive electrodes configured to drive the movable mass to move in a first plane and to drive the first and second resonator elements to resonate at a first natural resonance frequency, wherein the first and second resonator elements are configured to resonate at a second natural resonance frequency that is different than the first natural resonance frequency in response to the integrated detection structure being rotated.

2. The integrated detection structure of claim 1 , wherein the first and second resonator elements are flexural resonator elements configured to resonate at the second natural resonance frequency in response to the structure being rotated about an axis that is perpendicular to a plane of the movable mass.

3. The integrated detection structure of claim 1 , wherein the movable mass is a first movable mass and the set of drive electrodes is a first set of drive electrodes, the integrated detection structure, further comprising:
third, fourth, and fifth anchors coupled to the substrate;
third and fourth elastic elements coupled to the third and fourth anchors;
a second movable mass suspended over the substrate and coupled to the third and fourth anchors by the third and fourth elastic elements;
a third resonator element having a first end coupled to the third elastic element and a second end coupled to the fifth anchor, the third resonator element being elastically coupled to the second movable mass by the third elastic element;
a fourth resonator element having a first end coupled to the fourth elastic element and a second end coupled to the fifth anchor, the fourth resonator element being elastically coupled to the second movable mass by the fourth elastic element; and
a second set of drive electrodes configured to drive the second movable mass to move in a first plane and to drive the third and fourth resonator elements to resonate at the first natural resonance frequency, wherein the third and fourth resonator elements are configured to resonate at the second natural resonance frequency that is different than the first natural resonance frequency in response to the integrated detection structure being rotated.

4. The integrated detection structure of claim 1 , further comprising:
first and second elastic supporting elements; and
a pair of resonator elements elastically coupled to the movable mass by the first and second elastic supporting elements, respectively, the first and second elastic supporting elements being configured to enable independent resonant movements of the pair resonator element with respect to the substrate.

5. The integrated detection structure of claim 4 , wherein each resonator element of the pair of resonator elements is in an opening in the movable mass.

6. The integrated detection structure of claim 4 , wherein the pair of resonator elements are torsional resonator elements that are configured to resonate at a third frequency, when the integrated detection structure is rotated about an axis that is in the first plane, the pair of resonator elements are configured to resonate at a fourth frequency.

7. The integrated detection structure of claim 1 , wherein the first and second resonator elements are arranged linearly with respect to each other.

8. The integrated detection structure of claim 1 , further comprising first and second detection electrodes coupled to the substrate and operatively coupled to the first and second resonator elements, respectively, to enable detection of the first and second natural resonance frequencies.

9. The integrated detection structure of claim 8 , wherein the first and second resonator elements resonate at various resonance frequencies as electrical stiffness of the first and second resonator elements varies.

10. An integrated detection structure comprising:
a substrate;
elastic anchorage elements;
an inertial mass coupled to the substrate by the elastic anchorage elements;
a first set of driving electrodes operatively coupled to the inertial mass and configured to drive the inertial mass;
first and second elastic supporting elements; and
a pair of resonator elements elastically coupled to the inertial mass by the first and second elastic supporting elements, respectively, the first and second elastic supporting elements being configured to enable independent resonant movements of the pair of resonator elements with respect to the substrate,
wherein the elastic anchorage elements are configured to allow the inertial mass to have a linear driving movement along a first axis, allow a first detection movement of rotation about a first rotation axis that is transverse to the first axis as a function of a first angular velocity or a first linear acceleration to be detected and cause corresponding variations of resonance frequency of the pair of resonator elements.

11. The integrated detection structure of claim 10 , wherein the first axis is in a plane defined by a surface of the inertial mass.

12. The integrated detection structure of claim 10 , wherein the pair of resonator elements is a torsional resonator element.

13. The integrated detection structure of claim 10 , wherein each of the resonator elements of the pair resonator elements is arranged inside an opening of the inertial mass.

14. The integrated detection structure of claim 10 , wherein the elastic anchorage elements are further configured to allow the inertial mass to perform a linear detection movement.

15. The integrated detection structure of claim 10 , further comprising first and second resonator elements coupled to the elastic anchorage elements, the first second resonator elements arranged along an axis.

16. An electronic device comprising:
an integrated detection structure including:
a substrate;
first elastic anchorage elements;
second elastic anchorage elements;
a first inertial mass suspended over the substrate and coupled to the substrate by the first elastic anchorage elements;
a second inertial mass suspended over the substrate and coupled to the substrate by the second elastic anchorage elements;
driving electrodes operatively coupled to the first and second inertial masses and configured to drive the first and second inertial masses in opposite directions of each other;
a first pair of first resonator elements elastically coupled to the first inertial mass, the first pair of first resonator elements being configured to resonate at a first frequency; and
a second pair of first resonator elements elastically coupled to the second inertial mass, the second pair of first resonator elements being configured to resonate at a second frequency; and
a reading and driving circuit electrically coupled to the integrated detection structure.

17. The electronic apparatus of claim 16 , comp

Assignees

• St Microelectronics Srl

Inventors

• Comi Claudia
• Corigliano Alberto
• Baldasarre Leonardo

Classifications

• G01P2015/0831

  the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration · CPC title

• G01P15/125

  by capacitive pick-up · CPC title

• G01P15/097 Primary

  by vibratory elements · CPC title

• G01C19/574 Primary

  the devices having two sensing masses in anti-phase motion · CPC title

• G01C19/56

  Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces · CPC title