MEMS-sensor

• US 9,856,133 B2
• Filed: 05/21/2014
• Issued: 01/02/2018
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: Tronics Microsystems S.A. (TDK Corporation)
• Original Assignee: Tronics Microsystems S.A. (TDK Corporation)
• Inventors: Boillot, Franois-Xavier, Laoubi, Rmi
• Primary Examiner(s): SCHMITT, BENJAMIN R
• Application Number:
  US14/891,033
• Publication Number:
  US 20160130133A1
• Time in Patent Office: 1,322 Days
• Field of Search: 7350401, 7350402, 7350408, 7350412, 73510
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81B 3/0048 Constitution or structural means for controlling angular deflection not provided for in groups B81B3/0043 - B81B3/0045
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01C 19/5762 the sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01P 2015/0837 the mass being suspended so as to only allow movement perpendicular to the plane of the substrate, i.e. z-axis sensor

Abstract

A sensor which measures parameters such as acceleration, rotation and magnetic field comprises a substrate defining a plane and at least one sensing plate suspended above the substrate for movement in a sensing direction orthogonal to the substrate plane. A detection arm suspended above the substrate is rotational about an axis parallel to the substrate plane. An out-of-plane coupling structure couples the sensing plate to the detection arm for generating rotational movement of the detection arm, which is detected by a rotation detection structure. A pivot element arranged at a distance from the coupling structure facilitates tilting movement of the sensing plate.

Claims

1. A sensor for measuring physical parameters such as acceleration, rotation, magnetic field, comprising

a) a substrate defining a substrate plane,

b) at least one sensing plate suspended above the substrate for performing a movement having at least a first component in a sensing direction, wherein the sensing direction is orthogonal to the substrate plane,

c) at least one detection arm that is suspended above the substrate for performing a rotational movement about a rotation axis parallel to the substrate plane,

d) an out-of-plane coupling structure for coupling the first component of the movement of said sensing plate to said detection arm for generating the rotational movement of the detection arm,

e) a rotation detection structure cooperating with the detection arm for detecting the rotational movement of the detection arm with respect to the substrate plane,

f) characterized by a pivot element arranged at a distance from the out-of-plane coupling structure, said pivot element coupling the sensing plate to a geometric reference plane, which is at a fixed distance above the substrate, so that the sensing plate performs a tilting out-of-plane movement.

2. The sensor according to claim 1, further comprising a drive mass suspended for performing a movement in a drive direction parallel to the substrate plane and a drive structure for actuating the drive mass in the drive direction.

3. The sensor according to claim 2, wherein the drive mass is coupled to the sensing plate by said pivot element.

4. The sensor according to claim 3, wherein the pivot element is v-shaped and is pointing in a direction perpendicular to the drive direction.

5. The sensor according to claim 3, wherein the pivot element is a flexible sheet-like element.

6. The sensor according to claim 2, wherein the drive mass has the shape of a frame.

7. The sensor according to claim 2, wherein the out-of-plane coupling structure is outside an area encompassed by the drive mass.

8. The sensor according to claim 2, wherein the out-of-plane coupling structure is inside an area encompassed by the drive mass.

9. The sensor according to claim 2, wherein an electrostatic drive unit for generating the drive movement is arranged inside the area encompassed by the detection structure.

10. The sensor according to claim 2, wherein an electrostatic drive unit for generating the drive movement is arranged outside the area encompassed by the drive mass.

11. The sensor according to claim 2, wherein the drive mass is flexibly connected to an anchor arranged outside the area encompassed by the drive mass and inside the area encompassed by the sensing plate.

12. The sensor according to claim 2, wherein the drive mass is flexibly connected to an anchor arranged outside the area encompassed by the drive mass.

13. The sensor according to claim 1, wherein the detection arm is part of a detection structure that has the shape of a frame surrounding the sensing plate.

14. The sensor according to claim 1, wherein the detection arm is arranged in an opening of the sensing plate.

15. The sensor according to claim 1 wherein the sensing plate, the drive mass and the detection arm are symmetric with respect to an axis, which is parallel to the substrate plane and orthogonal to the rotation axis of the detection arm.

16. The sensor according to claim 1, further comprising a second sensing plate, a second out-of-plane coupling structure for coupling the first component of the movement of said second sensing plate to said detection arm for generating the rotational movement of the detection arm.

17. The sensor according to claim 16, further comprising an anti-phase coupling structure for anti-phase coupling of the movement of the at least one sensing plate and the second sensing plate in a drive direction.

18. The sensor according to claim 17, wherein the anti-phase coupling structure is anchored to the substrate.

19. The sensor according to claim 1, wherein the out-of-plane coupling structure is arranged at an outer end of the sensing plate with respect to said rotation axis.

20. The sensor according to claim 1, wherein the rotation detection structure comprises a piezoresistive nano-wire gauge or a resonator gauge.

21. The sensor according to claim 1, wherein the rotation detection structure comprises a flexible layer that functions as a piezoresistive element that transforms the out-of-plane displacement of the detection arm into an electric signal.