Angular rate sensor with centrally positioned coupling structures

Patent metadata

Field	Value
Publication number	US-11525680-B2
Application number	US-202117178167-A
Country	US
Kind code	B2
Filing date	Feb 17, 2021
Priority date	Feb 17, 2021
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

An angular rate sensor includes first, second, third, and fourth proof masses spaced apart from a surface of a substrate, each of the first, second, third, and fourth proof masses being configured to move along first and second transverse axes parallel to the surface of the substrate. A first coupling structure is interposed between and interconnects the first and second proof masses. A second coupling structure is interposed between and interconnects the second and third proof masses. A third coupling structure is interposed between and interconnects the third and fourth proof masses. A fourth coupling structure is interposed between and interconnects the fourth and first proof masses. The first, second, third, and fourth coupling structures are configured to constrain an in-phase motion of adjacent ones of the first, second, third, and fourth proof masses along the first and second transverse axes.

First claim

What is claimed is:

1. An angular rate sensor comprising:
a substrate having a surface;
first, second, third, and fourth proof masses spaced apart from the surface of the substrate, each of the first, second, third, and fourth proof masses being configured to move along first and second transverse axes parallel to the surface;
a first coupling structure interposed between and interconnecting the first and second proof masses;
a second coupling structure interposed between and interconnecting the second and third proof masses;
a third coupling structure interposed between and interconnecting the third and fourth proof masses; and
a fourth coupling structure interposed between and interconnecting the fourth and first proof masses; and
wherein the first, second, third, and fourth coupling structures are configured to constrain an in-phase motion of adjacent ones of the first, second, third, and fourth proof masses along the first and second transverse axes;
wherein each of the first, second, third, and fourth coupling structures comprises a first coupling portion disposed between first and second compliant structures included in a second coupling portion;
wherein the first coupling portion is configured to constrain the in-phase motion of the adjacent ones of the first, second, third, and fourth proof masses along one of the first and second transverse axes;
wherein the second coupling portion configured to constrain the in-phase motion of the adjacent ones of the first, second, third, and fourth proof masses along the other of the first and second transverse axes;
wherein the first compliant structure is coupled to a first sidewall of one of the first, second, third, and fourth proof masses and is coupled to a second sidewall of another one of the first, second, third, and fourth proof masses, the first and second sidewalls being adjacent to one another and spaced apart from one another by a gap; and
wherein the second compliant structure is coupled to the first sidewall and is coupled to the second sidewall; and
wherein each of the first and second compliant structures comprises:
a first spring section having a first end coupled to the first sidewall, the first spring section being compliant in each of first and second directions parallel to the surface of the substrate;
a second spring section having a second end coupled to the second sidewall, the second spring section being compliant in each of the first and second directions; and
a lever element having a length aligned with the first and second sidewalls, the lever having a first lever end coupled to the first spring section and a second lever end coupled to the second spring section.

2. The angular rate sensor of claim 1 , wherein the first coupling portion comprises:
a pivot structure coupled to a first sidewall of one of the first, second, third, and fourth proof masses and coupled to a second sidewall of another one of the first, second, third, and fourth proof masses, the first and second sidewalls being adjacent to one another and spaced apart from one another by a gap; and
an anchor on the surface of the substrate and located in the gap between the first and second sidewalls, the anchor being coupled to a mid-point of the pivot structure.

3. The angular rate sensor of claim 2 wherein the pivot structure comprises:
a first pivot bar having a first mid-point coupled to the anchor by a first spring, a first end coupled to the first sidewall via a second spring, and a second end coupled to the second sidewall via a third spring; and
a second pivot bar having a second mid-point coupled to the anchor by a fourth spring, a third end coupled to the first sidewall via a fifth spring, and a fourth end coupled to the second sidewall via a sixth spring.

4. The angular rate sensor of claim 2 wherein the pivot structure is configured to move flexibly about the anchor such that opposite ends of the pivot structure are configured to move in opposite directions to enable first and second sidewalls to move past one another in opposing directions.

5. The angular rate sensor of claim 1 wherein the first and second compliant structures are arranged in reflection symmetry relative to an axis of symmetry aligned with the first coupling portion.

6. The angular rate sensor of claim 1 wherein the lever element is configured to rotate such that first and second lever ends are configured to move in opposite directions and first and second spring sections are configured to flex to enable the first and second sidewalls to move in phase opposition relative to one another.

7. The angular rate sensor of claim 1 wherein the first, second, third, and fourth coupling structures constrain the in-phase motion of the adjacent ones of first, second, third, and fourth proof masses in the absence of additional in-phase motion constraining coupling structures outside a boundary of the first, second, third, and fourth proof masses.

8. The angular rate sensor of claim 1 wherein:
the angular rate sensor is sensitive to angular velocity about a third axis oriented perpendicular to the surface of the substrate;
the angular rate sensor further comprises actuators configured to enable drive motion of the first and third proof masses along both of the first and second transverse axes in a first orbital drive direction at a drive frequency and configured to enable drive motion of the second and fourth proof masses along both of the first and second transverse axes in a second orbital drive direction at the drive frequency, the second orbital drive direction being opposite from the first orbital drive direction; and
the drive frequency of the drive motion of the first, second, third, and fourth proof masses is configured to change in response to the angular velocity of the angular rate sensor about the third axis.

9. The angular rate sensor of claim 1 wherein:
the angular rate sensor is sensitive to angular velocity about a third axis oriented perpendicular to the surface of the substrate;
the angular rate sensor further comprises actuators configured to enable drive motion of the first and third proof masses in a first drive direction parallel to the first axis and configured to enable drive motion of the second and fourth proof masses parallel to the first axis and in a second drive direction that is opposite from the first drive direction;
the first and third proof masses are configured to move in a first sense direction parallel to the second axis in response to the angular velocity of the angular rate sensor about the third axis; and
the second and fourth proof masses are configured to move in a second sense direction parallel to the second axis that is opposite from the first sense direction in response to the angular velocity of the angular rate sensor about the third axis.

Assignees

• Nxp Usa Inc

Inventors

• Geisberger Aaron A
• Shao Peng

Classifications

• G01C19/5712 Primary

  the devices involving a micromechanical structure · CPC title

• G01C19/5747

  each sensing mass being connected to a driving mass, e.g. driving frames · CPC title

• G01C19/574 Primary

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