Stacked balanced resonators

• US 10,598,491 B2
• Filed: 12/14/2017
• Issued: 03/24/2020
• Est. Priority Date: 12/14/2016
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Najafi, Khalil, Darvishian, Ali
• Primary Examiner(s): Summons, Barbara
• Application Number:
  US15/841,782
• Publication Number:
  US 20180283866A1
• Time in Patent Office: 831 Days
• Field of Search: 333186, 333188
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion
• CPC Class Codes: H03H 2009/0244 Anchor loss
• CPC Class Codes: H03H 9/0023 Balance-unbalance or balance-balance networks
• CPC Class Codes: H03H 9/02259 Driving or detection means
• CPC Class Codes: H03H 9/02362 Folded-flexure
• CPC Class Codes: H03H 9/02409 by application of a DC-bias voltage H03H9/02417 takes precedence
• CPC Class Codes: H03H 9/2405 of microelectro-mechanical resonators

Abstract

A resonator array comprises substantially paralleled first and second resonant layers having resonating masses. A first set of lateral drive electrodes cause the first resonating mass to vibrate along an axis in a first geometric plane. A second set of lateral drive electrodes cause the second resonating mass to vibrate along an axis in a second geometric plane in an opposite direction of the first resonating mass by about 180 degrees. Rotation in the system causes the masses to vibrate out-of-plane in opposite directions. The opposite vibrational directions of the first and second resonating masses produces a balanced system with small motion in a bonding area between the stacked resonators. As a result, there is minimal propagation of mechanical waves from the balanced system to a substrate resulting in lower anchor loss and a high Q-factor.

Claims

1. A resonator, comprising:

a first resonant mass spatially separated from a first support structure and movably coupled by at least one elastic member at an anchor point to the first support structure, where the first resonant mass has a longitudinal axis residing in a first geometric plane;

a first set of drive electrodes disposed adjacent to the first resonant mass along a periphery of the first resonant mass, where the first set of drive electrodes is configured to vibrate the first resonant mass along an axis defining the first geometric plane;

a second resonant mass spatially separated from a second support structure and movably coupled by at least one elastic member at an anchor point to the second support structure, where the second resonant mass has a longitudinal axis residing in a second geometric plane which differs from the first geometric plane but is substantially parallel with the first geometric plane; and

a second set of drive electrodes disposed adjacent to the second resonant mass along a periphery of the second resonant mass, where the second set of drive electrodes is configured to vibrate the second resonant mass along the same axis as the first resonant mass but 180 degrees out-of-phase with movement of the first resonant mass;

wherein the first support structure is a planar body having a cutout therein and the first resonant mass is a planar body arranged in the cutout of the first support structure; and

the second support structure is a planar body having a cutout therein and the second resonant mass is a planar body arranged in the cutout of the second support structure.

2. The resonator of claim 1 wherein the first resonant mass is movably coupled by two or more elastic members at two or more anchor points to the first support structure and the second resonant mass is movably coupled by two or more elastic members at two or more anchor points to the second support structure, such that each anchor point on the first support structure aligns with and is fixedly coupled to a corresponding anchor point on the second support structure.

3. The resonator of claim 2 wherein the first support structure is directly bonded to the second support structure.

4. The resonator of claim 2 wherein the first support structure is bonded to the second support structure using a bonding layer.

5. The resonator of claim 2 wherein the first support structure and the second support structure each have a thickness on the order of 500 μ

m.

6. The resonator of claim 1 wherein the at least one elastic member is further defined as a meander spring.

7. The resonator of claim 1 further comprises

a first set of sense electrodes disposed adjacent to the first resonant mass and configured to sense movement of the first resonant mass;

and

a second set of sense electrodes disposed adjacent to the second resonant mass and configured to sense movement of the second resonant mass.

8. The resonator of claim 1 is incorporated into a gyroscope.

9. A resonator, comprising:

a first resonant mass spatially separated from a first support structure and movably coupled by at least one elastic member at an anchor point to the first support structure, where the first resonant mass has a longitudinal axis residing in a first geometric plane;

a first set of drive electrodes disposed adjacent to the first resonant mass along a periphery of the first resonant mass, where the first set of drive electrodes is configured to vibrate the first resonant mass along an axis defining the first geometric plane;

a second resonant mass spatially separated from a second support structure and movably coupled by at least one elastic member at an anchor point to the second support structure, where the second resonant mass has a longitudinal axis residing in a second geometric plane which differs from the first geometric plane but is substantially parallel with the first geometric plane;

a second set of drive electrodes disposed adjacent to the second resonant mass along a periphery of the second resonant mass, where the second set of drive electrodes is configured to vibrate the second resonant mass along the same axis as the first resonant mass but 180 degrees out-of-phase with movement of the first resonant mass;

a first set of tuning electrodes disposed adjacent to the first resonant mass and configured to generate an electric field that surrounds the first resonant mass and thereby changes natural oscillating frequency of the first resonant mass; and

a second set of tuning electrodes disposed adjacent to the second resonant mass and configured to generate an electric field that surrounds the second resonant mass and thereby changes natural oscillating frequency of the second resonant mass.

10. A resonator, comprising:

a first resonant mass spatially separated from a first support structure and movably coupled by at least one elastic member at an anchor point to the first support structure, where the first resonant mass has a longitudinal axis residing in a first geometric plane;

a first set of drive electrodes disposed adjacent to the first resonant mass along a periphery of the first resonant mass, where the first set of drive electrodes is configured to vibrate the first resonant mass along an axis defining the first geometric plane;

a second resonant mass spatially separated from a second support structure and movably coupled by at least one elastic member at an anchor point to the second support structure, where the second resonant mass has a longitudinal axis residing in a second geometric plane which is spatially offset from the first geometric plane; and

a second set of drive electrodes disposed adjacent to the second resonant mass along a periphery of the second resonant mass, where the second set of drive electrodes is configured to vibrate the second resonant mass along the same axis as the first resonant mass but 180 degrees out-of-phase with movement of the first resonant mass

wherein the first geometric plane is substantially parallel with the second geometric plane and the first resonant mass overlays the second resonant mass such that each anchor point on the first support structure is fixedly coupled to a corresponding anchor point on the second support structure;

wherein the first support structure is a planar body having a cutout therein and the first resonant mass is a planar body arranged in the cutout of the first support structure; and

the second support structure is a planar body having a cutout therein and the second resonant mass is a planar body arranged in the cutout of the second support structure.

11. The resonator of claim 10 wherein the first resonant mass is movably coupled by four elastic members at four anchor points to the first support structure and the second resonant mass is movably coupled by four elastic members at four anchor points to the second support structure.

12. The resonator of claim 11 wherein first support structure is directly bonded to the second support structure.

13. The resonator of claim 12 wherein the first support structure and the second support structure each have a thickness on the order of 500 μ

m.

14. The resonator of claim 10 wherein the at least one elastic member is further defined as a meander spring.

15. The resonator of claim 10 further comprises

a first set of sense electrodes disposed adjacent to the first resonant mass and configured to sense movement of the first resonant mass;

and

a second set of sense electrodes disposed adjacent to the second resonant mass and configured to sense movement of the second resonant mass.

16. The resonator of claim 10 is incorporated into a gyroscope.

17. A resonator, comprising:

a first resonant mass spatially separated from a first support structure and movably coupled by at least one elastic member at an anchor point to the first support structure, where the first resonant mass has a longitudinal axis residing in a first geometric plane;

a first set of drive electrodes disposed adjacent to the first resonant mass along a periphery of the first resonant mass, where the first set of drive electrodes is configured to vibrate the first resonant mass along an axis defining the first geometric plane;

a second resonant mass spatially separated from a second support structure and movably coupled by at least one elastic member at an anchor point to the second support structure, where the second resonant mass has a longitudinal axis residing in a second geometric plane which is spatially offset from the first geometric plane;

a second set of drive electrodes disposed adjacent to the second resonant mass along a periphery of the second resonant mass, where the second set of drive electrodes is configured to vibrate the second resonant mass along the same axis as the first resonant mass but 180 degrees out-of-phase with movement of the first resonant mass

wherein the first geometric plane is substantially parallel with the second geometric plane and the first resonant mass overlays the second resonant mass such that each anchor point on the first support structure is fixedly coupled to a corresponding anchor point on the second support structure;

a first set of tuning electrodes disposed adjacent to the first resonant mass and configured to generate an electric field that surrounds the first resonant mass and thereby changes natural oscillating frequency of the first resonant mass; and

a second set of tuning electrodes disposed adjacent to the second resonant mass and configured to generate an electric field that surrounds the second resonant mass and thereby changes natural oscillating frequency of the second resonant mass.