# US 10,371,715 B2 · MEMS accelerometer with proof masses moving in an anti-phase direction

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- Number: US 10,371,715 B2
- Document ID: US10371715B2
- Status: Granted
- Kind: B2
- Application number: 14/642,529
- Filed: 2015-03-09
- Published: 2015-07-09
- Granted: 2019-08-06
- Earliest claimed: 2013-12-23
- Assignees: InvenSense, Inc.
- Applicants: InvenSense, Inc.
- Inventors: Leonardo Baldasarre; Matthew Julian Thompson
- Web page: https://patentgrep.com/patent/US10371715B2

## CPC

- G01P 15/125: by capacitive pick-up
- 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}
- G01P 2015/086: {using a torsional suspension spring}
- G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G})

## Abstract

A sensor is disclosed. The sensor includes a substrate and a mechanical structure. The mechanical structure includes at least two proof masses including a first proof mass and a second proof mass. The mechanical structure also includes a flexible coupling between the at least two proof masses and the substrate. The at least two proof masses move in an anti-phase direction normal to the plane of the substrate in response to acceleration of the sensor normal to the plane and move in anti-phase in a direction parallel to the plane of the substrate in response to an acceleration of the sensor parallel to the plane. The at least two proof masses move in a direction parallel to the plane of the substrate in response to an acceleration of the sensor parallel to the plane.

## Claims

### Claim 1

A sensor comprising:
a substrate; and
a mechanical structure, wherein the mechanical structure includes:
at least two proof masses including a first proof mass and a second proof mass;
a flexible coupling between the at least two proof masses and the substrate; and
a transducer for measuring motion in a direction normal and parallel to a plane of the substrate of the mechanical structure relative to the substrate,
wherein the at least two proof masses move in an anti-phase direction normal to the plane of the substrate in response to acceleration of the sensor normal to the plane and move in anti-phase in a direction parallel to the plane of the substrate in response to an acceleration of the sensor parallel to the plane, and wherein the transducer is a capacitive sensor.

### Claim 2 (depends on 1)

The sensor of claim 1, wherein the first proof mass and the second proof mass have unbalancing torque.

### Claim 3 (depends on 1)

The sensor of claim 1, wherein the flexible coupling further comprises:
at least one anchor; and
a rotational and torsional system, wherein the rotational and torsional system further includes an anchoring spring connecting the at least one anchor, a first rotational lever and a second rotational lever, wherein a first rotational and torsional spring connects the first proof mass to the first rotational lever with a first lever length, and wherein a second rotational and torsional spring connects the second proof mass to the second rotational lever with a second lever length.

### Claim 4 (depends on 3)

The sensor of claim 3, wherein the first lever length and the second lever length are different.

### Claim 5 (depends on 4)

The sensor of claim 4, wherein the flexible coupling further includes:
a second anchoring rotational and torsional spring connecting the at least one anchor and a second rotational and torsional lever;
a third rotational and torsional spring connects the first proof mass to the second rotational lever with a third lever length; and
a fourth rotational and torsional spring connects the second proof mass to the second rotational lever with a fourth lever length,
wherein the first rotational lever and the second rotational lever rotate antiphase in a direction normal to the substrate in response to acceleration of the sensor normal to the substrate, and
wherein the first rotational lever and the second rotational lever rotate antiphase in a plane parallel to the substrate in response to acceleration of the sensor parallel to the substrate.

### Claim 6 (depends on 5)

The sensor of claim 5, wherein the third lever length and the fourth lever length are different.

### Claim 7 (depends on 1)

The sensor of claim 1, further comprising a magnetic material, wherein the magnetic material is on any of the at least two proof masses, the first rotational lever, and the second rotational lever, and wherein the mechanical structure rotates in another plane parallel to the plane in response to the magnetic field in a direction parallel to the plane.

### Claim 8 (depends on 1)

The sensor of claim 1, further comprising a magnetic material, wherein the magnetic material is on any of the at least two proof masses, the first rotational lever, and the second rotational lever, and wherein the mechanical structure rotates in a directional normal to the plane in response to the magnetic field in a direction normal to the plane.

### Claim 9 (depends on 1)

The sensor of claim 1, further comprising a magnetic material, wherein the magnetic material is on any of the at least two proof masses, the first rotational lever, and the second rotational lever.

### Claim 10 (depends on 1)

The sensor of claim 1, wherein the mechanical structure rotates in a directional normal to the plane in response to a magnetic field in a direction normal to the plane.

### Claim 11

A sensor comprising:
a substrate; and
a mechanical structure, wherein the mechanical structure includes:
at least two proof masses including a first proof mass and a second proof mass,
a flexible coupling between the at least two proof masses and the substrate; and
a transducer for measuring motion in a direction normal and parallel to a plane of the substrate of the mechanical structure relative to the substrate,
wherein the at least two proof masses move in an anti-phase direction normal to the plane of the substrate in response to acceleration of the sensor normal to the plane and move in anti-phase in a direction parallel to the plane of the substrate in response to an acceleration of the sensor parallel to the plane,
wherein the at least two proof masses move in a direction parallel to the plane of the substrate in response to an acceleration of the sensor parallel to the plane, and
wherein the transducer is a capacitive sensor.

### Claim 12 (depends on 11)

The sensor of claim 11, wherein the first proof mass and the second proof mass have unbalancing torque.

### Claim 13 (depends on 11)

The sensor of claim 11, wherein the flexible coupling further comprises:
at least one anchor; and
a rotational, translational and torsional system, wherein the rotational, translational and torsional system further including an anchoring spring connecting the at least one anchor, a first rotational lever and a second rotational lever, wherein a first rotational, translational and torsional spring connects the first proof mass to the first rotational torsional lever with a first lever length, and wherein a second rotational, translational and torsional spring connects the second proof mass to the second rotational lever with a second lever length.

### Claim 14 (depends on 13)

The sensor of claim 13, wherein the first lever length and the second lever length are different.

### Claim 15 (depends on 14)

The sensor of claim 14, wherein the flexible coupling further includes:
a second anchoring rotational, translational and torsional spring connecting the at least one anchor and a second rotational, translational and torsional lever;
a third rotational, translational and torsional spring connects the first proof mass to the second rotational, translational and torsional lever with a third lever length; and
a fourth rotational, translational and torsional spring connects the second proof mass to the second rotational, translational and torsional lever with a fourth lever length.

### Claim 16 (depends on 15)

The sensor of claim 15, wherein the third lever length and the fourth lever length are different.

### Claim 17 (depends on 15)

The sensor of claim 15, further comprising magnetic material, wherein the magnetic material is on any of the at least two proof masses, the first rotational lever, and the second rotational lever.

### Claim 18 (depends on 11)

The sensor of claim 11, further comprising a magnetic material, wherein the magnetic material is on any of the at least two proof masses, the first rotational lever, and the second rotational lever, and wherein the mechanical structure rotates in another plane parallel to the plane in response to the magnetic field in a direction parallel to the plane.

### Claim 19 (depends on 11)

The sensor of claim 11, further comprising a magnetic material, wherein the magnetic material is on any of the at least two proof masses, the first rotational lever, and the second rotational lever, and wherein the mechanical structure rotates in a directional normal to the plane in response to the magnetic field in a direction normal to the plane.

### Claim 20 (depends on 11)

The sensor of claim 11, wherein the transducer is on any of the two proof masses, or the mechanical structure, or lever arms associated with the two proof masses.

### Claim 21 (depends on 11)

The sensor of claim 11, wherein the transducer is a capacitive sensor.