# US 9,431,994 B2 · Piezoelectric resonator including an adjusting magnet

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- Number: US 9,431,994 B2
- Document ID: US9431994B2
- Status: Granted
- Kind: B2
- Application number: 14/371,417
- Filed: 2013-02-08
- Published: 2014-11-06
- Granted: 2016-08-30
- Earliest claimed: 2012-02-16
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Corporation
- Inventors: Hidenori Katsumura; Hiroshi Kagata
- Web page: https://patentgrep.com/patent/US9431994B2

## CPC

- H03H 9/17: having a single resonator (crystal tuning forks H03H9/21)
- H02N 2/188: {adapted for resonant operation}
- H10N 30/304: {Beam type}
- H10N 30/306: {Cantilevers}
- H03H 2009/02165: {Tuning}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

A piezoelectric resonator including a base part, a first support part fixed to the base part, a beam part fixed to the first support part, a weight part fixed to the beam part, a drive unit provided on the beam part, and an adjusting magnet movable on a main surface of the base part. Furthermore, the weight part is formed of a magnet or a magnetic body, and the beam part extends in a direction along the main surface of the base part. With this configuration, displacement of the resonance frequency generated due to variation in a manufacturing process can be adjusted easily. Even when the resonance frequency is displaced from desired resonance frequency due to variation in the manufacturing process of a power generating element, the displacement can be easily adjusted and maximum efficiency can be obtained.

## Claims

### Claim 1

A piezoelectric resonator comprising:
a base part;
a first support part fixed to the base part;
a beam part fixed to the first support part;
a weight part fixed to the beam part;
a drive unit provided on the beam part; and
an adjusting magnet movable on a main surface of the base part along a direction different from a direction connecting the adjusting magnet and the weight part,
wherein the weight part is formed of a magnet or a magnetic body, and
the beam part extends in a direction along the main surface of the base part.

### Claim 2 (depends on 1)

The piezoelectric resonator of claim 1, wherein the first support part is fixed to a first end portion of the beam part, and the weight part is fixed to a second end portion of the beam part.

### Claim 3 (depends on 2)

The piezoelectric resonator of claim 2, wherein the adjusting magnet is movable along a central axis of the beam part.

### Claim 4 (depends on 1)

The piezoelectric resonator of claim 1, further comprising a second support part,
wherein the first support part is fixed to a first end of the beam part, the second support part is fixed to a second end of the beam part, and the weight part is fixed to a center portion of the beam part.

### Claim 5 (depends on 4)

The piezoelectric resonator of claim 4, wherein the adjusting magnet is movable from a position below the weight part along a direction orthogonal to a central axis of the beam part.

### Claim 6 (depends on 1)

The piezoelectric resonator of claim 1, wherein the drive unit includes a lower electrode, a piezoelectric body, and an upper electrode, and
the lower electrode, the piezoelectric body, and the upper electrode are sequentially laminated on the beam part.

### Claim 7 (depends on 1)

The piezoelectric resonator of claim 1, wherein the adjusting magnet is formed of an electromagnet.

### Claim 8 (depends on 1)

The piezoelectric resonator of claim 1, wherein a space between the adjusting magnet and the weight part is adjustable.

### Claim 9 (depends on 1)

The piezoelectric resonator of claim 1, further comprising a stopper, wherein the stopper is disposed on the main surface of the base part, and a height of the stopper is higher than a height of the adjusting magnet.

### Claim 10 (depends on 6)

The piezoelectric resonator of claim 6, wherein the piezoelectric body has a portion exposed from the upper electrode.