# US 7,608,981 B2 · Piezoelectric thin film vibrator and fabrication method thereof, driving apparatus and piezoelectric motor using the same

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- Number: US 7,608,981 B2
- Document ID: US7608981B2
- Status: Granted
- Kind: B2
- Application number: 11/447,024
- Filed: 2006-06-06
- Published: 2006-12-21
- Granted: 2009-10-27
- Earliest claimed: 2005-06-15
- Assignees: TDK Corporation
- Inventors: Ken Unno; Kenichi Tochi; Masahiro Miyazaki
- Web page: https://patentgrep.com/patent/US7608981B2

## CPC

- H02N 2/166: {Motors with disc stator}
- Y10T 29/42: Piezoelectric device making
- H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The invention relates to a piezoelectric thin film vibrator having a piezoelectric device formed by using thin film formation technology, a fabrication method thereof, a driving apparatus and a piezoelectric motor using the same, and an object is to provide a piezoelectric thin film vibrator which can provide an excellent piezoelectric characteristic at low cost, a fabrication method thereof, a driving apparatus and a piezoelectric motor using the same. A piezoelectric thin film vibrator is configured to have a resonator which generates a flexure traveling wave, a lower electrode which is formed on the resonator, a piezoelectric thin film which is formed by epitaxial growth on the lower electrode, and a plurality of upper electrode parts which is formed on the piezoelectric thin film.

## Claims

### Claim 1

A piezoelectric thin film vibrator comprising:
a resonator for generating a traveling wave;
a first electrode disposed on the resonator;
a piezoelectric thin film disposed on the first electrode; and
a plurality of second electrodes disposed on the piezoelectric thin film,
wherein a crystal orientation of the piezoelectric thin film is aligned to be normal to a crystal orientation of the first electrode.

### Claim 2 (depends on 1)

The piezoelectric thin film vibrator according to claim 1, wherein the piezoelectric thin film is formed of lead zirconate titanate.

### Claim 3 (depends on 1)

The piezoelectric thin film vibrator according to claim 1, wherein the resonator is formed of monocrystalline silicon.

### Claim 4 (depends on 1)

The piezoelectric thin film vibrator according to claim 1, wherein the plurality of the second electrodes is arranged in a segment of circle.

### Claim 5 (depends on 4)

The piezoelectric thin film vibrator according to claim 4, wherein the shape of the plurality of the second electrodes is a fan shape.

### Claim 6 (depends on 4)

The piezoelectric thin film vibrator according to claim 4, wherein the shape of the plurality of the second electrodes is a trapezoidal shape.

### Claim 7 (depends on 4)

The piezoelectric thin film vibrator according to claim 4, wherein the shape of the plurality of the second electrodes is a rectangular shape.

### Claim 8 (depends on 1)

A driving apparatus comprising:
the piezoelectric thin film vibrator according to claim 1; and
an alternating current power source which applies alternating voltages to the plurality of the second electrodes, wherein phases of the alternating voltages are shifted by a half cycle between adjacent electrodes of the plurality of the second electrodes.

### Claim 9 (depends on 8)

A piezoelectric motor comprising:
a stator which has the driving apparatus according to claim 8; and
a rotor which is disposed on the piezoelectric thin film vibrator.

### Claim 10

A piezoelectric thin film vibrator comprising:
a resonator for generating a traveling wave;
a first electrode disposed on the resonator;
a piezoelectric thin film disposed on the first electrode; and
a plurality of second electrodes arranged in a segment of a circle on the piezoelectric thin film,
wherein one of the second electrodes is electrically connected to a lead electrode that is formed on an outer perimeter side of the circle and another one of the second electrodes adjacent to the one of the second electrodes is electrically connected to a lead electrode that is formed on an inner perimeter side of the circle.

### Claim 11 (depends on 10)

The piezoelectric thin film vibrator according to claim 10, wherein a phantom line that extends from a center of the piezoelectric thin film vibrator in the radial direction and divides the one of the second electrodes in equal halves and a phantom line that divides the another one of the second electrodes adjacent to the one of the second electrodes into equal halves form an angle θa of about π/5 radians.

### Claim 12 (depends on 11)

The piezoelectric thin film vibrator according to claim 11, wherein the phantom line that divides the one of the second electrodes into equal halves and a phantom line that divides yet another one of the second electrode adjacent to the one of the second electrodes into equal halves form an angle θb of about 3π/10 radians.