Piezoelectric actuator, piezoelectric drive device, robot, electronic component transport apparatus, and printer

Patent metadata

Field	Value
Publication number	US-11329214-B2
Application number	US-201816143555-A
Country	US
Kind code	B2
Filing date	Sep 27, 2018
Priority date	Sep 29, 2017
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

A piezoelectric actuator includes a vibration portion, a support portion that is integrally configured with the vibration portion and supports the vibration portion, and a piezoelectric element that is disposed on the vibration portion. The piezoelectric element includes a piezoelectric film including columnar crystal grains extending in a thickness direction. When a thickness of the piezoelectric film is referred to as T [μm] and an average diameter of the crystal grains in the width direction is referred to as D [μm], T/D is within a range of 10 to 100. The thickness T of the piezoelectric film is larger than or equal to 2 μm. A standard deviation of diameters of the crystal grains in the width direction is less than or equal to 1.8 μm.

First claim

What is claimed is:

1. A piezoelectric actuator comprising:
a vibration portion;
a support portion that is integrally configured with the vibration portion and supports the vibration portion; and
a piezoelectric element that is disposed on the vibration portion, the piezoelectric element being configured with:
a first electrode disposed on the vibration portion;
a first piezoelectric film disposed on the first electrode;
an intermediate film disposed on the first piezoelectric film;
a second piezoelectric film disposed on the intermediate film; and
a second electrode disposed on the second piezoelectric film,

wherein the first and second piezoelectric films include columnar crystal grains extending in a thickness direction of each of the first and second piezoelectric films,
when a thickness of a sum of the first piezoelectric film, the intermediate film, and the second piezoelectric film is referred to as T and an average diameter of the columnar crystal grains in a width direction, which is perpendicular to the thickness direction, is referred to as D, T/D is within a range of 10 to 100,
the thickness of the sum of the first piezoelectric film, the intermediate film, and the second piezoelectric film is larger than or equal to 2 μm,
a standard deviation of diameters of the columnar crystal grains in the width direction is less than or equal to 1.8 μm,
the first and second piezoelectric films are formed of the same material, and a thickness of the second piezoelectric film is larger than a thickness of the first piezoelectric film, and
the intermediate film includes titanium and is configured to reduce diffusion of an electrode component of the first electrode into the second piezoelectric film.

2. The piezoelectric actuator according to claim 1 ,
wherein the thickness of the sum of the first piezoelectric film, the intermediate film, and the second piezoelectric film is within a range of 2 μm to 10 μm.

3. The piezoelectric actuator according to claim 1 ,
wherein the average diameter of the columnar crystal grains in the width direction is within a range of 0.1 μm to 1 μm.

4. The piezoelectric actuator according to claim 1 ,
wherein a thickness of the intermediate film is within a range of 2 nm to 6 nm.

5. The piezoelectric actuator according to claim 1 ,
wherein the thickness of the first piezoelectric film is within a range of 60 nm to 160 nm.

6. A piezoelectric drive device comprising:
the piezoelectric actuator according to claim 1 ; and
a driven member that is driven by a driving force from the piezoelectric actuator.

7. A robot comprising
the piezoelectric actuator according to claim 1 .

8. An electronic component transport apparatus comprising
the piezoelectric actuator according to claim 1 .

9. A printer comprising
the piezoelectric actuator according to claim 1 .

10. The piezoelectric actuator according to claim 1 ,
wherein each of the first and second piezoelectric films is formed of a material having a perovskite type crystal structure and has a (100) orientation ratio which is larger than or equal to 90%.

11. A piezoelectric drive device comprising:
the piezoelectric actuator according to claim 10 ; and
a driven member that is driven by a driving force from the piezoelectric actuator.

12. A robot comprising
the piezoelectric actuator according to claim 10 .

13. An electronic component transport apparatus comprising
the piezoelectric actuator according to claim 10 .

14. A printer comprising
the piezoelectric actuator according to claim 10 .

15. The piezoelectric actuator according to claim 1 ,
wherein a dielectric loss of the first and second piezoelectric films is less than or equal to 2%.

16. A piezoelectric drive device comprising:
the piezoelectric actuator according to claim 15 ; and
a driven member that is driven by a driving force from the piezoelectric actuator.

17. A robot comprising
the piezoelectric actuator according to claim 15 .

18. An electronic component transport apparatus comprising
the piezoelectric actuator according to claim 15 .

Assignees

• Seiko Epson Corp

Inventors

• Kobayashi Tomokazu
• Kishida Mitsumi
• Konishi Akio

Classifications

• B41J2/14274

  of stacked structure type, deformed by compression/extension and disposed on a diaphragm · CPC title

• B41J2002/14258

  Multi layer thin film type piezoelectric element · CPC title

• H02N2/0055

  Supports for driving or driven bodies; Means for pressing driving body against driven body · CPC title

• H02N2/003

  using longitudinal or radial modes combined with bending modes · CPC title

• H02N2/103

  by pressing one or more vibrators against the rotor · CPC title