# US 2026/0096348 A1 · Piezoelectric element and liquid ejection head

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- Number: US 2026/0096348 A1
- Document ID: US20260096348A1
- Status: Published application
- Kind: A1
- Application number: 19/342,868
- Filed: 2025-09-29
- Published: 2026-04-02
- Earliest claimed: 2024-09-30
- Assignees: Seiko Epson Corporation
- Applicants: Seiko Epson Corporation
- Inventors: Nobuo OZAWA; Takatoshi YAMAZAKI; Toshihiro SHIMIZU; Shunsuke YOSHIDA
- Web page: https://patentgrep.com/patent/US20260096348A1

## CPC

- H10N 30/8554: {Lead-zirconium titanate [PZT] based}
- B41J 2/14233: {of film type, deformed by bending and disposed on a diaphragm}
- B41J 2/1646: {thin film formation by sputtering}
- H10N 30/078: by sol-gel deposition
- H10N 30/2047: {Membrane type}
- H10N 30/704: {based on piezoelectric or electrostrictive films or coatings}
- B41J 2002/14241: {having a cover around the piezoelectric thin film element}
- B41J 2002/14258: {Multi layer thin film type piezoelectric element}
- B41J 2002/14419: {Manifold}
- B41J 2202/03: Specific materials used
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS

## Abstract

A piezoelectric element is a piezoelectric element including a piezoelectric layer including a plurality of layers and a pair of electrodes disposed with the piezoelectric layer interposed between the electrodes. The piezoelectric layer is formed of lead zirconate titanate. ΔH is 24% or less when an average value, a maximum value, and a minimum value of a content of hydrogen contained in a plurality of central layers of the piezoelectric layer are defined as H(ave), H(max), and H(min), respectively, and a larger one of absolute values of (H(max)−H(ave))/H(ave)) and (H(min)−H(ave))/H(ave)) is defined as ΔH as a change rate of the content of hydrogen.

## Claims

### Claim 1

A piezoelectric element comprising:
a piezoelectric layer including a plurality of layers; and
a pair of electrodes disposed with the piezoelectric layer interposed between the electrodes, wherein
the piezoelectric layer is formed of lead zirconate titanate, and
ΔH is 24% or less when an average value, a maximum value, and a minimum value of a content of hydrogen contained in a plurality of central layers of the piezoelectric layer are defined as H(ave), H(max), and H(min), respectively, and a larger one of absolute values of (H(max)−H(ave))/H(ave)) and (H(min)−H(ave))/H(ave)) is defined as ΔH as a change rate of the content of hydrogen.

### Claim 2 (depends on 1)

The piezoelectric element according to claim 1, wherein the change rate ΔH is 20% or less.

### Claim 3 (depends on 1)

The piezoelectric element according to claim 1, wherein in the central layers of the piezoelectric layer, an average hydrogen content of a lower layer in a stacking direction is smaller than an average hydrogen content of an upper layer.

### Claim 4 (depends on 1)

The piezoelectric element according to claim 1, wherein in one layer of the central layers of the piezoelectric layer, a hydrogen content on a lower side is larger than a hydrogen content on an upper side.

### Claim 5 (depends on 1)

The piezoelectric element according to claim 1, wherein a film thickness of one central layer of the layers is 100 nm or more and 300 nm or less.

### Claim 6 (depends on 1)

The piezoelectric element according to claim 1, wherein ΔTi is 14% or less when an average value, a maximum value, and a minimum value of a content of titanium contained in the layers are defined as Ti(ave), Ti(max), and Ti(min), respectively, and a larger one of absolute values of (Ti(max)−Ti(ave))/Ti(ave)) and (Ti(min)−Ti(ave))/Ti(ave)) is defined as ΔTi as a change rate of the content of titanium.

### Claim 7 (depends on 2)

The piezoelectric element according to claim 2, wherein ΔTi is 14% or less when an average value, a maximum value, and a minimum value of a content of titanium contained in the layers are defined as Ti(ave), Ti(max), and Ti(min), respectively, and a larger one of absolute values of (Ti(max)−Ti(ave))/Ti(ave)) and (Ti(min)−Ti(ave))/Ti(ave)) is defined as ΔTi as a change rate of the content of titanium.

### Claim 8 (depends on 1)

The piezoelectric element according to claim 1, comprising hydrogen absorption layers at positions interposing the piezoelectric layer between the hydrogen absorption layers in a stacking direction of the layers.

### Claim 9 (depends on 1)

A liquid ejection head comprising the piezoelectric element according to claim 1.