# US 11,993,083 B2 · Actuator, liquid discharge head, and liquid discharge apparatus

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- Number: US 11,993,083 B2
- Document ID: US11993083B2
- Status: Granted
- Kind: B2
- Application number: 17/480,155
- Filed: 2021-09-21
- Published: 2022-03-31
- Granted: 2024-05-28
- Earliest claimed: 2020-09-30
- Assignees: Ricoh Company, Ltd.
- Applicants: Toshiaki Masuda
- Inventors: Toshiaki Masuda
- Web page: https://patentgrep.com/patent/US11993083B2

## CPC

- B41J 2/14233: {of film type, deformed by bending and disposed on a diaphragm}
- B41J 2/161: {of film type, deformed by bending and disposed on a diaphragm}
- B41J 2/1623: {bonding and adhesion}
- B41J 2/1628: {dry etching}
- B41J 2/1629: {wet etching}
- B41J 2/1631: {photolithography}
- B41J 2/1632: {machining}
- B41J 2/1642: {thin film formation by CVD [chemical vapor deposition]}
- B41J 2/1643: {thin film formation by plating}
- B41J 2/1645: {thin film formation by spincoating}
- B41J 2/1646: {thin film formation by sputtering}
- H10N 30/2047: {Membrane type}
- H10N 30/708: {Intermediate layers, e.g. barrier, adhesion or growth control buffer layers}
- H10N 30/8554: {Lead-zirconium titanate [PZT] based}
- B41J 2002/14491: {Electrical connection}
- B41J 2202/03: Specific materials used
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

An actuator includes a substrate, a diaphragm over the substrate, a lower electrode over the diaphragm, a lead titanate (PbTiO3) layer over the lower electrode, a piezoelectric body over the PbTiO3 layer, and an upper electrode over the piezoelectric body. The piezoelectric body comprises particles of lead zirconate titanate (PZT). An average diameter of the particles of the PZT is 40 nm or more. The average diameter is measured by capturing an electron backscatter diffraction image of the piezoelectric body in an image area of 20 μm×20 μm, fitting each of the particles in the image area, and determining an average value of diameters of the circles.

## Claims

### Claim 1

An actuator comprising:
a substrate;
a diaphragm over the substrate;
a lower electrode over the diaphragm;
a lead titanate (PbTiO3) layer over the lower electrode;
a piezoelectric body over the PbTiO3 layer, the piezoelectric body comprising particles of lead zirconate titanate (PZT); and
an upper electrode over the piezoelectric body,
wherein an average diameter of the particles of the PZT is 40 or more, where the average diameter is measured by capturing an electron backscatter diffraction image of the piezoelectric body in an image area of 20 μm×20 μm, fitting each of the particles in the image area to a circle, and determining an average value of diameters of the circles, and
the PbTiO3 layer has a thickness of 3 nm or more and 35 nm or less.

### Claim 2 (depends on 1)

The actuator according to claim 1,
wherein the lower electrode comprises platinum.

### Claim 3 (depends on 1)

The actuator according to claim 1,
wherein the piezoelectric body satisfies the following relation:
(100)diffraction intensity/{(100)diffraction intensity+(111)diffraction intensity+(110)diffraction intensity}>0.8,
in measuring orientation intensity by an X-ray diffraction intensity method.

### Claim 4 (depends on 1)

The actuator according to claim 1,
wherein the particles of the PZT have an average diameter of 600 nm or less.

### Claim 5 (depends on 1)

The actuator according to claim 1,
wherein the particles of the PZT have an average diameter of 180 nm or less.

### Claim 6 (depends on 1)

The actuator according to claim 1,
wherein the particles of the PZT have an average diameter of 90 nm or more and 140 nm or less.

### Claim 7 (depends on 1)

A liquid discharge head comprising:
a nozzle from which a liquid is discharged;
a liquid chamber communicating with the nozzle; and
the actuator according to claim 1, configured to pressurize the liquid in the liquid chamber.

### Claim 8 (depends on 7)

A liquid discharge apparatus comprising:
a liquid container configured to contain a liquid;
the liquid discharge head according to claim 7, configured to discharge the liquid;
a carriage on which the liquid discharge head is mounted; and
a main scanning moving mechanism configured to move the carriage in a main scanning direction.

### Claim 9 (depends on 1)

The actuator according to claim 1, wherein the average diameter of the particles of the PZT is 90 nm or more and 180 nm or less, where the average diameter is measured by capturing the electron backscatter diffraction image of the piezoelectric body in the image area of 20 μm×20 μm, fitting each of the particles in the image area to the circle, and determining the average value of diameters of the circles.