# US 10,478,857 B2 · Piezoelectric transducers using micro-dome arrays

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- Number: US 10,478,857 B2
- Document ID: US10478857B2
- Status: Granted
- Kind: B2
- Application number: 16/013,786
- Filed: 2018-06-20
- Published: 2018-10-18
- Granted: 2019-11-19
- Earliest claimed: 2011-02-15
- Assignees: FUJIFILM Dimatix, Inc.
- Applicants: FUJIFILM Dimatix, Inc.
- Inventors: Andreas Bibl; Hung-fai Stephen Law; Kevin von Essen; Mats G. Ottosson
- Web page: https://patentgrep.com/patent/US10478857B2

## CPC

- B06B 1/0622: {on one surface}
- B06B 1/0207: {Driving circuits (specially adapted for particular applications, see the relevant subclass, e.g. G01; circuits for steering transducer arrays G10K11/34; basic circuits H03)}
- B06B 1/0637: {Spherical array}
- B06B 1/0644: {using a single piezoelectric element (B06B1/0688 takes precedence)}
- G10K 11/32: characterised by the shape of the source
- H10N 30/20: with electrical input and mechanical output, e.g. functioning as actuators or vibrators
- H10N 30/2048: {having non-planar shape}
- H10N 30/704: {based on piezoelectric or electrostrictive films or coatings}
- H10N 30/87: Electrodes or interconnections, e.g. leads or terminals
- B06B 2201/76: Medical, dental
- H10N 30/076: by vapour phase deposition
- B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R)
- G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

An ultrasonic piezoelectric transducer device includes a transducer array consisting of an array of vibrating elements, and a base to which the array of vibrating elements in the transducer array are attached. The base include integrated electrical interconnects for carrying driving signals and sensed signals between the vibrating elements and an external control circuit. The base can be an ASIC wafer that includes integrated circuitry for controlling the driving and processing the sensed signals. The interconnects and control circuits in the base fit substantially within an area below the array of multiple vibrating elements.

## Claims

### Claim 1

A piezoelectric transducer, comprising:
a vibrating element comprising a drive electrode, a reference electrode, and a piezoelectric element disposed between the drive electrode and the reference electrode; and
a base supporting the vibrating element on a first surface of the base and including integrated circuitry electrically connected to the drive electrode and the reference electrode of the vibrating element,
wherein the drive electrode, the reference electrode, and the piezoelectric element each include a respective flexible portion and a respective stationary portion connected to the respective flexible portion,
wherein the flexible portions of the drive electrode, reference electrode, and piezoelectric element are suspended over a same area of the first surface and are curved in a first direction relative to the first surface of the base in the absence of an applied voltage between the drive electrode and the reference electrode,
wherein the flexible portions of the reference electrode, drive electrode, and piezoelectric element deflect in response to a driving voltage applied between the drive electrode and the reference electrode,
wherein the transducer has an exposed outer surface facing a direction pointing from the base to the vibrating element, and the exposed outer surface of the transducer includes an outer surface of the vibrating element or an outer surface of a flexible film covering the outer surface of the vibrating element, and
wherein the exposed outer surface of the transducer device deflects in conformity with the deflection of the flexible portions of the reference electrode, drive electrode, and piezoelectric element,
wherein the base has a cavity formed in the first surface, and the flexible portions of the reference electrode, drive electrode, and piezoelectric element are suspended over the cavity.

### Claim 2 (depends on 1)

The piezoelectric transducer of claim 1, wherein the vibrating element is one of a linear array of substantially identical vibrating elements, and wherein the linear array of vibrating elements are each supported by a respective support over the first surface of the base and electrically connected to circuitry in the base.

### Claim 3 (depends on 1)

The piezoelectric transducer of claim 1, wherein the vibrating element is one of a two dimensional array of substantially identical vibrating elements, and wherein the two-dimensional array of vibrating elements are each supported by a respective support over the first surface of the base and electrically connected to circuitry in the base.

### Claim 4 (depends on 3)

The piezoelectric transducer of claim 3, wherein the two dimensional array is a polygonal array.

### Claim 5 (depends on 3)

The piezoelectric transducer of claim 3, wherein the circuitry in the base is substantially within an area directly below the two dimensional array of vibrating elements.

### Claim 6 (depends on 3)

The piezoelectric transducer of claim 3, wherein the flexible portions of the reference electrode, drive electrode, and piezoelectric element are suspended over the central portion of the support.

### Claim 7 (depends on 6)

The piezoelectric transducer of claim 6, wherein the support is a metal ring that has a first side attached to the first surface of the base, and a second side attached to the respective stationary portion of one of the drive electrode and reference electrode that is positioned closer to the first surface of the base.

### Claim 8 (depends on 6)

The piezoelectric transducer of claim 6, wherein the support is a metal ring formed by eutectically bonding the first surface of the base to the respective stationary portion of one of the drive electrode and reference electrode that is positioned closer to the first surface of the base.

### Claim 9 (depends on 1)

The piezoelectric transducer of claim 1, wherein the drive electrode is positioned closer to the first surface of the base than the reference electrode is.

### Claim 10 (depends on 9)

The piezoelectric transducer of claim 9, wherein the flexible portions of the drive electrode, reference electrode, and piezoelectric element are each curved away from the first surface of the base.

### Claim 11 (depends on 9)

The piezoelectric transducer of claim 9, wherein the flexible portions of the drive electrode, reference electrode, and piezoelectric element are each curved toward the first surface of the base.

### Claim 12 (depends on 9)

The piezoelectric transducer of claim 9, wherein the reference electrode is maintained at earth ground potential during operation.

### Claim 13 (depends on 1)

The piezoelectric transducer of claim 1, wherein the piezoelectric element includes a respective curved portion surrounded by a respective planar portion, and wherein the respective planar portion and a peripheral portion of the respective curved portion of the piezoelectric element form the respective stationary portion of the piezoelectric element.

### Claim 14 (depends on 13)

The piezoelectric transducer of claim 13, wherein the peripheral portion of the respective curved portion of the piezoelectric element has a width of at least 0.5 microns.

### Claim 15 (depends on 13)

The piezoelectric transducer of claim 13, wherein the peripheral portion of the respective curved portion of the piezoelectric element has a width of 0.5 to 10 microns.

### Claim 16 (depends on 13)

The piezoelectric transducer of claim 13, wherein the respective curved portion of the piezoelectric element has thickness between 3 to 6 microns.

### Claim 17 (depends on 13)

The piezoelectric transducer of claim 13, wherein the respective curved portion of the piezoelectric element has a height between 1.5 to 10 microns.

### Claim 18 (depends on 13)

The piezoelectric transducer of claim 13, wherein the respective curved portion of the piezoelectric element has a lateral dimension of 15 to 80 microns in a plane perpendicular to the first direction.

### Claim 19 (depends on 1)

The piezoelectric transducer of claim 1, wherein grain structures of the piezoelectric element are columnar and substantially aligned, and all or substantially all of the columnar grains are locally perpendicular to a surface of the piezoelectric element spanning both the flexible portion and the stationary portion of the piezoelectric element.