# US 12,191,839 B2 · Acoustic wave device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,191,839 B2
- Document ID: US12191839B2
- Status: Granted
- Kind: B2
- Application number: 17/875,496
- Filed: 2022-07-28
- Published: 2022-11-17
- Granted: 2025-01-07
- Earliest claimed: 2020-02-06
- Assignees: Murata Manufacturing Co., Ltd.
- Applicants: Murata Manufacturing Co., Ltd.
- Inventors: Hideki Iwamoto; Katsuya Daimon; Tetsuya Kimura
- Web page: https://patentgrep.com/patent/US12191839B2

## CPC

- H03H 9/02228: {Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer}
- H03H 9/02574: {of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate}
- H03H 9/02015: {Characteristics of piezoelectric layers, e.g. cutting angles}
- H03H 9/02559: {of lithium niobate or lithium-tantalate substrates}
- H03H 9/14541: {Multilayer finger or busbar electrode}
- H03H 9/02834: {of temperature influence (cut angles H03H9/02543)}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

An acoustic wave device includes a support substrate, a piezoelectric layer, and an IDT electrode. The piezoelectric layer is over the support substrate. The IDT electrode is on the piezoelectric layer, and includes a plurality of electrode fingers. An intersecting width of the plurality of electrode fingers is equal to or smaller than about 5λ.

## Claims

### Claim 1

An acoustic wave device comprising:
a support substrate;
a piezoelectric layer over the support substrate in a thickness direction of the support substrate; and
an IDT electrode on the piezoelectric layer, the IDT electrode including a plurality of electrode fingers; wherein
an intersecting width of the plurality of electrode fingers is equal to or smaller than about 5λ.

### Claim 2 (depends on 1)

The acoustic wave device according to claim 1, wherein the intersecting width of the plurality of electrode fingers is equal to or smaller than about 2λ.

### Claim 3 (depends on 1)

The acoustic wave device according to claim 1, further comprising:
a low acoustic velocity film in which an acoustic velocity of a bulk wave propagating through the low acoustic velocity film is lower than an acoustic velocity of a bulk wave propagating through the piezoelectric layer; wherein
the low acoustic velocity film is between the support substrate and the piezoelectric layer in the thickness direction of the support substrate.

### Claim 4 (depends on 3)

The acoustic wave device according to claim 3, further comprising:
a high acoustic velocity film in which an acoustic velocity of a bulk wave propagating through the high acoustic velocity film is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer; wherein
the high acoustic velocity film is between the support substrate and the low acoustic velocity film in the thickness direction of the support substrate.

### Claim 5 (depends on 3)

The acoustic wave device according to claim 3, wherein the support substrate is a high acoustic velocity support substrate in which an acoustic velocity of a bulk wave propagating through the high acoustic velocity support substrate is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer.

### Claim 6 (depends on 1)

The acoustic wave device according to claim 1, wherein the piezoelectric layer is made of lithium tantalate.

### Claim 7 (depends on 2)

The acoustic wave device according to claim 2, further comprising:
a low acoustic velocity film in which an acoustic velocity of a bulk wave propagating through the low acoustic velocity film is lower than an acoustic velocity of a bulk wave propagating through the piezoelectric layer; wherein
the low acoustic velocity film is between the support substrate and the piezoelectric layer in the thickness direction of the support substrate.

### Claim 8 (depends on 7)

The acoustic wave device according to claim 7, further comprising:
a high acoustic velocity film in which an acoustic velocity of a bulk wave propagating through the high acoustic velocity film is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer; wherein
the high acoustic velocity film is between the support substrate and the low acoustic velocity film in the thickness direction of the support substrate.

### Claim 9 (depends on 7)

The acoustic wave device according to claim 7, wherein the support substrate is a high acoustic velocity support substrate in which an acoustic velocity of a bulk wave propagating through the high acoustic velocity support substrate is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer.

### Claim 10 (depends on 2)

The acoustic wave device according to claim 2, wherein the piezoelectric layer is made of lithium tantalate.

### Claim 11 (depends on 3)

The acoustic wave device according to claim 3, wherein the piezoelectric layer is made of lithium tantalate.

### Claim 12 (depends on 4)

The acoustic wave device according to claim 4, wherein the piezoelectric layer is made of lithium tantalate.

### Claim 13 (depends on 5)

The acoustic wave device according to claim 5, wherein the piezoelectric layer is made of lithium tantalate.

### Claim 14 (depends on 7)

The acoustic wave device according to claim 7, wherein the piezoelectric layer is made of lithium tantalate.

### Claim 15 (depends on 8)

The acoustic wave device according to claim 8, wherein the piezoelectric layer is made of lithium tantalate.

### Claim 16 (depends on 9)

The acoustic wave device according to claim 9, wherein the piezoelectric layer is made of lithium tantalate.