# US 10,312,883 B2 · Elastic wave device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,883 B2 - Document ID: US10312883B2 - Status: Granted - Kind: B2 - Application number: 15/233,016 - Filed: 2016-08-10 - Published: 2016-12-01 - Granted: 2019-06-04 - Earliest claimed: 2014-03-14 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Michio Kadota; Tetsuya Kimura; Kenya Hashimoto; Shuji Tanaka - Web page: https://patentgrep.com/patent/US10312883B2 ## CPC - H03H 9/14538: {Formation} - 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 9/02559: {of lithium niobate or lithium-tantalate substrates} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract An elastic wave device includes a first IDT electrode on a first main surface of a LiNbO3 substrate, and a second IDT electrode on a second main surface thereof. The application of alternating voltages with reversed phases to each other to the first and second IDT electrodes excites plate waves in which SH waves in a high order mode predominate. The elastic wave device uses the plate waves in the high order mode in which the SH waves predominate. ## Claims ### Claim 1 An elastic wave device comprising: a LiNbO3 substrate including a first main surface and a second main surface on an opposite side of the first main surface; a first IDT electrode provided on the first main surface of the LiNbO3 substrate; and a second IDT electrode provided on the second main surface of the LiNbO3 substrate so as to be opposed to the first IDT electrode across the LiNbO3 substrate; wherein a plate wave in a high order mode in which an SH wave predominates is excited in the LiNbO3 substrate as an elastic wave in response to alternating voltages of reversed phases to each other being applied to the first IDT electrode and the second IDT electrode. ### Claim 2 (depends on 1) The elastic wave device according to claim 1, wherein in Euler angles (ϕ, θ, ψ) of the LiNbO3 substrate, ϕ=0±5°, ψ=0±5°, and θ is about 72° or more and about 97° or less. ### Claim 3 (depends on 1) The elastic wave device according to claim 1, wherein a thickness of the LiNbO3 substrate is about 0.05λ or more and about 0.52λ or less, and λ represents a wavelength determined by a pitch of electrode fingers of the first and second IDT electrodes. ### Claim 4 (depends on 1) The elastic wave device according to claim 1, wherein a duty of each of the first and second IDT electrodes is about 0.15 or more and about 0.77 or less. ### Claim 5 (depends on 1) The elastic wave device according to claim 1, wherein the first and second IDT electrodes each include an electrode film made of Al or an alloy having Al as a main constituent, and a film thickness of each of the electrode films is about 0.035λ or less, and λ represents a wavelength determined by a pitch of electrode fingers of the first and second IDT electrodes. ### Claim 6 (depends on 1) The elastic wave device according to claim 1, wherein a fractional bandwidth of the elastic wave device is 17% or more. ### Claim 7 (depends on 1) The elastic wave device according to claim 1, wherein a fractional bandwidth of the elastic wave device is 20% or more. ### Claim 8 An elastic wave device comprising: a LiNbO3 substrate including a first main surface and a second main surface on an opposite side of the first main surface; an IDT electrode provided on the first main surface of the LiNbO3 substrate; and an electrode film provided on the second main surface of the LiNbO3 substrate so as to occupy an entire area enclosed with outer edges of the IDT electrode in a plan view from a side of the first main surface; wherein a plate wave in a high order mode in which an SH wave predominates is excited in the LiNbO3 substrate as an elastic wave in response to an alternating voltage being applied to the IDT electrode. ### Claim 9 (depends on 8) The elastic wave device according to claim 8, wherein in Euler angles (ϕ, θ, ψ) of the LiNbO3 substrate, ϕ=0±5°, ψ=0±5°, and θ is about 68° or more and about 96° or less. ### Claim 10 (depends on 8) The elastic wave device according to claim 8, wherein a thickness of the LiNbO3 substrate is about 0.05λ or more and about 0.18λ or less, and λ represents a wavelength determined by a pitch of electrode fingers of the IDT electrode. ### Claim 11 (depends on 8) The elastic wave device according to claim 8, wherein a duty of the IDT electrode is about 0.1 or more and about 0.68 or less. ### Claim 12 (depends on 8) The elastic wave device according to claim 8, wherein the IDT electrode includes an electrode film made of Al or an alloy having Al as a main constituent, and a film thickness of the electrode film is about 0.022λ or less, and λ represents a wavelength determined by a pitch of electrode fingers of the IDT electrode. ### Claim 13 (depends on 8) The elastic wave device according to claim 8, wherein the electrode film defines a floating electrode. ### Claim 14 (depends on 8) The elastic wave device according to claim 8, wherein the electrode film is made of one of Ti, Au, Ni, Cr, and a conductive compound including one of ZnO and ITO. ### Claim 15 (depends on 8) The elastic wave device according to claim 8, wherein a fractional bandwidth of the elastic wave device is 17% or more. ### Claim 16 (depends on 8) The elastic wave device according to claim 8, wherein a fractional bandwidth of the elastic wave device is 20% or more. ### Claim 17 (depends on 8) The elastic wave device according to claim 8, wherein a thickness of the LiNbO3 substrate is about 0.07λ or more and about 0.16λ or less, and λ represents a wavelength determined by a pitch of electrode fingers of the IDT electrode.