US 12,334,900 B2
Acoustic wave device
Michio Kadota, Sendai (JP); and Shuji Tanaka, Sendai (JP)
Assigned to TOHOKU UNIVERSITY, Sendai (JP)
Appl. No. 17/801,886
Filed by TOHOKU UNIVERSITY, Sendai (JP)
PCT Filed Feb. 12, 2021, PCT No. PCT/JP2021/005129
§ 371(c)(1), (2) Date Aug. 24, 2022,
PCT Pub. No. WO2021/172032, PCT Pub. Date Sep. 2, 2021.
Claims priority of application No. 2020-034101 (JP), filed on Feb. 28, 2020.
Prior Publication US 2023/0361752 A1, Nov. 9, 2023
Int. Cl. H03H 9/02 (2006.01); H03H 9/145 (2006.01); H03H 9/25 (2006.01)
CPC H03H 9/02574 (2013.01) [H03H 9/145 (2013.01); H03H 9/25 (2013.01)] 15 Claims
OG exemplary drawing
 
1. An acoustic wave device comprising:
a piezoelectric substrate;
an electrode provided in such a way as to be in contact with the piezoelectric substrate; and
an acoustic multilayer film provided in such a way as to be in contact with the piezoelectric substrate and/or the electrode, wherein
the acoustic multilayer film includes an acoustic film composed of a first acoustic impedance film and a second acoustic impedance film which are alternately and continuously stacked in three layers or more and twenty layers or less, the first acoustic impedance film having a lower impedance than the second acoustic impedance film,
the acoustic multilayer film is configured to excite an overtone of resonance characteristics of a surface acoustic wave,
the acoustic wave device uses the overtone, and
a thickness of each of at least three layers of the first acoustic impedance films and the second acoustic impedance films of the acoustic multilayer film is 0.012 to 0.118 wavelength, 0.105 to 0.2 wavelength, or 0.216 to 0.275 wavelength of the surface acoustic wave.