US 12,294,353 B2
Acoustic wave element, acoustic wave filter device, and multiplexer
Yohei Konaka, Nagaokakyo (JP); and Katsuya Daimon, Nagaokakyo (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Apr. 13, 2022, as Appl. No. 17/719,522.
Prior Publication US 2023/0336158 A1, Oct. 19, 2023
Int. Cl. H03H 9/64 (2006.01); H03H 9/02 (2006.01); H03H 9/145 (2006.01); H03H 9/25 (2006.01)
CPC H03H 9/6483 (2013.01) [H03H 9/02637 (2013.01); H03H 9/02992 (2013.01); H03H 9/14541 (2013.01); H03H 9/25 (2013.01)] 19 Claims
OG exemplary drawing
 
1. An acoustic wave element that causes a high frequency signal to propagate in a prescribed propagation direction of an acoustic wave, the acoustic wave element comprising:
a substrate including a piezoelectric layer;
an IDT electrode provided on the substrate and including one pair of comb-shaped electrodes which are opposed to each other; and
a reflector provided on the substrate adjacent to the IDT electrode in the propagation direction of the acoustic wave; wherein
each of the comb-shaped electrodes of the pair of comb-shaped electrodes includes:
a plurality of electrode fingers extending in a direction intersecting with the propagation direction of the acoustic wave; and
a busbar electrode connecting respective one ends of the plurality of electrode fingers together;
the reflector includes a plurality of reflector electrode fingers extending in the direction intersecting with the propagation direction of the acoustic wave; and
in a case where IRGAP is an IDT-reflector gap, which is a distance between a center of one of the plurality of electrode fingers located closest to the reflector and a center of one of the plurality of reflector electrode fingers located closest to the IDT electrode in a boundary region between the IDT electrode and the reflector, and λREF is a reflector wave length that is twice a repetition pitch of the plurality of reflector electrode fingers, a ratio of about 0.40≤IRGAP/λREF≤about 0.41 is satisfied; and
the reflector wave length, λREF, is longer than an IDT wave length, λIDT, that is a repetition pitch of the plurality of electrode fingers of the comb-shaped electrode.