US 11,683,019 B2
Surface acoustic wave device
Naoto Matsuoka, Saitama (JP); Makiko Nakamura, Saitama (JP); and Susumu Yoshimoto, Saitama (JP)
Assigned to NDK SAW Devices Co., Ltd., Hokkaido (JP)
Filed by NDK SAW Devices Co., Ltd., Hokkaido (JP)
Filed on Nov. 15, 2019, as Appl. No. 16/684,607.
Claims priority of application No. JP2018-215986 (JP), filed on Nov. 16, 2018.
Prior Publication US 2020/0162052 A1, May 21, 2020
Int. Cl. H03H 9/02 (2006.01); H03H 3/08 (2006.01); H03H 9/145 (2006.01); H03H 9/25 (2006.01)
CPC H03H 9/02535 (2013.01) [H03H 3/08 (2013.01); H03H 9/1452 (2013.01); H03H 9/1457 (2013.01); H03H 9/14552 (2013.01); H03H 9/25 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A surface acoustic wave device, comprising:
a piezoelectric substrate; and
a pair of interdigital transducer electrodes, including:
a pair of busbars, provided on the piezoelectric substrate, and
a plurality of electrode fingers, mutually extending into a comb shape from the respective busbar towards the opposed busbar,
wherein the pair of interdigital transducer electrodes includes an alternating region as a region where the electrode fingers connected to one busbar and the electrode fingers connected to the other busbar are alternately provided, when viewed along an arranged direction of the plurality of electrode fingers,
wherein when a region on an end portion side of the alternating region and a region including distal end portions of the plurality of electrode fingers is referred to as an edge region, a propagation velocity of a surface acoustic wave in the edge region is slower than a propagation velocity of a surface acoustic wave in the alternating region, and
a propagation velocity of a surface acoustic wave in a busbar region as a region where the pair of busbars are disposed is faster than the propagation velocity of the surface acoustic wave in the alternating region;
wherein a thickness of a metal film that constitutes the pair of busbars is thinner than a thickness of a metal film that constitutes the electrode finger to make the propagation velocity of the surface acoustic wave in the busbar region faster than the propagation velocity of the surface acoustic wave in the alternating region.