US 12,249,973 B2
Acoustic wave device, filter, and multiplexer
Koichi Sato, Tokyo (JP); Shinji Yamamoto, Tokyo (JP); Toshio Nishizawa, Tokyo (JP); and Ryohei Komiyama, Tokyo (JP)
Assigned to TAIYO YUDEN CO., LTD., Tokyo (JP)
Filed by TAIYO YUDEN CO., LTD., Tokyo (JP)
Filed on Apr. 19, 2022, as Appl. No. 17/724,346.
Claims priority of application No. 2021-081511 (JP), filed on May 13, 2021.
Prior Publication US 2022/0368307 A1, Nov. 17, 2022
Int. Cl. H03H 9/13 (2006.01); H03H 9/17 (2006.01); H03H 9/70 (2006.01)
CPC H03H 9/13 (2013.01) [H03H 9/17 (2013.01); H03H 9/703 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An acoustic wave device comprising:
a piezoelectric layer;
a pair of comb-shaped electrodes disposed on a first surface of the piezoelectric layer, each of the pair of comb-shaped electrodes including electrode fingers that excite an acoustic wave;
a first insulating layer that is disposed at a second surface side of the piezoelectric layer, and has protruding portions and/or recessed portions on a third surface, which is closer to the piezoelectric layer, of the first insulating layer, each of the protruding portions and/or the recessed portions having a shape in which each of left and right side surfaces has linear slopes inclined at different angles with respect to the first surface of the piezoelectric layer in a cross-sectional view; and
a second insulating layer located between the piezoelectric layer and the first insulating layer and disposed on the third surface, on which the protruding portions and/or the recessed portions are formed, of the first insulating layer.