US 12,390,834 B2
Piezoelectric device and acoustic transducer
Shinsuke Ikeuchi, Nagaokakyo (JP); Seiji Umezawa, Nagaokakyo (JP); and Fumiya Kurokawa, Nagaokakyo (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Oct. 22, 2021, as Appl. No. 17/507,846.
Application 17/507,846 is a continuation of application No. PCT/JP2019/051194, filed on Dec. 26, 2019.
Claims priority of application No. 2019-092681 (JP), filed on May 16, 2019.
Prior Publication US 2022/0040737 A1, Feb. 10, 2022
Int. Cl. B06B 1/06 (2006.01)
CPC B06B 1/0666 (2013.01) 16 Claims
OG exemplary drawing
 
1. A piezoelectric device comprising:
a substrate including a first main surface and a second main surface opposite to the first main surface;
a piezoelectric element on the first main surface; and
a cover on the first main surface, covering the piezoelectric element, and being spaced apart from the piezoelectric element on the first main surface side; wherein
the piezoelectric element includes a base portion on the first main surface and having an annular external shape when viewed from the first main surface side and a membrane portion inside the annular base portion when viewed from the first main surface side;
the cover includes a first through hole;
the substrate includes a second through hole facing the membrane portion and extending between the first main surface and the second main surface;
a hole diameter of the second through hole on the second main surface side is larger than a hole diameter of the second through hole on the first main surface side; and
a porous material is provided at least at a portion of the first through hole or at a portion of the second through hole.