US 12,356,860 B2
Laminated piezoelectric element
Shuto Ono, Tokyo (JP)
Assigned to TDK CORPORATION, Tokyo (JP)
Appl. No. 17/761,265
Filed by TDK Corporation, Tokyo (JP)
PCT Filed Dec. 11, 2020, PCT No. PCT/JP2020/046375
§ 371(c)(1), (2) Date Mar. 17, 2022,
PCT Pub. No. WO2021/125097, PCT Pub. Date Jun. 24, 2021.
Claims priority of application No. 2019-226628 (JP), filed on Dec. 16, 2019.
Prior Publication US 2022/0376163 A1, Nov. 24, 2022
Int. Cl. H10N 30/50 (2023.01); H10N 30/87 (2023.01)
CPC H10N 30/508 (2023.02) [H10N 30/871 (2023.02); H10N 30/872 (2023.02)] 12 Claims
OG exemplary drawing
 
1. A multilayer piezoelectric element, comprising:
a piezoelectric body containing a piezoelectric ceramic material and including a first main surface and a second main surface that oppose to each other;
a first electrode including an external electrode formed on the first main surface; and
a second electrode including an internal electrode formed inside the piezoelectric body to oppose the external electrode,
wherein the piezoelectric body includes an active region between the external electrode and the internal electrode, and includes an inactive region opposite to the active region with the internal electrode interposed therebetween,
a stress received by the piezoelectric body from the external electrode is larger than a stress received by the piezoelectric body from the internal electrode, and
a polarization direction of the active region is a direction directed from the external electrode to the internal electrode.