US 12,471,496 B2
Piezoelectric film comprising a polymer-based piezoelectric composite material providing satisfactory acoustic characteristic and durability
Yoshinori Tamada, Minamiashigara (JP)
Assigned to FUJIFILM Corporation, Tokyo (JP)
Filed by FUJIFILM Corporation, Tokyo (JP)
Filed on Aug. 5, 2022, as Appl. No. 17/882,174.
Application 17/882,174 is a continuation of application No. PCT/JP2021/000659, filed on Jan. 12, 2021.
Claims priority of application No. 2020-019505 (JP), filed on Feb. 7, 2020.
Prior Publication US 2022/0384706 A1, Dec. 1, 2022
Int. Cl. H10N 30/87 (2023.01); H10N 30/857 (2023.01)
CPC H10N 30/874 (2023.02) [H10N 30/857 (2023.02)] 20 Claims
OG exemplary drawing
 
1. A piezoelectric film comprising:
a polymer-based piezoelectric composite material which contains piezoelectric particles in a matrix containing a polymer material; and
electrode layers which are provided on both surfaces of the polymer-based piezoelectric composite material,
wherein in a case where a cross section of the piezoelectric film in a thickness direction is observed with a scanning electron microscope, the polymer-based piezoelectric composite material is divided into ten equal regions in the thickness direction, area ratios of the piezoelectric particles in two most distant regions are measured, and the area ratio of the piezoelectric particles in the region with a lower area ratio is set as 1, the area ratio of the piezoelectric particles in the region with a higher area ratio is 1.2 or greater.