US Patent No. 10,427,981

PIEZOELECTRIC MATERIAL, METHOD OF MANUFACTURING THE SAME, PIEZOELECTRIC ELEMENT, AND PIEZOELECTRIC ELEMENT APPLICATION DEVICE


Patent No. 10,427,981
Issue Date October 01, 2019
Title Piezoelectric Material, Method Of Manufacturing The Same, Piezoelectric Element, And Piezoelectric Element Application Device
Inventorship Koji Sumi, Shiojiri (JP)
Kazuya Kitada, Suwa (JP)
Tomohiro Sakai, Matsumoto (JP)
Yasuaki Hamada, Chino (JP)
Tetsuya Isshiki, Shiojiri (JP)
Satoshi Kimura, Fujimi (JP)
Akio Ito, Matsumoto (JP)
Tsuneo Handa, Shimosuwa (JP)
Assignee Seiko Epson Corporation, (JP)

Claim of US Patent No. 10,427,981

1. A piezoelectric material, containing:a first component which is a rhombohedral crystal in a single composition, in which a Curie temperature is Tc1, and which is composed of a lead-free-system composite oxide having a perovskite-type structure;
a second component which is a crystal other than the rhombohedral crystal in a single composition, in which a Curie temperature Tc2 is lower than Tc1, and which is composed of Li, K, Na, and Nb; and
a third component which is a crystal other than the rhombohedral crystal in a single composition similar to the second component, in which a Curie temperature Tc3 is equal to or higher than Tc1, and which is composed of K, Na, and Nb,
wherein when a molar ratio of the third component to the sum of the second component and the third component is set as ? and ?×Tc3+(1??)×Tc2 is set as Tc4, |Tc4?Tc1| is 50° C. or lower.