US Patent No. 10,804,876

PIEZOELECTRIC VIBRATING PIECE AND PIEZOELECTRIC DEVICE


Patent No. 10,804,876
Issue Date October 13, 2020
Title Piezoelectric Vibrating Piece And Piezoelectric Device
Inventorship Shigetaka Kaga, Saitama (JP)
Assignee NIHON DEMPA KOGYO CO., LTD., Tokyo (JP)

Claim of US Patent No. 10,804,876

1. A piezoelectric vibrating piece, comprising:a piezoelectric substrate, formed into a flat plate shape and vibrated in a thickness-shear vibration mode;
a first excitation electrode, formed on one principal surface of the piezoelectric substrate; and
a second excitation electrode, formed on another principal surface of the piezoelectric substrate, wherein
the first excitation electrode is formed to entirely have an identical thickness,
the second excitation electrode has a main thickness portion and an inclined portion, the main thickness portion being formed to have a constant thickness, the inclined portion being formed in a peripheral area of the main thickness portion, the inclined portion gradually decreasing in thickness from a portion in contact with the main thickness portion to an outermost periphery of the second excitation electrode, and
the main thickness portion has a thickness larger than a thickness of the first excitation electrode,
wherein the inclined portion has an inclination width as a width of the inclined portion,
the inclination width being formed to have a length of 0.5 times or more and three times or less a flexural wavelength that is a wavelength of a flexure vibration as an unnecessary vibration.