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AssigneeNGK Insulators, Ltd.
InventorsRitsu Tanaka, Hirofumi Yamaguchi, Yukinobu Yura, Shuichi Ozawa
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A monomorph type piezoelectric/electrostrictive device includes a piezoelectric/electrostrictive body, which is composed of a non-lead based piezoelectric/electrostrictive crystalline body containing at least Nb, Ta, and one or more types of alkali metal element, which has a cubic crystal structure at a temperature higher than the phase transition point and at least any one of tetragonal and orthorhombic crystal structures at a temperature lower than the phase transition point, and which is curved to a large extent by a polarization treatment to take on a curved shape at a temperature lower than the phase transition point without application of a voltage after the polarization treatment. In the polarization treatment, an electric field is increased at a speed of from 0.1 (kV/mm)/sec or more to 5 (kV/mm)/sec or less, with applying the maximum electric field of from 2 kV/mm or more to 1.0 kV/mm or less.
A monomorph type piezoelectric/electrostrictive device comprising a non-lead based piezoelectric/electrostrictive crystalline body containing at least Nb, Ta, and one or more types of alkali metal element, wherein the piezoelectric/electrostrictive crystalline body has a cubic crystal structure at a temperature higher than a phase transition point and at least any one of tetragonal and orthorhombic crystal structures at a temperature lower than the phase transition point, and wherein the piezoelectric/electrostrictive crystalline body shows a curved shape having a degree of curving larger than that before a polarization treatment at a room temperature lower than the phase transition point, when the piezoelectric/electrostrictive crystalline body is subjected to the polarization treatment.
A method for manufacturing a monomorph type piezoelectric/electrostrictive device comprising a non-lead based piezoelectric/electrostrictive crystalline body containing at least Nb, Ta, and one or more types of alkali metal element, wherein the piezoelectric/electrostrictive crystalline body has a cubic crystal structure at a temperature higher than a phase transition point and at least any one of tetragonal and orthorhombic crystal structures at a temperature lower than the phase transition point, and wherein the piezoelectric/electrostrictive crystalline body shows a curved shape having a degree of curving larger than that before a polarization treatment at a room temperature lower than the phase transition point, when the piezoelectric/electrostrictive crystalline body is subjected to the polarization treatment, which includes the step of
Dependencies are inferred from the claim text.