Abstract: A piezoelectric device 1 for an injector, built into an injector and generating driving force of the injector, wherein a relation d(0.1 Ec)/d(1.2 Ec)≧0.50 is established between an apparent piezoelectric constant d(1.2 Ec) calculated from static elongation when an electric field of 1.2 Ec is applied to the piezoelectric device in the same direction as a polarizing direction while a preset load of 500 N is applied to the piezoelectric device, and an apparent piezoelectric constant d(0.1 Ec) calculated from static elongation when an electric field of 0.1 Ec is applied to the piezoelectric device in the same direction as the polarizing direction. The piezoelectric device so fabricated has high durability and can be used for a long time.

Abstract: A stacked piezoelectric device and a method of fabrication thereof includes a piezoelectric stack having a first side electrode and a second side electrode, piezoelectric layers and internal electrode layers. The piezoelectric layers and internal electrode layers have substantially the same area. The internal electrode layers have ends thereof exposed to one side of the stack. The first side electrode includes first insulative portions formed at the ends of alternate ones of the internal electrode layers and a first conductive portion formed over the first insulative portions. The second side electrode is similarly configured to form insulative portions at the other ends. The first and second insulative portions are formed of an insulative resin, while the first and second conductive portions are formed of a conductive resin. The first and second conductive portions are also formed to directly cover the ends of the internal electrode layers.

Abstract: A stacked piezoelectric device having high durability and a method of fabrication thereof facilitating easy control of the process of fabrication, comprising a piezoelectric stack (10) having a first side electrode (11) and a second side electrode (12), piezoelectric layers (131, 132) and internal electrode layers (141, 142) having substantially the same area, internal electrode layers (141, 142) having ends thereof exposed to the side (101) of the stack (10), the first side electrode (11) including first insulative portions (111) formed at the ends of alternate ones of the internal electrode layers (141) and a first conductive portion (121) formed over the first insulative portions (111), a second side electrode (12) being similarly configured to form insulative portions (112) at the other ends, the first and second insulative portions (111, 112) being formed of an insulative resin, while the first and second conductive portions (112, 122) being formed of a conductive resin.

Abstract: A piezoelectric device 1 for an injector, built into an injector and generating driving force of the injector, wherein a relation d(0.1 Ec)/d(1.2 Ec)≧0.50 is established between an apparent piezoelectric constant d(1.2 Ec) calculated from static elongation when an electric field of 1.2 Ec is applied to the piezoelectric device in the same direction as a polarizing direction while a preset load of 500 N is applied to the piezoelectric device, and an apparent piezoelectric constant d(0.1 Ec) calculated from static elongation when an electric field of 0.1 Ec is applied to the piezoelectric device in the same direction as the polarizing direction. The piezoelectric device so fabricated has high durability and can be used for a long time.