Piezoelectric actuator, liquid transporting apparatus, and method for manufacturing piezoelectric actuator

A liquid transporting apparatus comprising:

• a liquid transporting head having a cavity unit in which a plurality of pressure chambers are formed, and a piezoelectric actuator which is joined to the cavity plate to selectively transport liquid in the pressure chambers, and which includes a first piezoelectric layer, a second piezoelectric layer stacked on the first piezoelectric layer, a first electrode arranged on the first piezoelectric layer on a side opposite to the second piezoelectric layer, a second electrode arranged between the first piezoelectric layer and the second piezoelectric layer, and a third electrode arranged on the second piezoelectric layer on a side opposite to the first piezoelectric layer;
• and
• a voltage applying mechanism which applies a voltage to the piezoelectric actuator, and which applies a first electric potential to the first electrode, a second electric potential different from the first electric potential to the second electrode, and the first electric potential and the second electric potential selectively to the third electrode,
• wherein a portion, of the third electrode, faces the second electrode, and another portion, of the third electrode, not facing the second electrode faces the first electrode,
• the first electrode does not face at least a portion of the second electrode, and
• a portion, of the second piezoelectric layer, sandwiched between the second electrode and the third electrode is polarized in a first direction in a thickness direction of the second piezoelectric layer, and a portion of the first piezoelectric layer and a portion of the second piezoelectric layer, which are sandwiched between the first electrode and the third electrode and between which the second electrode is not arranged, are polarized in a direction opposite to the first direction.

A method for manufacturing piezoelectric actuator comprising:

• forming a piezoelectric stacked body having:
• a first piezoelectric layer;
• a second piezoelectric layer stacked on the first piezoelectric layer;
• a first electrode arranged on the first piezoelectric layer on a side opposite to the second piezoelectric layer;
• a second electrode arranged between the first piezoelectric layer and the second piezoelectric layer;
• and a third electrode arranged on the second piezoelectric layer on a side opposite to the first piezoelectric layer;
• the third electrode having a portion facing the second electrode, the third electrode having another portion not facing the second electrode and facing the first electrode, and the first electrode not facing at least a portion of the second electrode;
• and
• polarizing a portion, of the second piezoelectric layer, sandwiched between the second electrode and the third electrode in a first direction in a thickness direction of the second piezoelectric layer, and a portion of the first piezoelectric layer and a portion of the second piezoelectric layer, which are sandwiched between the first electrode and the third electrode and between which the second electrode is not arranged, in a direction opposite to the first direction, by generating electric potential differences simultaneously between the first electrode and the third electrode and between the second electrode and the third electrode.