Piezoelectric actuator

A piezoelectric actuator comprising:

• a plate including:
• first and second surfaces that are separated from each other by a predetermined distance in a thickness direction and that extend in a predetermined planar direction substantially perpendicular to the thickness direction;
• and
• an operation portion having:
• a first portion;
• and
• a pair of second portions disposed symmetrically on either side of the first portion with respect to the planar direction;
• and
• at least one electrode located in each second portion, an active portion, defined in each second portion by the electrode, being located nearer to the first surface than the second surface in the thickness direction, at least the active portion in the plate being formed from piezoelectric material, the electrode generating an electric field for deforming the active portion in the planar direction, thereby bending each second portion in a direction from one to the other of the first surface and the second surface, and consequently bending the first portion in an opposite direction from the other to the one of the first surface and the second surface, thereby deforming the operation portion in the thickness direction.