Patent ID: 8724240

Claim:
A piezoelectric actuator for driving a lens unit along an optical axis, comprising: a fixed member; a substantially rectangular movable member movably received in the fixed member, the movable member comprising a contacting portion positioned on a side surface of the movable member; a magnetic plate fixed on the fixed member; a magnet fixed on a same side surface of the movable member as the contacting portion and spaced from the contacting portion, the magnet being adjacent to the magnetic plate and aligned with the magnetic plate along a direction substantially perpendicular to the optical axis, the magnet and the magnetic plate providing a preload between the fixed member and the movable member; a piezoelectric member fixed on the fixed member and contacting on the contacting portion of the movable member, the piezoelectric be configured for driving the movable member to move along the optical axis; and a circuit board configured for providing voltages to the piezoelectric member.