Patent ID: 7926369

Claim:
An actuator comprising: a movable mass portion; and a pair of drive mechanisms for driving the movable mass portion, each of the pair of drive mechanisms including: (i) a drive mass portion, (ii) a support portion for supporting the drive mass portion, (iii) a first elastic connecting portion interconnecting the drive mass portion and the support portion so as to allow the drive mass portion to be pivoted about a pivotal axis with respect to the support portion, and (iv) a second elastic connecting portion interconnecting the drive mass portion and the movable mass portion so as to allow the movable mass portion to be pivoted about the pivotal axis with respect to the drive mass portion, the first elastic connecting portion including: (a) a pair of bending bars opposed to each other with the pivotal axis of the drive mass portion interposed therebetween, each of the pair of bending bars having a first connecting portion connected to the drive mass portion and a second connecting portion connected to the support portion, and (b) a pair of piezoelectric elements joined respectively onto the pair of bending bars so as to bend the pair of bending bars in opposite directions to cause pivotal movement to the drive mass portion, the pivotal movement of the drive mass portion causing torsional deformation to the second elastic connecting portion so as to pivot the movable mass portion thereby providing a two-degree-of-freedom vibration system wherein each of the drive mass portion and the movable mass portion is in the form of a quadrangular in a plan view thereof and has a pair of sides which are arranged parallel to the pivotal axis and symmetrically with the pivotal axis interposed therebetween, and wherein the first connecting portion of each of the bending bars is connected to the drive mass portion at a position between the pivotal axis and one of the sides of the drive mass portion.