Patent ID: 7456546
Filing Date: 2008-11-25
Classification: H02N

Abstract:
1. A drive unit comprising: an electromechanical transducer capable of expanding/contracting by drive signal application, a supporting member that is connected to said electromechanical transducer and displaced together with said electromechanical transducer, a movable object that is slidably supported on said supporting member and moves along said supporting member owing to a vibration of said supporting member by virtue of the expansion/contraction of said electromechanical transducer, a restricting member that restricts a movable range of said movable object, and a drive circuit that applies to said electromechanical transducer a first wave drive signal for vibrating said supporting member so that a difference occurs between the expansion and contraction of said supporting member when said movable object is moved to a position where said movable object makes contact with said restricting member, and applies to said electromechanical transducer a second wave drive signal for vibrating said supporting member so that said movable object is moved in a direction of movement away from said restricting member to the extent that said movable object is not detached from said restricting member after said movable object makes contact with said restricting member, and then stops the applications of said drive signals.