Patent ID: 7504761

Claim:
A driving device comprising: an electromechanical conversion element enabled to expand and in response to input of an electrical signal, the electromechanical conversion element extending longitudinally between two opposite end portions; a stationary member; a weight member that is not supported by or otherwise fixed to the stationary member, the weight member being mounted to only one of the first and second opposite end portions of the electromechanical conversion element so as to transmit an expansion/contraction force produced by the electrical signal to the opposite end portion not mounting the weight member; and a frictional member that is frictionally-engaged with the electromechanical conversion element and that is mounted on the electromechanical conversion element so as to be movable along a longitudinal direction of the electromechanical conversion element in response to expansion/contraction of the electromechanical conversion element.