Patent ID: 7733587

Claim:
A driving device comprising: a movable portion; a driving portion for driving said movable portion in a predetermined direction; a cabinet for covering said movable portion and said driving portion; and a position detecting device for detecting a current position of said movable portion, wherein said driving portion comprises: an electro-mechanical transducer having a pair of end portions opposite to each other in an expansion/contraction direction, said electro-mechanical transducer expanding or contracting in the predetermined direction; and a vibration friction portion mounted to one of the end portions of said electro-mechanical transducer, wherein said movable portion comprises a moving portion frictionally coupled to said vibration friction portion so as to move in a vibration direction of said vibration friction portion, whereby said driving portion drives said moving portion due to vibrations in the expansion/contraction direction of said electro-mechanical transducer, wherein said position detecting device includes an optical position detecting element and a position information portion which are disposed so as to be opposed to each other, one of said optical position detecting element and said position information portion being mounted on said movable portion, the other of said optical position detecting element and said position information portion being mounted on an internal wall of said cabinet, wherein said position information portion has a binary pattern where a high light efficient portion and a low light efficient portion are alternately repeated when said movable portion moves in the predetermined direction, wherein said position detecting device comprises: a loose position detecting portion for detecting a loose position of said movable portion by counting a pulse signal obtained by said optical position detecting element, said loose position detecting portion producing loose position detected information indicative of the detected loose position; a close position detecting portion for detecting a close position of said movable portion by counting pulse number of driving pulses which are applied to said electromechanical transducer from a point where the loose position detection is carried out by said loose position detecting portion, said close position detecting portion producing close position detected information indicative of the detected close position; and a combining arrangement for combining the loose position detected information with said close position detected information to calculate the current position of said movable portion.