Patent ID: 7193351

Claim:
A driving device comprising: an electromechanical transducer, which expands or contracts under voltage from a driving pulse generator; a rod, one end of which is fixed to one end of the electromechanical transducer, in expanding or contracting direction; and a moving unit, which is frictionally coupled to the rod, and which is driven along the rod when the rod vibrates with expanding and contracting of the electromechanical transducer; wherein the driving pulse generator cyclically applies 4 voltage values, which are stepwise and sequentially increased, to the electromechanical transducer, such that sawtooth-like vibration generated thereby on the rod drives the moving unit in one direction along the rod, and cyclically applies 4 voltage values, which are stepwise and sequentially decreased, to the electromechanical transducer, such that sawtooth-like vibration generated thereby on the rod drives the moving unit in opposite direction along the rod; the 4 voltage values which are stepwise and sequentially increased and the 4 voltage values which are stepwise and sequentially decreased are generated by controlling of turning “on” or “off” of a plurality of switching elements, which are disposed in a circuit arrangement, wherein the electromechanical transducer, and 1st and 2nd capacitors are disposed between a positive power supply and a negative power supply; the turning “on” or “off” of the switching elements are controlled, such that: when the moving unit is driven in the one direction by one voltage value of the 4 voltage values which are stepwise and sequentially increased, the 1st capacitor is to be a parallel positional relationship with the electromechanical transducer and the 2nd capacitor which are serially connected, relative to the current flow, and such that: when the moving unit is driven in the opposite direction by one voltage value of the 4 voltage values which are stepwise and sequentially decreased, the 2nd capacitor is to be a parallel positional relationship with the electromechanical transducer and the 1st capacitor which are serially connected, relative to the current flow; another switching element is arranged in serial to the 1st capacitor, which is opened when the 1st capacitor has a parallel positional relationship with the serially connected electromechanical transducer and 2nd capacitor; and still another switching element is arranged in serial to the 2nd capacitor, which is opened when the 2nd capacitor C 2 has a parallel positional relationship with the serially connected electromechanical transducer and 1st capacitor.