Electromechanical transducer

An electromechanical transducer comprising:

• a plurality of cells, each of which has a vibrating film including a first electrode and has a second electrode provided opposing the first electrode with a gap therebetween;
• driving and detecting means that includes first and second driving and detecting means for implementing at least one of a transmitting function which generates a potential difference between the first and the second electrodes to vibrate the vibrating film and a receiving function which detects a displacement of the vibrating film by a change in a capacitance between the first electrode and the second electrode;
• and
• switching means;
• wherein a first element is formed, in which at least two cells, among a plurality of the cells, having the first electrodes thereof electrically connected and further connected to the same first driving and detecting means constitute one group, and a second element is formed, in which at least two cells, among a plurality of the cells, having the second electrodes thereof electrically connected and further connected to the same second driving and detecting means constitutes one group, and a plurality of at least one of the first and the second elements is provided,
• at least one cell is different between the cells constituting the first element and the cells constituting the second element, and
• the switching means switches the driving and detecting means for implementing the function between the first driving and detecting means and the second driving and detecting means at the time of carrying out a transmitting and receiving operation.