Patent ID: 6943481

Claim:
A vibration member comprising: an elastic member; and a circular electro-mechanical energy conversion element that is fixed to said elastic member and has an electrode film formed on at least one side; wherein said electro-mechanical energy conversion element has at least a first electrode group in which a plurality of electrodes are provided on a first circumference, the first electrode group being made up of a first portion of electrodes and a distinct second portion of electrodes, and a second electrode group in which a plurality of electrodes are provided on a second circumference different than the first circumference, the second electrode group being made up of a first portion of electrodes and a distinct second portion of electrodes, wherein a first standing wave is generated on a surface of said vibration member by applying a first alternating signal to the first portion of electrodes of the first electrode group and to the first portion of electrodes of the second electrode group, and a second standing wave is generated on the surface of said vibration member by applying a second alternating signal to the second portion of electrodes of the first electrode group and to the second portion of electrodes of the second electrode group, and wherein a traveling wave is excited on said surface of said vibration member by compositing said first standing wave and said second standing wave.