Ultrasonic motor

One common application of ultrasonic motors is in camera lenses where they are used to move lens elements as part of the auto-focus system.

Later designs by Sashida and researchers at Matsushita, ALPS, and Canon made use of traveling-wave vibration to obtain bi-directional motion, and found that this arrangement offered better efficiency and less contact interface wear.

More generally, there are two types of motors, contact and non-contact, the latter of which is rare and requires a working fluid to transmit the ultrasonic vibrations of the stator toward the rotor.

Numerous patents on ultrasonic motors have been filed by Canon, its chief lensmaking rival Nikon, and other industrial concerns since the early 1980s.

[6] The ultrasonic motor is now used in many consumer and office electronics requiring precision rotations over long periods of time.