A lens barrel includes an element displaced by application of voltage; an elastic body having a contact surface coming into contact with the element, a drive surface to produce a vibration wave by displacement of the element, and a plurality of grooves; a moving element come into contact with the drive surface and rotated by the vibration wave; an annular ring rotated by rotating of the moving element; and a lens moved in an optical axis direction by rotating of the annular ring; wherein the element mainly contains a material having potassium sodium niobate, potassium niobate, sodium niobate, or barium titanate, wherein a value of [(T/B)÷W] is in a range of 0.84 to 1.94, where T represents a depth of the groove, B represents a distance from a bottom part of the groove to the contact surface, and W represents a radial width of the elastic body.

A lens barrel includes an element displaced by application of voltage; an elastic body having a contact surface coming into contact with the element, a drive surface to produce a vibration wave by displacement of the element, and a plurality of grooves; a moving element come into contact with the drive surface and rotated by the vibration wave; an annular ring rotated by rotating of the moving element; and a lens moved in an optical axis direction by rotating of the annular ring; wherein the element mainly contains a material having potassium sodium niobate, potassium niobate, sodium niobate, or barium titanate, wherein a value of [(T/B)÷W] is in a range of 0.84 to 1.94, where T represents a depth of the groove, B represents a distance from a bottom part of the groove to the contact surface, and W represents a radial width of the elastic body.

A vibration wave motor, includes a vibrator including an electro-mechanical energy conversion element and an elastic body, and a contact body, wherein the elastic body includes a flat plate portion on which the electro-mechanical energy conversion element is fixed, and a protruding portion, wherein the protruding portion includes a contact portion, a side wall portion, and a coupling portion that is configured to couple the contact portion and the side wall portion, and wherein a predetermined inequality is satisfied, where a thickness of the side wall portion in a direction orthogonal to the pressure direction is t1, and a distance in the pressure direction from a second surface of the flat plate portion to the coupling portion is h1, the second surface of the flat plate portion facing a first surface of the flat plate portion on which the electro-mechanical energy conversion element is fixed.

A high-torque and high-precision ultrasonic motor with a self-protection function and an implementation mode of the high-torque and high-precision ultrasonic motor are provided. In the device, a gasket encloses an output shaft of an ultrasonic motor body. A harmonic reducer encloses a shell of the ultrasonic motor body. A motor shaft penetrates through the ultrasonic motor body. The end, close to the motor shaft, of the ultrasonic motor body is defined as a top end, and the bottom end of the motor shaft is sequentially enclosed with an encoder support and a high-precision encoder assembly. The gasket, the harmonic reducer, the encoder support and the high-precision encoder assembly are sequentially arranged from the ultrasonic motor body to the bottom end of the motor shaft. After the ultrasonic motor body decelerates and increases torque, the motor shaft outputs rotating speed and torque.

A vibration wave motor includes an annular oscillator, and an annular moving member provided so as to be in press contact with the oscillator. The oscillator includes an annular vibrating plate, and an annular piezoelectric element provided on a first surface of the vibrating plate. The vibrating plate is in contact with the moving member via a second surface of the vibrating plate, which is opposite the first surface. The piezoelectric element has a plurality of drive phase electrodes. When a driving region represents a region of the oscillator in which the drive phase electrodes are provided, and a non-driving region represents a remaining region of the oscillator, a contact area ratio S1 between the vibrating plate and the moving member in the non-driving region is less than a contact area ratio S2 between the vibrating plate and the moving member in the driving region.

A vibration wave motor includes an annular oscillator, and an annular moving member provided so as to be in press contact with the oscillator. The oscillator includes an annular vibrating plate, and an annular piezoelectric element provided on a first surface of the vibrating plate. The vibrating plate is in contact with the moving member via a second surface of the vibrating plate, which is opposite the first surface. The piezoelectric element has a plurality of drive phase electrodes. When a driving region represents a region of the oscillator in which the drive phase electrodes are provided, and a non-driving region represents a remaining region of the oscillator, a contact area ratio S1 between the vibrating plate and the moving member in the non-driving region is less than a contact area ratio S2 between the vibrating plate and the moving member in the driving region.

A composite motor having high-precision positioning, comprising: a housing (1), a rough positioning assembly, a hollow output shaft (2), a fine positioning assembly, a power switching apparatus and a controller (6). A stepper motor (3) in the rough positioning assembly is responsible for rough positioning of the composite motor, an annular travelling wave ultrasonic motor in the fine positioning assembly is responsible for tail end fine positioning of the composite motor, and the controller (6) implements power output switching between the annular travelling wave ultrasonic motor and the stepper motor (3). The composite motor effectively solves the problem that annular travelling wave ultrasonic motors which operate continuously for a long time have a short service life, and ensures high-precision positioning while also extending motor service life.

Provided are a barium titanate-based piezoelectric ceramics having satisfactory piezoelectric performance and a satisfactory mechanical quality factor (Q.sub.m), and a piezoelectric element using the same. Specifically provided are a piezoelectric ceramics, including: crystal particles; and a grain boundary between the crystal particles, in which the crystal particles each include barium titanate having a perovskite-type structure and manganese at 0.04% by mass or more and 0.20% by mass or less in terms of a metal with respect to the barium titanate, and the grain boundary includes at least one compound selected from the group consisting of Ba.sub.4Ti.sub.12O.sub.27 and Ba.sub.6Ti.sub.17O.sub.40, and a piezoelectric element using the same.

One aspect of the invention relates to a vibration type drive device including: a mechanical energy application element; a resilient member provided with the mechanical energy application element; a driven member subjected to a relative displacement with respect to the resilient member due to a vibration excited by the resilient member, wherein the resilient member includes a conductive material, and does not constitute an electric closed loop.

The present invention relates to a vibration-type driving apparatus including a vibrator including an electro-mechanical transducer; a driven body disposed in pressure-contact with the vibrator; a supporting portion extending from the vibrator; a base to which the vibrator is fixed with the supporting portion interposed therebetween; a vibration absorber disposed between the supporting portion and the base; and a compressive-force adjusting device capable of adjusting a compressive force to be applied to the vibration absorber between the supporting portion and the base.