An ultrasonic actuator with increased radiating surface is presented. The increased radiating surface is provided by a plurality of piezoelectric stacks that are each compressed by action of a respective bolt against a common backing structure of the actuator. According to one aspect, each of the stacks includes a plurality of stacked piezoelectric rings with the respective bolt arranged through the central opening of the rings. According to another aspect, one or both of the backing structure and the horn of the actuator include tuning grooves and/or tuning slots to produce amplitude uniformity of displacement through the actuator. According to another aspect, the radiating surface has a symmetrical shape about an axial direction of the actuator with a lateral dimension that is in a range between one quarter and one half of the wavelength of operation of the actuator.

A medical, particularly a dental or dental surgical, ultrasonic treatment device for generating ultrasonic vibrations and transmitting the ultrasonic vibration to a tool, which can be connected to the ultrasonic treatment device, the medical ultrasonic treatment device having: an ultrasonic vibration generator with a plurality of piezoelectric elements to which an electric voltage can be applied, and a circuit board to supply the plurality of piezoelectric elements with the electric voltage. Furthermore, a method for manufacturing a corresponding medical ultrasonic treatment device is described.

A piezoelectric transformer comprises at least a laminate of a first member, a first piezoelectric element, a second piezoelectric element and a second member sequentially stacked one on the other in the above-listed order and a pressurizing mechanism for squeezing the first member and the second member together in the stacking direction. The ratio of the electromechanical coupling coefficient k.sub.33 relative to the electromechanical coupling coefficient k.sub.31 (k.sub.33/k.sub.31) of the first piezoelectric element and the second piezoelectric element is not less than 2.0.

An ultrasonic transducer, including a piezoelectric element with physical characteristics of radial resonant frequencies and thickness resonant frequencies, and with an upper surface and a lower surface opposite to each other through the piezoelectric element and a lateral surface connecting the upper surface and the lower surface, and an acoustic matching layer set on the upper surface of the piezoelectric element and having a first resonant matching part and a second resonant matching part, wherein a thickness of the first resonant matching part in a direction perpendicular to the upper surface is greater than a thickness of the second resonant matching part in the direction, and the thickness of the first resonant matching part matches one radial resonant frequency of the piezoelectric element and the thickness of the second resonant matching part matches another radial resonant frequency or one of the thickness resonant frequency of the piezoelectric element.

An apparatus for converting wave energy into electrical energy including a float element excited at a defined frequency by the waves. A power extraction system collaborates with the float element to convert mechanical energy into electrical energy, the mechanical energy coming from the movement of the float element excited by the waves. The power extraction system takes the form of a frequency amplifier made up of at least two piezoelectric motors each composed of at least one piezoelectric post excited at a frequency higher than that of the float, and a member for activating said piezoelectric motors acting on the piezoelectric motors so as to squash said piezoelectric posts. Each piezoelectric motor has a mechanical amplification device connected to rollers and includes a) jaws able to apply mechanical stress to the posts, b) a lever acting on the jaws with a proximal end connected to said jaws and a distal end connected to a roller in contact with the member so as to activate said piezoelectric motor.

A PZT transducer-horn integrated ultrasonic driving structure consists of a nut, a bolt, a left PZT circular stack, a flange, a right PZT truncated stack and a horn. The horn, the right PZT truncated stack, the flange and the left PZT circular stack are arranged in sequence and connected via the bolt and then fastened via the nut; the right PZT transducer is a truncated cone-shaped stack formed by PZT circular plates; and the right PZT transducer and the horn are integrated to form the ultrasonic driving structure. Considering the dimension of PZT on two sides of the flange and the horn meet the requirements for ultrasonic vibration node and antinode, the dimension of round contour of the circular PZT stack and flange is reduced to increase the thickness of the truncated PZT stack and flange. With the integrated structure, the effect of reducing the contour dimension of the ultrasonic driving surgical device can be obtained, and the outer diameter is reduced to the range of 8-10 mm as compared with the range of 12-15 mm in the prior art, thereby further meeting the application requirements.

The present invention is related to a stretchable tubular device (1) comprising at least one layer (Lx) of a stretchable polymer, a power supply (2) and a set of electrodes (3a, 3b) connected to said power supply (2). The power supply can supply at least a first level of voltage (V1) to the electrodes so as to modify the natural force (F0) of the stretchable layers to a modified force (F1). The present invention also covers a process for manufacturing such a tubular device and its use as a medical implant.

A method of fabricating an ultrasonic medical device is presented. The method includes machining a surgical tool from a flat metal stock, contacting a face of a first transducer with a first face of the surgical tool, and contacting a face of a second transducer with an opposing face of the surgical tool opposite the first transducer. The first and second transducers are configured to operate in a D31 mode with respect to the longitudinal portion of the surgical tool. Upon activation, the first transducer and the second transducer are configured to induce a standing wave in the surgical tool and the induced standing wave comprises a node at a node location in the surgical tool and an antinode at an antinode location in the surgical tool.

To reduce the driving loss in the diaphragm, and to ensure a good sound output in the wide bandwidth. It includes a circular coil bobbin at least partly disposed between a yoke and a magnet, a coil wound around the coil bobbin, the coil being configured to be moved with the coil bobbin where a driving current is supplied to the coil, a piezoelectric element having one end coupled to one end of the coil bobbin in a movement direction, the piezoelectric element being configured to be expanded and contracted and moved in a direction same as the movement direction where an electric current is supplied to the piezoelectric element, and a diaphragm having an inner circumference part coupled to another end of the piezoelectric element, and a coupled part of the diaphragm to the piezoelectric element and a coupled part of the piezoelectric element to the coil bobbin are positioned on a straight line in the movement direction.

A measurement transducer for simultaneously measuring a force that can be both dynamic and static includes at least one piezoelectric transducer element having element surfaces on which the force generates electrical polarization charges proportional to a magnitude of the force. The measurement transducer includes a resonator element which can be excited to at least one resonance frequency and undergoes a transverse expansion from the action of the force in a transverse direction to the force. The magnitude of the transverse expansion is proportional to the magnitude of the force and causes in the resonance frequency a change that is a function of the force.