Abstract: A composite structure of a backing material with enhanced conductivity for use in a transducer is presented. The composite structure includes a plurality of layers of backing material alternatingly arranged with a plurality of thermal conductive elements, wherein the plurality of thermal conductive elements are configured to transfer heat from a center of the transducer to a plurality of points on the composite structure of backing material.

Abstract: The present invention relates to a continuous filtration device in a liquid path, characterized in that it comprises, in combination: a modular ultrasonic treatment unit (12) which is in the form of a tubular metal body (11) with a cylindrical internal surface (13) and of circular cross section, open at both its feed end (10) and its discharge end (15), the external surface of the said tubular metal body having, in the vicinity of the nodal zone, a collar (17) which is coaxial with the said tube and which projects radially, this collar being equipped at its periphery with an ultrasonic converter (19) which projects radially and whose frequency is equal to the vibration frequency of the said collar (17) and to the longitudinal vibration frequency of the said tubular metal body (11), and a filtering cylindrical element (14) having a minimum filtration area of about 50 cm2 and preferably about 80 cm2 with a mesh opening less than about 20 ?m, which is arranged inside the tubular metal body (11) and coaxially

Abstract: A frequency-tunable resonator comprises a basic element having at least one piezoelectric layer and at least one semiconducting layer. The electrodes, formed on main surface situated opposite one another of the basic element, are loaded with an external voltage, whereby the resonant frequency of the basic element or of the resonator can be in dependence on the voltage.

Abstract: An acoustic transducer design having a slotted oval-shaped shell and active transducer elements located on the inner surface of the shell is disclosed. The design provides a high power, ultra-low frequency oval projector having a number of applications, including underwater seismic prospecting and fish mitigation.

Abstract: Embodiments of an acoustically-coupled transformer have a first stacked bulk acoustic resonator (SBAR) and a second SBAR. Each of the SBARs has a lower film bulk acoustic resonator (FBAR) and an upper FBAR, and an acoustic decoupler between the FBARs. The upper FBAR is stacked atop the lower FBAR. Each FBAR has opposed planar electrodes and a piezoelectric element between the electrodes. The piezoelectric element is characterized by a c-axis. The c-axes of the piezoelectric elements of the lower FBARs are opposite in direction, and the c-axes of the piezoelectric elements of the upper FBARs are opposite in direction. The transformer additionally has a first electrical circuit connecting the lower FBAR of the first SBAR to the lower FBAR of the second SBAR, and a second electrical circuit connecting the upper FBAR of the first SBAR to the upper FBARs of the second SBAR.

Abstract: A gas sensor (10) including a measurement chamber (28) into which a gas GS is flown and a detection element main body (40) facing the measurement chamber (28). The detection element main body (40) includes an element case 42, and a protective film (48) is adhered to a bottom surface thereof. An acoustic matching plate (50) and a piezoelectric element (51) of a substantially columnar shape and a tube body (52) provided in a position surrounding the acoustic matching plate 50 and the piezoelectric element 51 are housed in the element case (42). A filler is then introduced into the element case (42), whereby the acoustic matching plate (50), the piezoelectric element (51), and the tube body (52) are sealed by a filled layer (99).

Abstract: An acoustic wave sensor having a piezoelectric substrate shaped to generate lateral electric fields. The sensor has a pair of electrodes deposited upon a reference surface of the substrate. A sensing surface that is opposite from the reference surface is adapted to be immersed in an environment, such as a gas or a liquid.

Abstract: An acoustic sensor for use in a downhole measurement tool is provided. The acoustic sensor includes a piezoelectric transducer and a matching layer assembly having at least one matching layer and a barrier layer. In various exemplary embodiments, the at least one matching layer includes first and second matching layers formed from a glass ceramic work piece and the barrier layer includes corrugated titanium. Exemplary embodiments of this invention may advantageously withstand the extreme temperatures, pressures, and mechanical shocks frequent in downhole environments and thus may exhibit improved reliability. A method for fabricating an acoustic sensor is also provided.

Abstract: Provided is a multiplexer for a biometric apparatus. The multiplexer includes a plurality of first conductors coupled to the first ends of piezo ceramic elements in corresponding rows and a plurality of first switches each of which is coupled to a respective one of the first conductors and a plurality of second conductors coupled to the second ends of piezo ceramic elements in corresponding columns. The multiplexer also includes a plurality of second switches each of which is coupled to a respective one of the second conductors. The first conductors are approximately orthogonal to the second conductors, and the first switches are controlled to couple a signal output from an output port of the signal generator to a particular piezo ceramic element of the at least twenty five thousand piezo ceramic elements. The second switches are controlled to couple a signal associated with the particular piezo ceramic element of the at least twenty five thousand piezo ceramic elements to an input port of the processor.

Abstract: An ultrasonic transducer according to the present invention includes: a piezoelectric body 4 to set up ultrasonic vibrations; an acoustic matching layer 3 made of a material with a density of 50 kg/m3 to 1,000 kg/m3 and an acoustic impedance of 2.5×103 kg/m2/s to 1.0×106 kg/m2/s; a lower acoustic matching layer 9 provided between the piezoelectric body 4 and the acoustic matching layer 3; and a structure supporting member 6 that supports the lower acoustic matching layer 9 and the piezoelectric body 4 thereon and shields the piezoelectric body 4 from a fluid that propagates the ultrasonic vibrations. The ultrasonic transducer includes a protective portion, which contacts with at least a portion of a side surface of the acoustic matching layer 4. This protective portion is defined by a portion of the lower acoustic matching layer 9 and forms an integral part of the lower acoustic matching layer 9.

Abstract: An acoustic driver assembly for use with a spherical cavitation chamber is provided. The acoustic driver assembly includes at least one transducer, a head mass and a tail mass, coupled together with a centrally located threaded means (e.g., all thread, bolt, etc.). The driver assembly is either attached to the exterior surface of the spherical cavitation chamber with the same threaded means, a different threaded means, or a more permanent coupling means such as brazing, diffusion bonding or epoxy. In at least one embodiment, the transducer is comprised of a pair of piezo-electric transducers, preferably with the adjacent surfaces of the piezo-electric transducers having the same polarity. The surface of the head mass that is adjacent to the external surface of the chamber has a spherical curvature greater than the spherical curvature of the external surface of the chamber, thus providing a ring of contact between the acoustic driver and the cavitation chamber.

Abstract: In an ultrasonic transducer, the transducer elements are electrically connected to the pulsers via throughholes in an acoustic backing layer. Electrically conductive material is deposited on the front face of the acoustic backing layer and later diced to form conductive pads, and on the walls of the throughholes or vias to form conductive traces having exposed ends that will be connected later to a printed circuit. The holes in the acoustic backing layer are then filled with acoustic attenuative material. The signal electrodes on the rear faces of the transducer elements are electrically connected to the printed circuit via the conductive pads and the conductive traces of the acoustic backing layer. A common ground connection is disposed between the front faces of the transducer elements and the acoustic impedance matching layer, which ground connection exits the transducer pallet from the side.

Abstract: The present invention provides a composite piezoelectric transducer having a piezoelectric ceramic, an organic polymer, and an electrode group formed only on surfaces of the piezoelectric ceramic. The groove is formed, having a depth 50% to 90% of the thickness of the piezoelectric ceramic. A ratio, between a width of a non-diced area formed by forming the groove on the piezoelectric ceramic and the depth of the groove is 0.2 to 0.7. An organic polymer is filled in the groove formed in the piezoelectric ceramic in a state including bubbles. The electrode group comprises a first electrode and a second electrode, the first electrode being formed on a first surface of the piezoelectric ceramic, and the second electrode being formed on a second surface of the piezoelectric ceramic, a side surface thereof, or on the second surface, the side surface and the first surface, the second surface being opposite to the first surface in the direction of the thickness of the piezoelectric ceramic.

Abstract: An acoustic driver assembly for use with a spherical cavitation chamber is provided. The acoustic driver assembly includes at least one transducer, a head mass and a tail mass, coupled together with a centrally located threaded means (e.g., all thread, bolt, etc.). The head mass of the driver assembly is permanently attached to the exterior surface of the spherical cavitation chamber via brazing or diffusion bonding. In at least one embodiment, the transducer is comprised of a pair of piezo-electric transducers, preferably with the adjacent surfaces of the piezo-electric transducers having the same polarity. The surface of the head mass that is adjacent to the external surface of the chamber has a spherical curvature equivalent to the spherical curvature of the external surface of the chamber, thus providing maximum coupling efficiency between the acoustic driver and the cavitation chamber.

Abstract: A flat multilayered component for use as an actuator or a sensor, is described. The flat multilayered component contains a layer of electrically activatable material, a passive middle layer disposed adjacent the layer of electrically activatable material, and a further passive material layer disposed adjacent the passive middle layer. The passive middle layer has a higher coefficient of linear thermal expansion than both of the layer of electrically activatable material and the further passive middle layer.

Abstract: An ultrasonic apparatus comprising a hand piece (1) within a handle region (2), a connection tube (3) for connecting to a supply tube, wherein rock salt solution and medical healing agents such as heparin, antibioticts and the like are fed through the feed channel (5) to the sonotrode (7) or ultrasonic treatment head. The ultrasound energy is fed to the hand piece (1) through the connection line to the ultrasonic generator (4) in a conventional way.

Abstract: A method for manufacturing a multi-layer acoustic transducer with reduced total electrical impedance. The method is based on the bonding of two piezoelectric ceramic layers with confronting metallized surfaces to a thin electrical conductor, then electrically connecting the top and bottom surfaces to form a wrap-around electrode while a center conductor forms a second electrode. The total electrical impedance of a two-layer ceramic stack comprised of piezoelectric layers connected in this manner is one-fourth that of a solid ceramic element of the same size. This provides for better matching of the acoustic stack impedance to that of the electrical cable, increased penetration depth for imaging within the body, and improved acoustic element sensitivity.

Abstract: A piezoelectric transducer comprises a piezoelectric component, an acoustic member attached to one of the surfaces of the piezoelectric component and a dampening material of low elastic modulus attached to one or both surfaces of the piezoelectric transducer. The piezoelectric component may comprise either an unimorph or a bimorph structure including a piezoceramic wafer made of lead zirconate titanate and a layer of dampening material sandwiched between the piezoelectric component and the acoustic member. The acoustic member comprises a surrounding wall portion and an end portion which form an acoustic chamber when the member is mounted on a surface of the piezoelectrie component. The end portion has an orifice to form a passageway from the chamber through the end portion to the outside of the member.

Abstract: The band-pass filter has a stacked pair of film bulk acoustic resonators (FBARs) and an acoustic decoupler between the FBARs. Each of the FBARs has opposed planar electrodes and a layer of piezoelectric material between the electrodes. The acoustic decoupler has a single layer of acoustic decoupling material having a nominal thickness equal to an odd integral multiple of one quarter of the wavelength in the acoustic decoupling material of an acoustic wave having a frequency equal to the center frequency. The acoustic decoupling material comprises plastic. The acoustic decoupler controls the coupling of acoustic energy between the FBARs. Specifically, the acoustic decoupler couples less acoustic energy between the FBARs than would be coupled by direct contact between the FBARs. The reduced acoustic coupling gives the band-pass filter desirable in-band and out-of-band properties.

Abstract: A transducer assembly for receiving a stimulating signal and producing ultrasound therefrom at one or more frequencies, over an ultrabroad bandwidth at each frequency, includes a front mass disposed about a central axis, and a back mass disposed about the central axis, laterally offset from the front mass. The transducer assembly also includes one or more resonators disposed about the central axis and between the front mass and the back mass, including at least one electrical contact for receiving the stimulating signal. The back mass consists of a low-density material, such as aluminum, aluminum alloy, magnesium, or magnesium alloy, or any of various low-density materials known in the art. In general, the back mass is characterized by a density of less than 6.0 g/cc. In one embodiment, the front mass and the back mass are made from different materials, and the front mass includes a deviation from symmetrical symmetry.

Abstract: An electromechanical transducer formed by an electrical and mechanical combination of a piezoelectric device and a magnetostrictive device. The two devices are electrically coupled so that their capacitive and inductive reactances approach a balance to provide an essentially resistive combined input at a selected frequency. Efficiency of circuits driving the transducer is improved. The devices are mechanically coupled so that the mechanical outputs add or reinforce each other. Two transducer pairs may be used in a two frequency telemetry system with each pair tuned to one of the frequencies for optimal reactance balancing and transduction efficiency.

Abstract: An acoustic sensor for use in a downhole measurement tool is provided. The acoustic sensor includes a piezoelectric transducer and a backing layer having at least one powder material disposed in an elastomeric matrix material. In various exemplary embodiments, the backing layer includes first and second tungsten powders disposed in a fluoroelastomer matrix material. Exemplary embodiments of this invention may advantageously withstand the extreme temperatures, pressures, and mechanical shocks frequent in downhole environments and thus may exhibit improved reliability. A method for fabricating an acoustic sensor is also provided.

Abstract: Materials having different compositions are arranged to prepare a molded form in which the sound velocity characteristic is varied from high frequency to low frequency from the center toward the periphery. An ultrasonic wave-radiating face of the molded form and the back face of the ultrasonic wave-radiating face are arranged in parallel to each other to prepare a transducer in which the center region can transmit/receive high-frequency ultrasonic waves and the periphery region can transmit/receive low-frequency ultrasonic waves.

Abstract: Inner individual electrodes are formed at intervals on a piezoelectric ceramic layer so as to correspond in a one-to-one relationship with ink channels, and an inner common electrode are formed on another piezoelectric ceramic layer. The required number of piezoelectric ceramic layers with inner individual electrodes and with an inner common electrode are laminated alternately. An outer common electrode is connected to the inner common electrodes, and outer individual electrodes are connected to the respective inner individual electrodes. The capacitance between the outer common electrode and each of the outer individual electrodes is measured. A polarization electric field adjusted based on the measured value is applied between the common electrode and each of the outer individual electrodes to perform polarization.

Abstract: An acoustic matching layer 1 according to the present invention includes a first acoustic matching layer 2, which has a low density and a low sonic velocity, and a second acoustic matching layer 3, which has a higher density and a higher sonic velocity. The first acoustic matching layer 2, of which the acoustic impedance is matched to that of a medium into an ultrasonic wave is radiated, is provided closer to the medium, while the second acoustic matching layer 3 is provided closer to a piezoelectric layer, thereby increasing the sensitivity of an ultrasonic transducer.

Abstract: A matrix type piezoelectric/electrostrictive (P/E) actuator includes a plurality of piezoelectric/electrostrictive elements, each including a piezoelectric/electrostrictive body and at least one pair of electrodes formed on a ceramic substrate. The matrix type P/E actuator is activated by the displacement of the piezoelectric/electrostrictive bodies. The piezoelectric/electrostrictive elements are joined to the ceramic substrate as respective unified bodies, and are two-dimensionally arranged independently from each other. The piezoelectric/electrostrictive actuator provides a greater displacement with a lower voltage, a high responsive speed, and a greater generating force, as well as enhancing the mounting ability and the integration. A method for manufacturing such a matrix type P/E actuator is also disclosed.

Abstract: A multi-layer composite transducer array includes at least one pair of composite transducers with an electrical and mechanical isolation layer disposed therebetween. Each composite transducer is defined by a composite panel having a common electrode coupled to a first surface and electrode segments electrically isolated from one another and coupled to a second surface. Each pair of composite transducers is configured such that the electrode segments associated with the pair's composite transducers oppose and are aligned with one another. The isolation layer has dielectric material segments that are sized, shaped and aligned in correspondence with opposing and aligned ones of the electrode segments associated with the pair's transducers. Spaces formed in the isolation layer between the dielectric material segments are filled with a viscoelastic material.

Abstract: A composite piezoelectric transducer of the present invention includes a plurality of arranged piezoelectric elements, and dielectric portions positioned between the plurality of piezoelectric elements. In the composite piezoelectric transducer, an area of a cross-section perpendicular to an ultrasonic emitting direction in at least one piezoelectric element of the plurality of piezoelectric elements varies along the ultrasonic emitting direction.

Abstract: A composite transducer array comprises a piezoelectric polymer composite panel, a continuous electrode coupled to a first surface of the composite panel, and a plurality of electrically-isolated electrode segments coupled to a second surface of the composite panel. Each electrode segment is shaped as an angular segment of a circular ring. The electrode segments are arranged to define an array of concentric circular rings of electrode segments.

Abstract: The invention relates to an array of ultrasound transducers which each comprise a substrate (1), a membrane (2), a first electrode (4), a piezoelectric layer (5), and a second electrode (6), wherein the substrate (1) comprises at least one opening (3) which adjoins the membrane (2) at one side, while the piezoelectric layer (5) has a high piezoelectric coupling coefficient k and is textured. The invention further relates to an ultrasound transducer and to a method of manufacturing an array of ultrasound transducers.

Abstract: An acoustic matching layer according to the present invention includes a powder of a dry gel. The dry gel preferably has a density of 500 kg/m3 or less and an average pore diameter of 100 nm or less. By using the dry gel powder, a variation in the property of the acoustic matching layer can be reduced.

Abstract: The invention concerns an installation with piezoelectric element for transmitting or receiving ultrasonic waves in a structure, the electrodes (8) of said element (7) being connected, as the case may be, to a powering circuit producing energizing electric signals designed to enable it to transmit ultrasonic signals in said structure (6), or to a circuit receiving electric signals transmitted by said element under an energizing ultrasound received by it from said structure, said piezoelectric element (7) being integrated in the structure. The powering or receiving circuits of said piezoelectric elements (7) consist each of a magnetic induction loop (9) likewise comprised in the structure (6) and capable of receiving from an external circuit (10, 11) or respectively transmitting thereto, electromagnetic signals.

Abstract: An acoustic driver assembly for use with a spherical cavitation chamber is provided. The acoustic driver assembly includes at least one transducer, a head mass and a tail mass, coupled together with a centrally located threaded means (e.g., all thread, bolt, etc.). The driver assembly is permanently attached to the exterior surface of the spherical cavitation chamber via brazing or diffusion bonding. In at least one embodiment, the transducer is comprised of a pair of piezo-electric transducers, preferably with the adjacent surfaces of the piezo-electric transducers having the same polarity. The surface of the head mass that is adjacent to the external surface of the chamber has a spherical curvature equivalent to the spherical curvature of the external surface of the chamber, thus providing maximum coupling efficiency between the acoustic driver and the cavitation chamber. In at least one embodiment a void filling material is interposed between one or more pairs of adjacent surfaces of the driver assembly.

Abstract: An acoustic driver assembly for use with a spherical cavitation chamber is provided. The acoustic driver assembly includes at least one transducer, a head mass and a tail mass, coupled together with a centrally located threaded means (e.g., all thread, bolt, etc.). The driver assembly is either attached to the exterior surface of the spherical cavitation chamber with the same threaded means, a different threaded means, or a more permanent coupling means such as brazing, diffusion bonding or epoxy. In at least one embodiment, the transducer is comprised of a pair of piezo-electric transducers, preferably with the adjacent surfaces of the piezo-electric transducers having the same polarity. The surface of the head mass that is adjacent to the external surface of the chamber has a spherical curvature greater than the spherical curvature of the external surface of the chamber, thus providing a ring of contact between the acoustic driver and the cavitation chamber.

Abstract: A unidirectional acoustic probe including a high-performance interconnection network, and a method of manufacturing such a probe. The unidirectional acoustic probe includes linear piezoelectric transducers on the surface of a dielectric film. The dielectric film includes a connection device to electrically connect the piezoelectric transducers to a control device. The connection device includes primary connection pads, facing the piezoelectric transducers, secondary connection pads, offset with respect to the piezoelectric transducers, so that the transducers can be connected to the control device, and conducting tracks connecting the primary connection pads to the secondary connection pads. The conducting tracks are in a direction perpendicular to the direction defined by a major axis of the piezoelectric transducers.

Abstract: A composite piezoelectric transducer, whose piezoeletric element is a “ribbon wound” film of piezolectric material. As the film is excited, it expands and contracts, which results in expansion and contraction of the diameter of the entire ribbon winding. This is accompanied by expansion and contraction of the thickness of the ribbon winding, such that the sound radiating plate may be placed on the side of the winding.

Abstract: One aspect of the invention relates to a composite member for a resonator having an active piezoelectric element and a passive piezoelectric element. The active piezoelectric element causes the resonator to vibrate and detects the frequency of the vibration. The passive piezoelectric element changes the frequency of the vibration. Another aspect of the invention relates to a method for controlling a resonator with composite member having a substrate carrying a composite piezoelectric element. The composite piezoelectric element includes an actuator element, a sensor element and a passive element. The method comprises inducing a resonance within the composite member with the actuator element, detecting the resonance with the sensor element, and altering the resonance by altering the electromechanical coupling of the passive element. Additional aspects and benefits of the invention are also given.

Abstract: An apparatus examines the internal structure of an object disposed substantially in a medium such as air, which essentially totally reflects acoustic signals in the 1-200 MHz frequency range. The apparatus has an acoustic transducer that emits and receives acoustic signals in the 1-200 MHz frequency range and an acoustic coupler that acoustically couples the acoustic transducer to the object. The acoustic coupler has a first end adapted to couple to the acoustic transducer and a second end adapted to make contact with a section of a surface of the object. The acoustic coupler carries acoustic signals in the 1-200 MHz frequency range between the acoustic transducer and the contacted section of the surface of the object. In operation, the apparatus examines the internal structure of the object using reflection mode acoustic microscopy, wherein emitted and reflected signals are carried between the acoustic transducer and the object by acoustic coupler.

Abstract: A piezoelectric transducer comprises: a substrate having first and second substrate electrodes forming input and output terminals, and one or more piezoelectric elements for transmitting a supersonic wave to an object to be measured and receiving a reflected wave from the object. The piezoelectric elements are arranged on the substrate and have a first surface electrode connected to the first substrate electrode and a second surface electrode connected to the second substrate electrode via a conductive member. An acoustic matching layer is superposed on the piezoelectric elements for efficiently propagating the supersonic wave on the second surface electrode. The conductive member has a thickness not more than that of the acoustic matching layer and is embedded in the acoustic matching layer.

Abstract: A method is furnished for a treatment of septic wounds. A hand piece of a sonotrode is connected to a liquid storage. Access to a wound is furnished to the sonotrode. A liquid atomized by ultrasound is delivered to the wound through a sonotrode channel disposed in the sonotrode. Bacteria in the area of the wound are destroyed by the ultrasound emitted by the sonotrode. The method allows to remove a prosthesis not longer desired from a patient. The area left open by the removed prosthesis and/or a bone is filled with a liquid. The sonotrode is then entered into the liquid for propagating ultrasound through the liquid and thereby destroying bacteria present in the liquid.

Abstract: A component operating with bulk acoustic waves has two Bulk Acoustic Wave (BAW) resonators that are stacked and are acoustically coupled to one another, with a first resonator being connected to an asymmetric port, and a second resonator being connected to a symmetrical port. The acoustic coupling is provided by a partially permeable coupling layer system, which has an alternating sequence of at least two ?/4 mirror layers with different acoustic impedance. The coupling layer system furthermore has a compensation layer, which has an approximate thickness of ?/8. The compensation layer according to the invention makes it possible to match any discrepancy in the phase difference (which is caused by reflections on the mirror layers) from the predetermined 180° between the connections of the symmetrical port to approximately 180°.

Abstract: A piezoelectric thin film resonator having a stabilized temperature characteristic of resonant frequency, a method for manufacturing the same, and a communication apparatus using the piezoelectric thin film resonator are provided. The piezoelectric thin film resonator is provided with a substrate having an opening, first and second insulation films which are provided on one surface of the substrate while covering the opening and which primarily include SiO2 and Al2O3, respectively, Al2O3 having oxygen defect and being in an amorphous state, and a piezoelectric thin film which is provided on the second insulation film and is sandwiched between electrodes and which primarily includes ZnO.

Abstract: A megasonic cleaning system comprised of a container, a resonator, one or more piezoelectric crystals and a bonding layer comprised of indium or tin for attaching the piezoelectric crystal to the resonator. The resonator comprises a material selected from the group consisting of quartz, sapphire, silicon carbide, silicon nitride, aluminum, ceramics and stainless steel. The piezoelectric crystal may be attached directly to a side or to the bottom of the container, in which case the container acts as the resonator.

Abstract: An apparatus for fluid level measurement comprises an upright tube (10) extending into a storage tank (12) substantially the full height distance of the tank (12). An acoustic transducer (14) is positioned at the top of the tube (10) and adapted to emit a sound pulse to be bounced off the surface (16) of the fluid level within the tube (10) and to receive a reflected pulse. Means is provided for measurement of the time of arrival of the reflected sound pulse. An acoustic coupling means is provided for the transducer (14) to shape and increase the amplitude of the pulse emitted from the transducer (14) together with an increase in the amplitude of the voltage produced by the transducer (14) in response to the received reflected pulse.

Abstract: There is put forward a piezolectric element for converting pressure signals into electrical signals and vice versa, with a porous homogeneous ceramic body and with at least two electrodes attached to the ceramic body. The porous ceramic body comprises open pores and is preferably hermetically sealed on the whole surface with an elastic coating. Furthermore there is suggested an oscillation transducer with the piezolement which is accommodated in a housing. The piezolectric element is with one end face rigidly connected to the base of the housing. The other end face represents a surface which is sensitive to oscillations, which preferably is not covered by the housing. The volume of the housing is filled with a casting compound, wherein the piezolectric element is mechanically decoupled from the casting compound.

Abstract: A two-dimensional ultrasound phased array transducer includes an acoustic backing, a first circuit, which may be a flexible circuit disposed over the acoustic backing or a ground plane, an acoustically absorptive interface layer disposed over the flexible circuit, and a piezoelectric layer disposed over the interface layer. A matching layer may be disposed over the piezoelectric layer, and a second circuit, which may be a ground plane or a flexible circuit, may be disposed over the matching layer. The piezoelectric layer and the matching layer are diced by forming kerfs extending through these layers and at least partially into the interface layer. Extending the kerfs into the interface layer reduces cross-talk between elements, electrically isolates the elements, and facilitates manufacturing by reducing the precision required in controlling the depth of the cut.

Abstract: An ultrasonic probe has a strip-shaped piezoelectric unit having a uniform thickness and a grounding electrode formed on the top surface, a backing material, and an acoustic matching layer bonded on the top surface of the piezoelectric unit. A conductive film is formed on a protrusively curved top surface of the backing material for applying a signal thereto for driving the piezoelectric unit. A conductive adhesive is applied between the backing material and the bottom surface of the piezoelectric unit. The conductive adhesive has a thickness which varies along the longitudinal direction of the piezoelectric unit, thereby causing a larger driving current to flow at the center of the piezoelectric unit in the longitudinal direction, and a smaller driving current to flow at both ends of the piezoelectric unit to suppress side lobes in generated ultrasonic waves.

Abstract: A transmit pulser includes an H-bridge of four transistors. First and second transistors of the H-bridge connect with a first electrode of a transducer element, and third and fourth transistors of the H-bridge connect with a second electrode of the transducer element. A differential receive amplifier connects with the first and third transistors. First and second diode clamps connect with the first and third transistors, respectively, and the inputs to the differential receive amplifier. The second and fourth transistors connect to a same power or voltage source, imposing a same voltage in either a forward or a reverse direction. By using matched transistor pairs (e.g. first and third matched pair and second and fourth matched pair), symmetrical transmit waveforms are generated. Symmetrical transmit waveforms allow for using phase inversion or phase differences between transmit waveforms for imaging, such as for harmonic imaging of tissue.

Abstract: The invention relates to acoustic transducers which comprise a ceramic ring formed from a pre-stressed set of segments. It consists in using, as screws for tightening pre-stressing wedges, screws with hexagonal heads and in placing on the inner face of these wedges a plate provided with recesses in which the cants of these screw heads become anchored. This plate comprises transverse channels allowing the passage of the power supply wires for the sectors. The central screw is removed after the desired pre-stressing has been obtained. It makes it possible to improve the manufacture of these transducers.

Abstract: In an ultrasonic transceiver, an inner housing has a bottom portion, a first tubular side wall extending from one end surface of the bottom portion and a first flange portion formed on an outer peripheral portion of the first tubular side wall. The bottom portion and first tubular side wall provide a tubular cavity formed therebetween, and the piezoelectric member is mounted on the one end surface of the bottom portion in the tubular cavity. An outer housing has a second tubular side wall coaxially arranged around the outer peripheral portion of the first tubular side wall with a predetermined gap therebetween. The second tubular side wall is provided with one end portion which is opposite to one end surface of the first flange portion and contacted thereto. A first absorption member is inserted in the gap between the first tubular side wall and the second tubular side wall.