Abstract: A single chip transducer apparatus that includes on-chip electronic circuitry which, when connected properly to a two-dimensional matrix of ultrasonic transducer elements, provides enough information to an external imaging system to form three-dimensional images of the subject of interest. In a preferred embodiment, the circuitry provides an amplifier for each transducer element, and then conditions the output of the amplifier in several ways. In one embodiment of the invention, the elements' analog voltages are stored in a sample and hold circuit, and time multiplexed into a high speed line driver that sends many elements data down the interconnect to the system's high speed Analog to Digital converters. In another embodiment, the gain of the amplifiers can be controlled in time to provide aperture translation and time based expansion for translating and focusing image slices in the elevation direction.

Abstract: Disclosed is an ultrasonic transducer which is composed of a plurality of piezoelectric elements having an electrode on each of two opposite surfaces, an acoustic matching layer arranged on the first surface that is one of the two opposite surfaces, a wiring board so arranged on the acoustic matching layer as to be in contact with the piezoelectric element, and a conductor electrically connecting the wiring board with the electrode on the second surface that is one of the two opposite surfaces. This ultrasonic transducer is characterized in that the surface of the wiring board on the same side as the second surface of the piezoelectric element is positioned relatively lower than the second surface of the piezoelectric element.

Abstract: A method for manufacturing an acoustical stack for use within an ultrasound transducer comprises using a user defined center operating frequency of an ultrasound transducer that is at least about 2.9 MHz. A piezoelectric material and a dematching material are joined with an assembly material to form an acoustical connection therebetween. The piezoelectric material has a first acoustical impedance and *at least one of* an associated piezoelectric rugosity (Ra) and piezoelectric waviness (Wa). The dematching material has a second acoustical impedance that is different than the first acoustical impedance and at least one of an associated dematching Ra and dematching Wa. The piezoelectric and dematching materials have an impedance ratio of at least 2. The assembly material has a thickness that is based on the center operating frequency and at least one of the piezoelectric Ra, piezoelectric Wa, dematching Ra and dematching Wa.

Abstract: An ultrasound reactor (30) having a reactor body (1), a reactor tube (9) disposed within the reactor body and a magnetostrictor transducer (11) comprising at least one annular element (28a-d) concentric with, and mounted to an external wall of said tube and a process for ultrasonic treatment of a reaction material are disclosed. The transducer is mounted on the reactor tube in such a way so as to transmit ultrasound radiation to the interior of the tube and to induce an upwardly flowing cavitation stream whose longitudinal axis substantially coincides with a longitudinal axis of said tube, causing physical changes to the reaction material.

Abstract: Provided is an ultrasonic probe, which can be improved in quality, which can acquire characteristics of a high sensitivity and a wide band and which can acquire an ultrasonic image of a high resolution. In this ultrasonic probe, grooves (160) are formed and utilized to form piezoelectric elements (110) and first acoustic matching layers (121) in a curved shape thereby to converge ultrasonic waves without any acoustic lens. Moreover, signal conductors (150) are disposed on the signal electrode faces of the piezoelectric elements (110).

Abstract: A ultrasonic transducer of the invention comprises: a transducer cell including a first electrode and a second electrode disposed separated from the first electrode by an air gap portion; and an electret for applying a potential difference between the first electrode and the second electrode. The electret is disposed in a region where at least a part thereof does not overlap with the transducer cell when viewed from a transmitting direction of ultrasonic waves.

Abstract: A method for transmitting an ultrasonic wave is disclosed. The method includes: selecting a first combination of transmission elements from among multiple transmission elements, wherein the first combination of transmission elements includes at least two transmission elements adjacent to each other; and vibrating the transmission surfaces of the first combination of transmission elements in a substantially same phase to transmit the ultrasonic wave with a first directivity. The first directivity is different from a second directivity of the ultrasonic wave transmitted from single transmission element.

Abstract: The present invention provides an apparatus for sensing biometric information in a finger with piezo ceramic elements. In one embodiment, the apparatus includes an array of discrete piezo ceramic elements and filler. The array of discrete piezo ceramic elements is responsive to acoustic characteristics of parts of the finger. The filler is distributed between the discrete piezo ceramic elements and provides acoustic attenuation and electric isolation between the discrete piezo ceramic elements. A protective layer can receive a ridge pattern of the finger positioned proximate to the array. Air in valleys between ridges of the ridge pattern of the finger acts as an acoustic barrier. A backing layer (air or foam) can also be provided.

Abstract: A technique is provided by which energy is physically/mechanically transmitted down through a wellbore. The transmitted energy is directed downhole along a fluid channel and impinges on an energy converter positioned in the wellbore or at another subterranean location. The energy converter converts the physical energy into electrical energy that can be supplied to a downhole device.

Abstract: An ultrasound transducer includes an array of PZT elements mounted on a non-recessed distal surface of a backing block. Between each element and the backing block is a conductive region formed as a portion of a metallic layer sputtered onto the distal surface. Traces on a longitudinally extending circuit board—preferably, a substantially rigid printed circuit board, which may be embedded within the block—connect the conductive region, and thus the PZT element, with any conventional external ultrasound imaging system. A substantially “T” or “inverted-L” shaped electrode is thereby formed for each element, with no need for soldering. At least one longitudinally extending metallic member mounted on a respective lateral surface of the backing block forms a heat sink and a common electrical ground. A thermally and electrically conductive layer, such as of foil, transfers heat from at least one matching layer mounted on the elements to the metallic member.

Abstract: An underwater acoustic projector comprising one or more cylindrical shell segments (8), each shell segment (8) having an even number of drivers (10) mounted therein, and the method of manufacturing said projector. The shell segments (8) preferably are formed with a longitudinal slot (14) and have arcuate segments (16), preferably of a dielectric material extending along the sides of the slot (14) for retaining the drivers (10) within the shell segments (8). The combined lengths of the driver is between 70% and 90% of the shell segment (8) length.

Abstract: An ultrasonic sensor includes a piezoelectric element and an acoustic matching member that are joined together to form an ultrasonic detector base. The ultrasonic detector base is sectioned by a clearance extending in an ultrasonic propagation direction to form multiple ultrasonic detectors arranged in an array. The clearance does not entirely section the ultrasonic detector base so that the ultrasonic detectors are joined together by a portion of the ultrasonic detector base.

Abstract: An ultrasonic transducer (101, 102, 103) includes: a front member (1, 1a) having a front side on which an ultrasonic radiating surface (11) is provided and a back side which is opposite to the front side; a side member (2, 2a); a backing member (3, 3a); and a piezoelectric ceramic body (4), which are provided axially integrally, wherein one end side of the side member (2, 2a) is fitted to the back side of the front member (1, 1a), one end side of the backing member (3, 3a) is fitted to another end side of the side member (2, 2a), and the piezoelectric ceramic body (4) is interposed between the front member (1, 1a) and the backing member (3, 3a).

Abstract: The object is to make it possible to check the operating state such as degradation in sensitivity of an AE sensor when it is used actually. There are provided an AE conversion element 41, a pulse signal transmitter 42 for applying a pulse signal to the AE conversion element through the output passage of an AE signal from AE conversion element 41, a receiver/processor 43 for converting the AE signal into a digital signal and calculating the frequency characteristics by processing the digital signal, a reference frequency characteristic storage section 44 for storing the frequency characteristics of the AE signal of the AE conversion element in the reference state as reference frequency characteristics, and a comparator 45 for comparing the frequency characteristics of the AE signal calculated in response to an operation check request signal with the reference frequency characteristics.

Abstract: A method for producing a piezoelectric thin-film resonator includes forming a sacrificial layer on a substrate, performing a plasma treatment on the sacrificial layer so that the surface roughness (Ra) of end surface portions of the sacrificial layer is about 5 nm or less, forming a strip-shaped dielectric film so as to be continuously disposed on the surface of the substrate and the end surface portions and the principal surface of the sacrificial layer, forming a piezoelectric thin-film area including a lower electrode, an upper electrode, and a piezoelectric thin-film disposed therebetween so that a portion of the lower electrode and a portion of the upper electrode surface each other at an area on the dielectric film, the area being disposed on the upper portion of the sacrificial layer, and removing the sacrificial layer to form an air-gap between the substrate and the dielectric film.

Abstract: A piezoelectric actuator comprised of a multi-layered construction of piezoelectric layers interleaved with inner electrodes in which the inner electrodes are contacted on alternating sides by outer electrodes and the regions between the outer electrodes are provided with a suitable insulation has an insulating layer which is comprised of a material with properties virtually identical to those of the piezoelectric layers which is applied to the external surface of the piezoelectric actuator in the region between the outer electrodes.

Abstract: In an ultrasound transducer arrangement comprising at least one piezoelectric body with a lower and an upper electrode and a coupling layer including a wafer on which the ultrasound transducers are disposed and are connected to the lower electrode, a conductor structure of uniform height is disposed on the wafer and is in contact with the lower electrode and any space between the piezoelectric body and the wafer is completely filled with a cement material.

Abstract: A multi-dimensional transducer array is provided. The multi-dimensional transducer array includes a plurality of elements. First and second kerfs acoustically separate the elements. A first width of the first kerf is larger than a second width of the second kerf.

Abstract: A curved two-dimensional array transducer includes a layer of piezoelectric material overlaying a layer of ASICs which is attached to a backing wing. The piezoelectric material is diced in orthogonal azimuth and elevation directions to form a two-dimensional array of transducer elements, with the dicing cuts in the elevation direction extending through the ASIC layer so that the piezoelectric layer and the ASIC layer can be bent in the azimuth direction. The backing wing provides a flexible substrate which can be bent while supporting the ASIC layer and piezoelectric elements. In a second example the piezoelectric layer and ASIC layer are attached to opposite sides of flex circuit which provides the flexible substrate after the piezoelectric layer and ASIC layer are diced.

Abstract: Ultrasonic transducer module comprises at least one transmitter layer, at least one receiver layer and at least one ground plane. The transmitter layer and the receiver layer comprise a number of elongated transmitter and receiver electrodes, the electrodes being arranged in parallel within each layer, the transmitter layers and the receiver layers are parallel, and the electrodes of the receiver layers make an angle greater than zero with the electrodes of at least one of the transmitter.

Abstract: An electroacoustic transducer having a tail mass, a head mass and at least two parallelepiped shaped piezoelectric material elements disposed between and attached to the tail mass and the head mass is provided. The tail mass has a body extending between a first end and a second end, the body having a cavity with a cavity wall and the cavity extending from the first end towards the second end. The head mass has a head and an elongated shaft attached to and extending from the head, the shaft having a shaft axis and being located at least partially within the cavity of the tail mass. The at least two parallelepiped shaped piezoelectric material elements are made from a piezoelectric material having a non-zero d3y shear piezoelectric coefficient where the d3y coefficient can be d34, d35 or d36.

Abstract: An ultrasonic sensor having a piezoelectric element including first and second electrodes is disclosed. The ultrasonic sensor includes an aluminum case having a bottom part electrically contacting the second electrode of the piezoelectric element, a first conductive part electrically connected to the first electrode of the piezoelectric element, and a second conductive part having a cladding material including a material exhibiting a satisfactory welding property with respect to the aluminum case. The second conductive part and the aluminum case are welded together.

Abstract: An ultrasonic sensor with stabilized transmitting/receiving characteristics capable of achieving a desired directivity easily and at low cost and a method for manufacturing the same are provided. The ultrasonic sensor includes a base composed of a synthetic resin. The base includes a cylindrical side portion and a ring-shaped bent portion extending inward from a first opening of the side portion. A ring-shaped recessed portion is provided in the inner surface of the bent portion adjacent to the end of the bent portion. A piezoelectric element is disposed on the recessed portion. A sound absorber and a weight are fitted and fixed in the base. An outer casing composed of a synthetic resin is provided so as to cover the outer surface of the piezoelectric element and the outer surface of the base.

Abstract: A longitudinally driven slotted transducer has a tubular member with an axial slot extending from one end to the other end. A drive assembly is disposed across the inner wall of the tubular member and supported by journal bearing surfaces extending from opposing sides of the inner wall to locate the drive assembly in a position offset from the longitudinal central axis of the tubular member. The interface between the drive assembly and tubular member comprises a layer of solid lubricant material mounted on the journal bearing type surfaces.

Abstract: An ultrasonic motor is provided with an ultrasonic transducer having a piezoelectric element, a holding member fixed to the ultrasonic transducer and holding the ultrasonic transducer, a pressing member pressing the holding member, and a member to be driven which is driven by frictional force between the member to be driven and the ultrasonic transducer. The pressing member has a hole portion and the holding member has a protruding portion engaged with the hole portion in a direction of pressing conducted by the pressing member. The hole portion and the protruding portion abut on each other so that the pressing member presses the member to be driven via the holding member and the ultrasonic transducer, thereby driving the member.

Abstract: The present invention relates to composite piezoelectric apparatus, transducers and methods of manufacture. In an embodiment, a composite piezoelectric apparatus has a sacrificial base and pillar array. Different volume percents of piezoelectric material are used in the sacrificial base and pillar array. A first volume percent in the base is lower than the second volume percent in the pillar array. In this way, the sacrificial base can be easily removed from the pillar array after the base and pillar array are sintered in the manufacture of a final composite piezoelectric transducer. A method of manufacturing a composite piezoelectric transducer from a sacrificial base and pillar array and a composite piezoelectric transducer made by the method are provided. A composite piezoelectric transducer stack is provided.

Abstract: The ultrasonic operating apparatus includes an ultrasonic transducer that generates ultrasonic vibrations, and a probe that has a distal end portion and a proximal end portion, the proximal end portion being coupled to the ultrasonic transducer, and to which ultrasonic vibrations output from the ultrasonic transducer are transmitted, where the probe has a probe main body having a length of an integral multiple of about a half wavelength of the ultrasonic vibrations and an adjusting portion that changes a weight and a dimension of the probe main body to adjust a resonance frequency of the probe main body.

Abstract: A touch sensor having an acoustic substrate, an acoustic transducer, and an acoustically diffractive grating is provided. The grating is disposed between the transducer and the substrate, so that acoustic energy from the transducer is coupled to an acoustic wave propagating along the surface of the substrate. If used in a display device, the combination of the transducer and grating may provide a low profile that allows the assembly to be more easily placed between the acoustic substrate and a bezel placed in front of the substrate. No acoustic components need be mounted on the rear surface of the substrate, allowing the acoustic substrate to be formed on the front surface of the display device.

Abstract: A lower electrode is formed over a semiconductor substrate via an insulator film, first and second insulator films are formed to cover the lower electrode, an upper electrode is formed over the second insulator film, third to fifth insulator films are formed to cover the upper electrode and a void is formed between the first and second insulator films between the lower and upper electrodes. An ultrasonic transducer comprises the lower electrode, the first insulator film, the void, the second insulator film and the upper electrode. A portion of the first insulator film contacting with the lower electrode is made of silicon oxide, a portion of the second insulator film contacting with the upper electrode is made of silicon oxide and the first or second insulator film includes a silicon nitride film positioned between the upper and lower electrodes and not in contact with the upper and lower electrodes.

Abstract: A piezoelectric transducer (10) includes (a) a first gas matrix piezoelectric composite (12) having a side including at least one positive pole (+) and another side including at least one negative pole (?); (b) a second gas matrix piezoelectric composite (14) having a side including at least one positive pole (+) and another side including at least one negative pole (?); and (c) a substrate (28) having a first side (22) and a second side (24), wherein the substrate is positioned between the first gas matrix piezoelectric composite and the second gas matrix piezoelectric composite. Either the first or second gas matrix piezoelectric composite may include a plurality of piezoelectric rods (15), wherein each piezoelectric rod includes at least one positive pole (16) end and at least one negative pole end (18).

Abstract: A piezoelectric micromachined ultrasonic transducer comprising a substrate and a first dielectric film formed on the substrate. An opening having a sidewall is formed through the substrate and first dielectric film. A bottom electrode is formed on the first dielectric film spanning the opening. A piezoelectric element is formed on the bottom electrode. A second dielectric film surrounds the piezoelectric element. A conformal insulating film is formed on the sidewall of the opening. A conformal conductive film is formed in contact with the bottom electrode and on the sidewall of the opening, wherein an open cavity is maintained in the opening. A top electrode is formed in contact with the piezoelectric element.

Abstract: An ultrasonic transducer device comprising: an ultrasonic transducer array micromachined on a substrate; flexible electrical connections connected to the transducer array; and a body of acoustically attenuative material that supports the substrate and the flexible electrical connections. The acoustic backing material may contain additional features, such as tabs or notches, for use in positioning the transducer on fixtures during manufacturing or positioning the transducer within a housing during final assembly. Tabs or other features that are used only during manufacturing may be subsequently removed from the device. The MUT device itself may also be thinned so as to provide flexibility as desired. The backing material is preferably matched in acoustic impedance to the silicon wafer so as to prevent reflection at the interface of any acoustic energy propagating rearward, i.e., in the direction away from the device front surface.

Abstract: The invention provides a multi-frequency transducer capable of obtaining desired directivity regardless of frequencies. Parallelepiped-shaped transducer elements (1) are used as transducer elements and a plurality of such transducer elements (1) are arranged in an array. The transducer elements (1) are caused to resonate using a resonant frequency in fundamental vibration mode and a resonant frequency in harmonic vibration mode determined by the dimensions (A, B) of a short edge (1a) and a long edge (1b) perpendicular to a longitudinal edge (1c) of each transducer element (1) to transmit and receive at multiple frequencies. The angle of directivity (?) of the transducer elements is controlled by the dimension (C) of the longitudinal edge which is set to a value which does not affect resonance in either the fundamental vibration mode or the harmonic vibration mode.

Abstract: A device for scanning a biological object, such as a fingerprint, is disclosed. One such device includes an array of acoustic waveguides and a piezoelectric array device. The piezoelectric array devices may be arranged in association with the waveguide array to provide ultrasonic energy in the form of an ultrasonic wave or collection of waves to the waveguide array, and also arranged to receive ultrasonic energy in the form of an ultrasonic wave or collection of waves from the waveguide array. The acoustic energy received by the piezoelectric array from the waveguide array may be energy that has been reflected from the biological object. A waveguide array according to the invention uses internal reflection to transmit the acoustic wave from one end of the waveguide array to another end of the waveguide array.

Abstract: Ultrasonic transducer including a multi-layer transformer arranged between a backing block and piezoelectric layer on each of which at least one matching layer is arranged. The transformer includes a substrate having an electronic circuit, one or more acoustically active layers and an interconnect layer interposed between the piezoelectric layer and the substrate. The properties of the substrate, each acoustically active layer and the interconnect layer are selected and then the acoustic impedance of the transformer at a side of the piezoelectric layer adjacent the transformer is determined. The properties are then varied, e.g., using a computer simulation, until values for these properties are obtained which provide a desired acoustic performance characteristic at the side of the piezoelectric layer adjacent the transformer. The electronic circuit is thus considered in the determination of the acoustic impedance of the transformer.

Abstract: Ultrasonic probe comprising an elongate body having a first end and a second end, an ultrasonic transducer attached to the probe at or adjacent the first end, and an enlarged support section intermediate the ultrasonic transducer and the second end, wherein the enlarged support section has an equivalent diameter greater than an equivalent diameter of the body at any location between the enlarged support section and the ultrasonic transducer. The probe may be used to introduce ultrasonic energy into ultrasonic cleaning systems.

Abstract: A method for producing a piezoelectric thin-film resonator includes forming a sacrificial layer on a substrate, performing a plasma treatment on the sacrificial layer so that the surface roughness (Ra) of end surface portions of the sacrificial layer is about 5 nm or less, forming a strip-shaped dielectric film so as to be continuously disposed on the surface of the substrate and the end surface portions and the principal surface of the sacrificial layer, forming a piezoelectric thin-film area including a lower electrode, an upper electrode, and a piezoelectric thin-film disposed therebetween so that a portion of the lower electrode and a portion of the upper electrode surface each other at an area on the dielectric film, the area being disposed on the upper portion of the sacrificial layer, and removing the sacrificial layer to form an air-gap between the substrate and the dielectric film.

Abstract: Disclosed is an acoustic backing composition comprising an ethylene-vinyl acetate copolymer containing 20 to 80% by weight of the vinyl acetate units and a filler contained in the ethylene-vinyl acetate copolymer.

Abstract: An ultrasonic probe realizing a high sensitivity and a wide band thereof while miniaturizing a transducer and also taking into consideration a measure against generated heat. The ultrasonic probe includes: a backing material; a transducer array having a multi-layered structure in which a plurality of transducers are arranged in a first direction to compose a transducer group and a plurality of the transducer groups are arranged in a second direction different from the first direction; a first layer of conductive resin electrically connecting the first electrode layers of adjacent transducers with each other in each transducer group; a second layer of conductive resin electrically connecting the internal electrode layers of adjacent transducers with each other in each transducer group; and an insulating resin disposed in a predetermined region among the plurality of transducers in each transducer group.

Abstract: An ultrasonic sensor according to the present invention is used, for example, for detecting an obstacle positioned in front of an automotive vehicle. The ultrasonic sensor includes an piezoelectric element connected to an acoustic matching member and a processing circuit, all contained in a casing. Ultrasonic waves reflected on an object are received by the acoustic matching member and converted into electrical signals in the piezoelectric element. The electrical signals are processed in the processing circuit to thereby detect a distance to the object and/or positions of the object. A surface of the acoustic matching member connected to the piezoelectric element is made larger than the piezoelectric element to form an overhang area on a conductive layer formed on the acoustic matching member. In this manner, electrical connection in the ultrasonic sensor is easily made, and detection sensitivity of the ultrasonic sensor is enhanced.

Abstract: An acoustic driver assembly for use with any of a variety of cavitation chamber configurations, including spherical and cylindrical chambers as well as chambers that include at least one flat coupling surface, is provided. The acoustic driver assembly includes at least one transducer, a head mass and a tail mass. The end surface of the head mass is shaped so that only a ring of contact is made between the outer perimeter of the head mass of the driver assembly and the cavitation chamber to which the driver is attached. The area of the contact ring is controlled by shaping its surface.

Abstract: An acoustic driver assembly for use with any of a variety of cavitation chamber configurations, including spherical and cylindrical chambers as well as chambers that include at least one flat coupling surface. The acoustic driver assembly includes at least one transducer, a head mass and a tail mass. The end surface of the head mass is shaped to limit the contact area between the head mass of the driver assembly and the cavitation chamber to which the driver is attached, the contact area being limited to a centrally located contact region. The area of contact is controlled by limiting its size and/or shaping its surface.

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 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: An ultrasonic transducer includes a cylindrical cap member having a bottom. A piezoelectric element is bonded to the inner side of a bottom portion of the cap member using a conductive adhesive or other suitable adhesive. An inner frame made of a material having an acoustic impedance greater than that of the cap member is fitted into the cap member so as to be in contact with a side portion, including the end portion, of the cap member. Through-holes are provided in the side portion of the inner frame. Lead wires are connected to the piezoelectric element and the inner frame, respectively. A sound absorber and a damper are inserted into the inner frame. The damper is in direct contact with the side portion of the cap member via the through-holes of the inner frame.

Abstract: An electroacoustic transducer having one end portion of a first piezoelectric element and one end portion of a second piezoelectric element fixed to a frame such that the first piezoelectric element and the second piezoelectric element are supported by the frame in an opening of the frame in the cantilever manner. A flexible thin film is bonded to the frame and the first and second piezoelectric elements so that it covers at least a gap between each of the piezoelectric elements and the frame. The other end portions of the piezoelectric elements are free end portions, and face each other with a gap therebetween.

Abstract: The present invention relates to a process for producing a block of low-frequency piezoelectric composite material having rows of superposed ceramic posts embedded in a dielectric. This process includes the production of the block of composite material from two superposed identical half-blocks, produced by cutting into a single pre-machined piezoelectric ceramic block. According to the invention, the block of ceramic material thus constituted is then machined so as to form a structure comprising rows of aligned posts, each post being formed from two elementary posts facing each other in strict alignment. The ceramic structure thus produced is then integrated into an appropriate dielectric matrix. The block thus produced is intended to be used for manufacturing acoustic transducers from composite materials. The invention relates in particular to the field of sonar detectors designed to detect objects located at a relatively short distance from the detector.

Abstract: According to one embodiment of the invention, an acoustic mirror structure situated in a bulk acoustic wave structure includes a number of alternating low acoustic impedance and high acoustic impedance layers situated on a substrate. Each high acoustic impedance layer includes a first mole percent of a primary metal and a second mole percent of a secondary metal, where the first mole percent of the primary metal is greater than the second mole percent of the secondary metal, and where the secondary metal causes each high acoustic impedance layer to have increased resistivity. According to this exemplary embodiment, the second mole percent of the secondary metal can cause only a minimal decrease in density of each high acoustic impedance layer. The increased resistivity of each high acoustic impedance layer can cause a reduction in electrical loss in the bulk acoustic wave structure.

Abstract: A sonic or ultrasonic transducer, which is embodied as a radial oscillator. So that the sonic or ultrasonic transducer can be used at high temperatures, a matching layer is located between the radial oscillator and the atmosphere into which the ultrasonic signals are transmitted The matching layer is made from a material that has a dimensional stability up to a temperature which lies above the temperature at the installation location of the sonic or ultrasonic transducer. Furthermore, the matching layer is selected such that its material-specific coefficient of thermal expansion is greater than that of the materials of a piezoelectric unit and a coupling ring, and that the modulus of elasticity of the material of the matching layer is at least one order of magnitude smaller than that of the piezoelectric unit and/or the coupling ring.

Abstract: Techniques for fabricating high frequency ultrasound transducers are provided herein. In one embodiment, the fabrication includes depositing a copperclad polyimide film, a layer of epoxy on the copperclad polyimide film, and a polyvinylidene fluoride film on the epoxy. The assembly of materials are then pressed to bond the polyvinylidene fluoride film to the copperclad polyimide film and to form an assembly. The polyvinylidene fluoride film being one surface and the copperclad polyimide film being the other surface. The area behind the copperclad polyimide film surface is filled with a second epoxy, and then cured to form an epoxy plug.

Abstract: The present invention is directed to a high-powered (e.g., >500 W) ultrasonic generator for use especially for delivering high-power ultrasonic energy to a varying load including compressible fluids. The generator includes a variable frequency triangular waveform generator coupled with pulse width modulators. The output from the pulse width modulator is coupled with the gates of an Isolated Gate Bipolar Transistor (IGBT), which amplifies the signal and delivers it to a coil that is used to drive a magnetostrictive transducer. In one embodiment, high voltage of 0-600 VDC is delivered across the collector and emitter of the IGBT after the signal is delivered. The output of the IGBT is a square waveform with a voltage of +/?600V. This voltage is sent to a coil wound around the ultrasonic transducer. The voltage creates a magnetic field on the transducer and the magnetorestrictive properties of the transducer cause the transducer to vibrate as a result of the magnetic field.