Abstract: A plurality of application specific integrated circuit (ASIC) chips with different functions is provided. Each of the ASICs performs one or more functions along an ultrasound data path. The chips include communications protocols or processes for allowing scaling. For example, ASICs for backend processing include data exchange ports for communicating between other ASICs of the same type. As another example, receive beamformer ASICs cascade for beamformation. By providing ASICs implementing many or most of the ultrasound data path functions, with scalability, the same ASICs may be used for different system designs. A family of systems from high end to low-end using the same types of ASICs, but in different configurations, is provided.

Abstract: Making a transducer having a plastic matching layer which includes providing a transducer housing having a proximal end and a distal end, and bonding a plastic to the distal end of the transducer housing (the plastic fluidly sealing and occluding the distal end). The bonding further includes inserting a cylinder comprising a mold-release chemical into the transducer housing, bonding plastic onto the distal end of the transducer housing, and removing the cylinder when the plastic has hardened.

Abstract: An electroacoustic transducer, particularly for underwater use, having a ceramic body (10) and a pair of electrodes, whose flat electrodes (11, 12) are arranged on mutually averted end faces (101, 102) of the ceramic body (10). At least one electrode (11) is structured in order to effectively suppress the side-lobes in the directional characteristic for all spatial directions such that the density of the ceramic body (10) decreases from the body center to the body edge.

Abstract: A diagnostic ultrasonic probe for use in body cavities has at its tip an ultrasonic transducer array, which has a layered structure wherein a flexible circuit board, an electric circuit, a backing material, a piezoelectric element array, an acoustic impedance matching layer and an acoustic lens are formed atop another on a supporting member. The electric circuit includes at least one of amplifiers for amplifying echo signals from ultrasonic transducers, switches for switching over between sending the echo signals from the ultrasonic transducers and receiving drive signals for exciting the ultrasonic transducers, a multiplexer for selective-switching between the echo signals as well as between the drive signals, an A/D converter for converting the echo signals from an analog form to a digital form, and a D/A converter for converting the drive signals from a digital form to an analog form.

Abstract: A capacitive ultrasonic transducer includes a flexible layer, a first conductive layer on the flexible layer, a support frame on the first conductive layer, the support frame including a flexible material, a membrane over the support frame being spaced apart from the first conductive layer by the support frame, the membrane including the flexible material, a cavity defined by the first conductive layer, the support frame and the membrane, and a second conductive layer on the membrane.

Abstract: A slotted cylinder acoustic transducer has a crescent-shaped insert disposed between a ceramic stack assembly and s cylindrical housing shell. In some embodiments, all of the ceramic elements in the ceramic stack assembly can have the same shape.

Abstract: Unipolar, bipolar or sinusoidal transmitters may leave the transmitter in any of various states at the end of one pulse. Undesired acoustic energy may be generated to change states prior to beginning another transmit sequence or pulse. For example, phase inversion for tissue harmonic imaging is performed where two sequential pulses are transmitted with different phases. The first waveform starts at a low state and ends at the low state of a unipolar transmitter. The next waveform starts at the high state. Transmit apodization or spectrum control techniques may require a pattern of waveform starting states different than a current state. Acoustic disruption due to a change of state of the transmitter between transmissions for imaging is minimized.

Abstract: A method of fabricating a polymer-based capacitive ultrasonic transducer, which comprises the steps of: (a) providing a substrate; (b) forming a first conductor on the substrate; (c) coating a sacrificial layer on the substrate while covering the first conductor by the same; (d) etching the sacrificial layer for forming an island while maintaining the island to contact with the first conductor; (e) coating a first polymer-based material on the substrate while covering the island by the same; (f) forming a second conductor on the first polymer-based material; (g) forming a via hole on the first polymer-based material while enabling the via hole to be channeled to the island; and (h) utilizing the via hole to etch and remove the island for forming a cavity.

Abstract: An acoustic projector which includes an outer shell (8) formed of a reinforced epoxy resin having a longitudinal slot (14) has an inner reinforcing liner (20) formed of metal to reduce stress. The liner (20) extends throughout the length of the outer shell and has a longitudinal slot (22) aligned with the slot (14) formed in the shell (8). An arcuate shaped driver (10) is mounted along a portion of the I.D. of the metal liner (20) and separated therefrom by insulation (24).

Abstract: An apparatus for producing pressure oscillation of a fluid, incorporating hermetically sealed casing including a housing, a cover, a hermetic seal, a cylindrical flextensional transducer driven by piezoelectric or magnetostrictive driving member positioned in the inner cavity of the transducer and secured between two endplates, two springs providing for axial preloading and centering of the cylindrical flextensional transducer, two internal seals preventing fluid leakage between swept volume and other structure volumes; hermetic connectors for electrical connecting of the actuation member to energizing means, and fluid flow channel.

Abstract: A piezoelectric element suitable for use as a sensor element in a hydrophone. In a preferred embodiment, the sensor element comprises a ceramic lead zirconate titanate substrate defining opposed ends and including at least first and second conductive strip electrodes on opposed top and bottom faces thereof. In accordance with the invention, at least one of the strip electrodes, and preferably at least the end of one of the strip electrodes disposed adjacent one of the opposed ends of the substrate, includes one or more spaced-apart laser cuts created during the manufacture of the sensor element for presetting the capacitance of the sensor element.

Abstract: An electroacoustic transducer, particularly for underwater use, having a ceramic body (10) and a pair of electrodes, whose flat electrodes (11, 12) are arranged on mutually averted end faces (101, 102) of the ceramic body (10). At least one electrode (11) is structured in order to effectively suppress the side-lobes in the directional characteristic for all spatial directions such that the density of the ceramic body (10) decreases from the body center to the body edge.

Abstract: Thermal expansion matching for an acoustic telemetry system. An acoustic telemetry system includes at least one electromagnetically active element and a biasing device which reduces a compressive force in the element in response to increased temperature. A method of utilizing an acoustic telemetry system in an elevated temperature environment includes the steps of: applying a compressive force to at least one electromagnetically active element of the telemetry system; and reducing the compressive force as the temperature of the environment increases.

Abstract: Systems and methods of a transducer having a plastic matching layer. At least some of the illustrative embodiments are transducers comprising a housing (having a proximal end, a distal end and an internal volume, the housing configured to couple to a spoolpiece of an ultrasonic meter), a plastic matching layer that has an external surface and an internal surface (the plastic matching layer seals to and occludes the distal end of the housing), and a transducer element abutting the internal surface of the plastic matching layer.

Abstract: A marine vibrator that in a particular embodiment includes a substantially elliptically shaped outer shell, a driver having a first and second end, at least one outer spring connected between the first end and the second end of the driver, and at least one inner spring connected between the first end and the second end of the driver. One or more masses are attached to the inner spring. At least one transmission element connects the outer spring and the outer shell. The outer and inner springs and the masses attached to the inner spring are selected to generate a first resonance frequency and a second resonance within the frequency range between 1 Hz and 300 Hz.

Abstract: An apparatus for producing pressure oscillation of a fluid, incorporating hermetically sealed casing including a housing, a cover, a hermetic seal, a cylindrical flextensional transducer driven by piezoelectric or magnetostrictive driving member positioned in the inner cavity of the transducer and secured between two endplates, two springs providing for axial preloading and centering of the cylindrical flextensional transducer, two internal seals preventing fluid leakage between swept volume and other structure volumes; hermetic connectors for electrical connecting of the actuation member to energizing means, and fluid flow channel.

Abstract: A ultrasonic cleaning system includes a tank composed of quartz or silicon carbide and one or more sleeved ultrasonic transducers mounted to the tank. The sleeved ultrasonic transducer has a two-part head mass, including a threaded sleeve and an outer housing that are composed of different materials. The threaded sleeve is preferably a metal that provides superior thread strength for mating with a compression bolt, while the outer housing is preferably silicon carbide or other ceramic material that provides a good thermal expansion match to the tank to facilitate adhesive bonding of the transducer to the tank.

Abstract: The integrated unmanned, affordable, microsystem in accordance with the present invention is used to deploy physical or chemical sensors for continuous monitoring of sea space over large time periods. The microsystem is capable of measuring ocean physical parameters over large time spans weeks, with higher accuracies and resolution and at significantly lower costs that the other sensors currently known in the art.

Abstract: A piezoelectric transducer defined by two faces comprises a plurality of piezoelectric cylinders. The axial length and composition of the piezoelectric cylinders determines the frequency of the transducer when excited. The axial ends of the piezoelectric cylinders are aligned with the faces. The piezoelectric cylinders are separated from each other and the space therebetween is fully or partially empty such that crosstalk between piezoelectric cylinders is substantially eliminated. Electrodes are produced at the faces of the transducer for simultaneously exciting the piezoelectric cylinders.

Abstract: The invention utilizes multiple frequency ultrasound generators driving multiple frequency harmonic transducer arrays at sweeping frequencies into the megasonic range. Generator signals that increase cavitation efficiency and that have successive time periods with predominantly stable cavitation and predominantly transient cavitation further improve the performance of the cleaning, microbiological inactivation, sonochemistry or processing systems. Probes that monitor the ultrasound and feedback the information to the generator provide consistency of process.

Abstract: A transducer assembly may comprise a thickness-mode piezoelectric ceramic body, a pair of foil conductors with mesh end portions, and a coupling medium used to fill in the interstices in the meshes. The foil conductors are held in contact with the electrode layers by a selected combination of adhesive mechanical clamping forces. One of the conductors is placed between one face of the ceramic body and a window that separates the transducer assembly from a fluid to be measured. The other conductor is held between the other face of the ceramic body and a backing body, which may be an acoustic isolator or a resonant isolating structure comprising a resonant body and an acoustic mass that is substantially heavier than the ceramic element.

Abstract: A combination transducer and water-blocking film for acoustic signaling through ambient water. The water-blocking film has an etched fluoropolymer film and adjacent bonding film interposed between the transducer and the water. Potting material extends adjacent to and is bonded to both sides of the water-blocking film. The film and potting material create an acoustic window. The etched fluoropolymer film is approximately one to two thousandths inch thick and the bonding film is approximately one thousandths inch thick, and the potting material is a polyurethane matrix.

Abstract: The invention concerns an ultrasonic transducer, which is assembled from several parts. These parts are a protecting plate, a piezoelectric disc and a housing. Joining of the parts for transducers are normally done by means of TIG welding or laser welding, but these are relatively costly processes, which also has an impact on the transducer, especially the piezoelectric disc, due to the heat. In order to reduce the heat load and simultaneously simplify manufacturing an ultrasonic transducer is suggested, in which the protecting plate and the housing consists of electrically conducting materials of different kinds and where joining of housing and plate is done by using a mechanical force influence and an electrical current which flows through plate and housing. Also, a method for joining the parts of an ultrasonic transducer is described.

Abstract: A communication control method used in a cellular mobile communication system in which each base station can radiate radio wave beams to a plurality of directions and each base station communicates with mobile stations by using the same frequency is provided in which the method includes the step of: controlling first timing at which a base station radiates a first radio wave beam such that the first timing is different from second timing at which another base station radiates a second radio wave beam which may cause interference with the first radio wave beam.

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: 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: 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 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 less 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: 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 in contact with 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 surface contact between the driver assembly and the chamber.

Abstract: A composite piezoelectric element has a layered configuration of a plurality of unit composite sheets. Each of the unit composite sheets includes a resin layer and a plurality of columnar piezoelectric elements arranged on the resin layer.

Abstract: A multi-port projector of acoustic energy in water includes a cylindrical hollow transducer having open annular ends. A thin, flexible member is secured to each annular end to extend across each opening to be displaced by the transducer, and the transducer and flexible members form an interior sealed from ambient water. A battery/electronics module is in the interior and is spaced from the transducer and flexible members to couple driving signals to the transducer for reciprocally displacing it and the flexible members in response to the driving signals. An inert liquid fills the interior around the module, and an open truss on each annular end exposes the flexible members to the ambient water. Cylindrical portions coaxially extending with the transducer on a common longitudinal axis are connected to the open trusses for projecting acoustic energy of lower frequency than conventional cylindrical transducers of similar size.

Abstract: A method for producing transducers having a 1-3 composite structure. The transducer element includes a plurality of thin piezoceramic wafers which are electroded on opposing major surfaces. The spaced wafers are separated by a passive polymer layer in a composite structure and the electrodes on the opposing major surfaces are connected to different ones of top and bottom electrode surfaces.

Abstract: An ultrasonic transducer system has at least one ultrasonic transducer. Each ultrasonic transducer includes a housing having a wall that is made at least in part of an organic structural material that is substantially impervious to water; and an ultrasonic sensor element located at least in part within the housing and positioned to transceive ultrasonic signals. The wall is preferably cylindrical in shape and made of polyvinylchloride plastic. An electrically grounded shield is within the housing and adjacent to an interior wall surface. The ultrasonic sensor element may be a piezoelectric copolymer film ultrasonic sensor element.

Abstract: A compound electro-acoustic transducer for producing acoustic signals has a plurality of elements. Each element has a piezoelectric disk with electrically conductive plates fixed on the top and bottom sides of the piezoelectric disk. A stud is joined to an outer face of each plate. Conductors can be joined to each stud. The elements can be assembled on a resilient structure to form an array. Elements can be used in the array or individually accessed.

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: An underwater wide-band electroacoustic transducer and a method of packaging the transducer. The underwater wide-band electroacoustic transducer comprises of several groups of piezoelectric ceramic units and acoustic window material. To produce the underwater wide-band electroacoustic transducer, groups of piezoelectric ceramic units each having a different dimension are assembled such that each ceramic unit separates from each other by different distances. The frequency response of each ceramic unit groups are added together to provide a wide-band frequency response. The acoustic window material is injected to joins the ceramic unit groups together into a package.

Abstract: An oscillator (2) capable of oscillating signals of specified frequencies in dipped state in liquid, comprising a diaphragm of piezoelectric material (9) having a front surface (9a), a rear surface (9b), and a side surface (9c), a first electrode (10A) installed on the front surface (9a) of the diaphragm (9), a second electrode (10B) installed on the rear surface of the diaphragm (9), and a covering material (6) for covering at least the rear surface (9b) side of the diaphragm (9), wherein an opening (14) is provided in the covering material (6), the first electrode (10A) comes into contact with the liquid with the oscillator (2) dipped in the liquid, gas is held in a space (23) formed of the rear surface (9b) and the covering material (6), and the opening (14) is allowed to communicate with the space (23), whereby, even if the liquid temperature varies, the oscillation frequencies can be stabilized in a rather short time.

Abstract: An underwater wide-band electroacoustic transducer and a method of packaging the transducer. The underwater wide-band electroacoustic transducer comprises of several groups of piezoelectric ceramic units and acoustic window material. To produce the underwater wide-band electroacoustic transducer, groups of piezoelectric ceramic units each having a different dimension are assembled such that each ceramic unit separates from each other by different distances. The frequency response of each ceramic unit groups are added together to provide a wide-band frequency response. The acoustic window material is injected to joins the ceramic unit groups together into a package.

Abstract: An underwater acoustic transducer includes a set of formed substrates of piezoelectric polymer composite, the formed substrates having at least a first and second surface. Conductive electrodes are deposited on the first and second sides of the formed substrates. One surface of the substrate is bonded to an acoustically absorptive backing material. Either surface can be made to conform to a singly or doubly curved geometry. Electrodes deposited on these substrates may be continuous to form a single transducer element, or segmented to form sub-arrays of transducer elements.

Abstract: A power transfer system for converting recurring wave movement within the ocean to electrical energy. The system comprises pressure sensing structure such as a pressure transducer 10 or combination movable magnet and coil 50, positioned below water level and at a location 20 of wave movement for (i) registering changes in height of water 18 and 19 above the pressure sensing structure 10, 50 and (ii) providing electrical power output at the ocean floor corresponding to changes in gravity force associated with the changes in the height of water. A transfer medium 12 is coupled at one end to the pressure sensing structure and extends at a second end to a shore location. A power receiving device such as a bank of storage batteries 14 or electrical load is coupled to the transfer medium at the shore location for receiving the power output from the transfer medium and for processing the power for use.

Abstract: A three-dimensional array of acoustic sensors. The array can be used for both the transmission and reception of acoustic signals. The array comprises electroplated piezoelectric polymer layers that are laminated with a non-conductive epoxy to form individual multi-layer array transducer elements. Circuit support layer layers are incorporated between the multi-layer array transducer elements. Because of the three-dimensional configuration of the array, logical transducers can be created from multiple transducer elements, and transmission and reception of acoustic signals in any direction can be realized.

Abstract: A torsional motor, comprising: a plurality of segments in the shape of a tube comprising an electroactive material with a poling along the length dimension with adjacent segments arranged with their respective polings in opposed directions; a plurality of conductors between the adjacent segments; a first one-way clutch; a second one-way clutch; a first rotor positioned relative to the first one-way clutch such that the angular displacement of the tube in one direction is transmitted by the first one-way clutch to the first rotor; and a second rotor positioned relative to the second one-way clutch such that the angular displacement of the tube in one direction is transmitted by the second one-way clutch to the second rotor.

Abstract: A flextensional transducer projector shell design is disclosed. The shell design has a shape formed so as to reduce the stress placed on the transduction driver as compared to other shell designs. The shell design includes first and second bulbous end portions, which can each be adapted to receive a respective end of a transduction driver. A middle portion of the shell design has both concave sections and convex sections, thereby defining a wave profile.

Abstract: A process and apparatus for treating a wellbore, comprising subjecting a substantially same portion of the wellbore to vibratory waves produced by a plurality of vibratory wave generators. The vibratory waves may have about the same frequency or a plurality of frequencies, and the frequencies may partially overlap, not overlap, or be modulated across a range. Additionally, the frequencies may be modulated in an oval, hoop, and flexural modes. The vibratory waves may be produced by firing the vibratory wave generators simultaneously or in sequence. Combinations of a vibrating pipe, piston pulser, or valve may be used as vibratory wave generators. In a preferred embodiment, the thickness and change of thickness of a mudcake on the interior surface of a wellbore are measured to evaluate the effectiveness of the wellbore treatment.

Abstract: An underwater wide-band electroacoustic transducer and a method of packaging the transducer. The underwater wide-band electroacoustic transducer comprises of several groups of piezoelectric ceramic units and acoustic window material. To produce the underwater wide-band electroacoustic transducer, groups of piezoelectric ceramic units each having a different dimension are assembled such that each ceramic unit separates from each other by different distances. The frequency response of each ceramic unit groups are added together to provide a wide-band frequency response. The acoustic window material is injected to joins the ceramic unit groups together into a package.

Abstract: An underwater acoustic projector comprising a pair of spaced apart end walls with an acoustic driver positioned between the end walls, the driver having smaller cross-sectional dimensions than the end walls. The projector has a one piece thin wall inwardly concavely shaped shell with corrugations running in the axial direction surrounding the driver and mechanically coupled to the end walls. An open ended tubular waveguide (pipe) is connected to each end wall of the projector and extend outward forming a flextensional resonant pipe projector.

Abstract: An underwater acoustic projector comprising a pair of spaced apart end walls with an acoustic driver positioned between the end walls, the driver having smaller cross-sectional dimensions than the end walls. Each end wall close one end of flared open ended pipe waveguides and is mechanically coupled to one end of a piezoelectric acoustic driver. The flared pipe waveguides extend outward from the driver and have a larger diameter at their open ends than at the end walls.

Abstract: Provided is a pressure-balanced underwater acoustic transducer. The transducer includes an oscillator unit having an oscillator oscillating by an electrical signal supplied to electrodes, provided on its surface, a sound transmission material for transmitting sound from the oscillator, provided at its periphery, and a transducer housing provided at the exterior of the sound transmission material, a sound reflector positioned over the oscillator unit, for reflecting sound propagated from the oscillator, a water entry layer formed at a space between the oscillator unit and the sound reflector to allow water to enter and exit to the rear window of the oscillator, thereby leading to a balanced state of pressures applied to the front and rear windows of the oscillator, and a phase combiner for combining sound reflected from the sound reflector and straight traveling sound generated from the front window of the oscillator into one single phase.

Abstract: An underwater acoustic projector comprising a pair of spaced apart end walls with an acoustic driver positioned between the end walls, the driver having smaller cross-sectional dimensions than the end walls. Each end wall close one end of open ended tubular pipe waveguides and is mechanically coupled to one end of a piezoelectric acoustic driver.

Abstract: Provided is a pressure-balanced underwater acoustic transducer. The transducer includes an oscillator unit having an oscillator oscillating by an electrical signal supplied to electrodes, provided on its surface, a sound transmission material for transmitting sound from the oscillator, provided at its periphery, and a transducer housing provided at the exterior of the sound transmission material, a sound reflector positioned over the oscillator unit, for reflecting sound propagated from the oscillator, a water entry layer formed at a space between the oscillator unit and the sound reflector to allow water to enter and exit to the rear window of the oscillator, thereby leading to a balanced state of pressures applied to the front and rear windows of the oscillator, and a phase combiner for combining sound reflected from the sound reflector and straight traveling sound generated from the front window of the oscillator into one single phase.