Abstract: An ultrasonic transducer arraying at even intervals ultrasonic transducers for transmitting and receiving ultrasonic waves and layering a plurality of acoustic matching layers on them, comprising an transducer shape forming member made of a fiber-reinforced thermosetting PPE for filling a gap formed on the side face of the ultrasonic transducer with the same material as that of the acoustic matching layer, mixing a colorant in a division member adjacent to a predefined ultrasonic transducer from among a plurality of ultrasonic transducers, and arraying the plurality thereof.

Abstract: Provided is an organic piezoelectric material which has excellent piezoelectric property, heat resistance property in particular. An ultrasonic oscillator, which is to be used for an ultrasonic medical diagnostic imaging device which can receive high frequencies at high sensitivity and is suitable for harmonic imaging techniques, a method for manufacturing such oscillator, and an ultrasonic probe are also provided. The ultrasonic medical diagnostic imaging device is provided by sing such oscillator, method and probe. The organic piezoelectric material is characterized by containing empty particles having an average particle diameter of 10 ?m or less.

Abstract: A transducer with a closed heat pipe is provided with a hot surface and a cold surface. The hot surface is in contact with the transducer interior and the cold surface is in contact with a cooler contact area. A fluid is used in the pipe which boils at the temperature of the hot surface and condenses at the temperature of the cold surface. A wick inside the heat pipe facilities the return by capillary action of the condensed fluid to the hot end. The heat pipe can be evacuated to adjust the boiling temperature of the fluid. A variant involves drilling additional holes into ceramic rings and inserting heat pipes. Increasing the heat pipe length into the tail mass and the piston increases the cool region for the fluid to condense; thereby improving the performance of the transducer.

Abstract: A transducer for transmitting and receiving ultrasound waves and a method for constructing a transducer. The transducer having layers of a single crystal piezoelectric material stacked in a multilayer arrangement and a polymer material geometrically arranged within each layer to form a 3-1 connectivity piezoelectric and polymer composite. The multilayer arrangement includes at least two layers of different thickness. The structure allows the generation of odd and even harmonics to significantly increase bandwith without reducing signal amplitude or efficiency.

Abstract: A thin-film device and a method of fabricating the thin-film device are provided herein. The thin-film device comprises a bond layer, a film layer that has bulk material properties, and a substrate that has a heat-sensitive component disposed thereon. The method of fabricating the thin-film device comprises the step of providing an active material that has bulk material properties. The active material is bonded to the substrate through the bond layer. After bonding the active material to the substrate, the active material that is bonded to the substrate is thinned to produce the film layer of the thin-film device. The substrate is provided with the heat-sensitive component disposed thereon prior to bonding the active material to the substrate.

Abstract: A variance in transmitting/receiving sensitivity between multiple vibrational elements or transducers included in an ultrasonic probe is corrected. An ultrasonic probe in accordance with the present invention has multiple transducers, each of which includes multiple vibrational elements that each transmit or receive ultrasonic waves by converting ultrasonic waves and an electric signal into each other with a bias voltage applied thereto, set in array. The ultrasonic prove includes a transmitting/receiving sensitivity correction means that independently adjusts the bias voltage to be applied to at least two vibrational elements among the multiple vibrational elements so as to correct a variance in transmitting/receiving sensitivity between the at least two vibrational elements.

Abstract: The present invention refers to an ultrasonic device comprising an ultrasound transducer; and a disk-shaped metallic low-frequency ultrasound (NFLUS) resonator being mechanically connected with the ultrasound transducer on one side of the resonator; a container with an opening on its bottom side and being arranged on the other side of the disk-shaped resonator such that the opening is facing the disk-shaped resonator; an elastic sealing element arranged between the disk-shaped resonator and the container for sealing the container around the opening; and means for supplying a pressing force such that the container is tightened on the resonator during ultrasonication, but can be repeatedly disassembled and assembled after ultrasonication.

Abstract: Disclosed is an organic piezoelectric material which has particularly excellent heat resistance, while exhibiting excellent transparency, surface gloss, adhesion and piezoelectric characteristics. Also disclosed are an ultrasonic oscillator used in an ultrasonic medical diagnostic imaging device, which is capable of highly sensitively receiving a high frequency wave and suitable for harmonic imaging technique, a method for producing the ultrasonic oscillator, an ultrasonic probe, and an ultrasonic medical diagnostic imaging device. The organic piezoelectric material is characterized in that the piezoelectric material is formed by laminating two or more films at the same time by a coating process.

Abstract: A third matching layer (140) affording wide bandwidth for an ultrasound matrix probe is made of polyethylene, and may extend downwardly to surround the array (S360) and attach to the housing to seal the array (S370).

Abstract: A piezoelectric acoustic element 1 of the present invention comprising a hollow casing 5 having a opening 3, a piezoelectric element 7 that is disposed in said casing 5 and bends when a voltage is applied thereto, and diaphragm 8 provided at the opening 3 of said casing 5; wherein said piezoelectric element 7 and said diaphragm 8 are joined through a vibration transmitting member 9.

Abstract: A component working with guided bulk acoustic waves includes a first substrate, a second substrate, and a layer system between the first and second substrates. The layer system includes a metal layer and a dielectric layer. A ratio of the acoustic impedance of the metal layer to the acoustic impedance of the dielectric layer is greater than or equal to 4.5.

Abstract: An multi-channel array type ultrasound probe (search unit) disposed at least one-dimensionally, having: a plurality of sheet-shaped piezoelectric elements as transmission reception separation type complex piezoelectric element, wherein a material configuring a transmission piezoelectric element of the complex type piezoelectric element has an elastic coefficient of 10 Gpa to 100 Gpa at 23° C., and a material configuring a reception piezoelectric element of the complex type piezoelectric element has an elastic coefficient of 10 Gpa to 1 Gpa at 23° C.

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 ultrasonic probe suitable for reducing reflected waves returning from a rear surface part to a transducer side, and an ultrasonic diagnostic apparatus. Ultrasonic probe 1 comprises transducer 10 transmitting and receiving ultrasonic waves to and from a subject, a backing material 12 disposed on the rear side of the transducer 10, and heat dissipating block 14 stacked on the backside of the backing material 12. At least one of the backing material 12 and heat-dissipating block 14 comprises void 16 therein. A sound absorbing material 18 is desirably filled in void 16.

Abstract: An ultrasonic transducer comprises a stack having a first face, an opposed second face and a longitudinal axis extending therebetween. The stack comprises a plurality of layers, each layer having a top surface and an opposed bottom surface, wherein the plurality of layers of the stack comprises a piezoelectric layer and a dielectric layer. The dielectric layer is connected to the piezoelectric layer and defines an opening extending a second predetermined length in a direction substantially parallel to the axis of the stack. A plurality of first kerf slots are defined therein the stack, each first kerf slot extending a predetermined depth therein the stack and a first predetermined length in a direction substantially parallel to the axis.

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: 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: In one aspect, matching layers for an ultrasonic transducer stack having a matching layer comprising a matrix material loaded with a plurality of micron-sized and nano-sized particles. In another aspect, the matrix material is loaded with a plurality of heavy and light particles. In another aspect, an ultrasound transducer stack comprises a piezoelectric layer and at least one matching layer. In one aspect, the matching layer comprises a composite material comprising a matrix material loaded with a plurality of micron-sized and nano-sized particles. In a further aspect, the composite material can also comprise a matrix material loaded with a plurality of heavy and light particles. In a further aspect, a matching layer can also comprise cyanoacrylate.

Abstract: Improved acoustic attenuation materials and applications are provided. An improved acoustic attenuation material may include a woven layer of fibers made of porous polymers, such as porous polytetrafluoroethylene (PTFE), that include interstitial space. An improved acoustic attenuation material may include sheets of porous polymers interleaved with layers of epoxy. The sheets of porous polymers may include through holes. An embodiment of an ultrasonic transducer that includes a backing with woven layers of porous PTFE fibers is provided. The ultrasonic transducer that includes a backing with woven layers of porous PTFE fibers may be used in a three-dimensional ultrasound imaging apparatus. An embodiment of an ultrasonic transducer that includes a plurality of sheets of porous PTFE interleaved with layers of epoxy is provided. The ultrasonic transducer that includes a plurality of sheets of porous PTFE may be used in an ultrasonic imaging catheter.

Abstract: Systems and methods which improve the directivity of a transducer array by reducing electrical cross-talk between conductors connected to individual transducer array elements through the use of a plurality of interconnect circuits are shown. A plurality of signal transmission path circuits, such as circuit boards, flexible printed circuits, etc., are used to provide electrical power to and receive signals from transducer elements of a transducer array. Embodiments couple transducer elements to conductive traces of the signal transmission path circuits in a manner such that adjacent transducer elements are not connected to conductive traces on the same signal transmission path circuit. In some embodiments, a plurality of signal transmission path circuits are offset such that two identical signal transmission path circuits can be used to provide connectivity to array transducer elements using more widely spaced conductive traces, thus reducing electrical cross-talk effects.

Abstract: Provided herein are composite passive layers for ultrasound transducers having acoustic properties that can be easily tailored to the needs of the transducer application using current microfabrication techniques. In an embodiment, a passive layer comprises metal posts embedded in a polymer matrix or other material. The acoustic properties of the passive layer depend on the metal/polymer volume fraction of the passive layer, which can be easily controlled using current microfabrication techniques, e.g., integrated circuit (IC) fabrication techniques. Further, the embedded metal posts provide electrical conduction through the passive layer allowing electrical connections to be made to an active element, e.g., piezoelectric element, of the transducer through the passive layer. Because the embedded metal posts conduct along one line of direction, they can be used to provide separate electrical connections to different active elements in a transducer array through the passive layer.

Abstract: In an embodiment, an apparatus and method capable of determining the time and location of a projectile's impact is disclosed. In another embodiment, an apparatus and method capable of determining the time and location of a projectile's impact as well as the direction from whence the projectile came is disclosed.

Abstract: A method for forming an acoustical stack for an ultrasound probe comprises partly dicing a single crystal piezoelectric material to form single crystal pieces that are partly separated by a plurality of kerfs. The single crystal piezoelectric material comprises a carrier layer. The kerfs are filled with a kerf filling material to form a single crystal composite and the carrier layer is removed. At least one matching layer is attached to the single crystal composite, and dicing within the kerfs is accomplished to form separate acoustical stacks from the single crystal composite.

Abstract: An acoustical stack for an ultrasound probe comprises a piezoelectric layer having top and bottom sides and a plurality of matching layer sections forming a matching layer structure. Each of the matching layer sections comprises a spring layer comprising a first material and a mass layer comprising a second material that is different than the first material. The spring layer within the matching layer section that is positioned closest to the piezoelectric layer is thinner than the spring layer within the other matching layer sections.

Abstract: An anti-EMI ultrasonic transducer has a conductive casing, a piezoelectric ceramic board having an opening, a conductive shelter, a first and second wires and an encapsulation. A first electrode face of the piezoelectric ceramic board faces to the opening and a second electrode face is mounted inside the conductive casing. The conductive shelter is mounted inside the conductive casing or covered to the opening, so the piezoelectric ceramic board is encapsulated in the conductive shelter and the conductive casing. Since the second signal wire is connected to the conductive shelter mounted inside the conductive casing, the conductive shelter and the conductive casing and the second electrode face of the piezoelectric ceramic board are commonly electronically connected to a voltage signal transmitted by the second signal wire. Therefore, the conductive shelter and the conductive casing are constituted to an EMI shelter for the piezoelectric ceramic board to resist external EMI signal.

Abstract: An ice re-surfacing machine an acoustically isolated face shield around the intake mouth of its vertical conveyor housing. Ultrasonic vibrations induced in the shield prevent build-up of ice from cuttings thrown at the mouth by the machine's horizontal conveyor.

Abstract: In an ultrasonic probe in which individual wires led out from multilayered piezoelectric elements are arranged in a staggered manner, short-circuit is prevented. Each of the elements includes: a multilayered structure in which piezoelectric material layers and at least one internal electrode are stacked; first and second flat electrodes; first and second side electrodes; an insulating film formed at a second side surface side of the multilayered structure; a wiring member bonded to the first flat electrode on the one end of the multilayered structure by using a conducting adhesive material; and the wiring member is provided at the second side surface side of the multilayered structure and the insulating film electrically separates the second side electrode and the conducting adhesive material in a first element, and the wiring member is provided at a first side surface side of the multilayered structure in a second element.

Abstract: Transducer assemblies and methods of replacing having a housing, a removable diaphragm, and a sealing diaphragm. The transducer assembly may be used with a spool piece to prevent fluid from escaping from the spool piece when parts of the transducer assembly are removed.

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: An ultrasonic sensor includes a cylindrical case with a bottom. A piezoelectric element is bonded to an inner side of a bottom portion of the case, and a felt is bonded to the piezoelectric element. A cap is fitted to an opening of the case. The cap includes a fixing portion and a substrate which is harder than the fixing portion. Terminals are press-fitted to the substrate. Wires are connected to the terminals, so that the terminals are electrically connected to the piezoelectric element. A through hole is provided in the fixing portion. Resin before being foamed is injected from the through hole and then foamed, so that the case is filled with foamable resin while an excess amount of foamable resin is pushed out from the through hole.

Abstract: An ultrasound transducer includes one or more microbeamformer integrated circuit chips, an array of acoustic elements, and a redistribution interconnect coupled via conductive elements between the one or more integrated circuit chips and the array of acoustic elements. The one or more microbeamformer integrated circuit chips each include a plurality of bond pads separated from adjacent ones thereof by a first pitch set. The acoustic elements of the array are separated from adjacent ones thereof by a second pitch set, the second pitch set being different from the first pitch set. In addition, the redistribution interconnect couples on a first side of the redistribution interconnect to the one or more microbeamformer integrated circuit chips via conductive elements. The redistribution interconnect couples on a second side to the array of transducer elements via conductive elements.

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: An ultrasonic imaging system wherein an exemplary system includes an array of transducer elements arranged along a first plane for transmitting first signals and receiving reflected signals for image processing. Circuit structures each have a major surface positioned in a co-planar orientation with respect to a major surface of another of the circuit structures to provide a sequence of the structures in a stack-like formation. Electrical connections are formed between adjacent circuit structures in the sequence. A connector region on each circuit structure includes a distal portion extending away from the major surface-with distal portions of connector regions of adjacent structures spaced apart from one another. A first wiring pattern extends from the major surface to the distal portion of the connector region.

Abstract: An apparatus includes a first bulk acoustic wave (BAW) device including a first impedance and a second BAW device including a second impedance, wherein the first and second impedances are different and the first and second BAW devices are acoustically coupled.

Abstract: The invention proposes a process for the surface treatment of aluminium in order to produce an electrical contact, and a corresponding component part, wherein an oxide layer on the aluminium surface is removed, for example by etching, in a first step and, in a second step, before an oxide layer is re-formed, the surface is sealed wet-chemically with a conversion layer having metal ions of zirconium or titanium.

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: 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: Presented is a method of operating a capacitive microfabricated ultrasonic transducer (cMUT) array with multiple firings of varying bias voltage polarity patterns to improve its performance in imaging non-linear media, such as in contrast agent imaging or tissue harmonic imaging. Additionally, transducers incorporating the method are provided. The method of cMUT operation and the corresponding cMUT does not require pre-distortion or phase inversion of the transmit signal and can achieve an improvement in the elevation focus of the cMUT, as compared to the elevation focus that a single firing can achieve. Further, the method of operating the cMUT minimizes the deleterious effects that result from insulators being subjected to high electric fields.

Abstract: Disclosed is an electronic component bonding method which interposes a bonding resin between first and second electronic components to bond the first and second electronic components to each other. The electronic component bonding method includes providing the bonding resin between the first and second electronic components, aligning the first and second electronic components with each other, pre-curing the bonding resin to generate elasticity in the bonding resin, performing a main curing operation to apply vibration energy to the bonding resin, which has elasticity according to pre-curing, to securely fix the first and second electronic component to each other, and control the amplitude of the vibration energy applied during the main curing operation to be restricted within an elastic region of the bonding resin.

Abstract: An acoustic transducer assembly comprises a bipolar transducer (1) having an active surface with opposite ends that move towards and away from one another in response to an applied electrical fields. An acoustic decoupling material (2) is fixed to one end of the transducer surface, the acoustic decoupling material being such that it substantially prevents acoustic signals passing therethrough and substantially prevents coupling of the transducer's active surface.

Abstract: A mechanically formed transducer capable of producing a non-ideal focal region is described. The transducer has a plurality of piezoelectric elements suspended in an epoxy and heat molded into a desired shape. One or more shaped irregularities in the transducer provides for a mechanically induced non-ideal focal field without the need for electronic steering or lens focusing. Systems and methods of making the same are also described.

Abstract: An intravascular ultrasonic imaging catheter is provided with a flexible circuit electrically coupled to a transducer array mounted on the distal end of the catheter, a portion of the flexible circuit being helically wound about the catheter in order to enhance the flexibility of the circuit. The catheter may be a balloon catheter which is also provided with a stent mounted on the balloon, the stent carrying one or more drugs designed to be eluted or washed into a patient's blood stream after the stent has been delivered, by a the balloon catheter, into a target area within the patient's vascular system.

Abstract: A system for transporting particles includes a substrate and a plurality of spaced electrically conductive electrodes carried by the substrate. Further included is a carrier medium adapted for the retention and migration of particles disposed therein, wherein the carrier medium is in operational contact with the electrodes, and a vibration generator is positioned in relation to the substrate to impart vibrations into the carrier medium. In an alternative embodiment, the vibration generator is configured to generate an acoustic traveling wave, which includes a vibration component and a motivation component.

Abstract: A piezoelectric actuator is disclosed. The piezoelectric actuator includes a base member and three or more piezoelectric element members in which plural piezoelectric elements are formed by slits. The three or more piezoelectric element members are arrayed in a line on the base member and a gap is formed at the connection position between two adjacent piezoelectric element members.

Abstract: An air-coupled transducer includes a ultrasonic transducer body having a radiation end with a backing fixture at the radiation end. There is a flexible backplate conformingly fit to the backing fixture and a thin membrane (preferably a metallized polymer) conformingly fit to the flexible backplate. In one embodiment, the backing fixture is spherically curved and the flexible backplate is spherically curved. The flexible backplate is preferably patterned with pits or depressions.

Abstract: A probe for an ultrasonic diagnostic apparatus and a method of manufacturing the same are disclosed. The probe includes a backing layer having a first electrode part, a piezoelectric member connected to the first electrode part, a sound matching layer having a second electrode part connected to the piezoelectric member, and a PCB connected to the first and second electrode parts. The probe is configured to allow easy and rapid connection between the piezoelectric member and the PCB while providing improved durability and uniformity to a connected part between the piezoelectric member and the PCB, thereby enabling easy and rapid manufacture of the probe while preventing deterioration in performance caused by defective connection between the piezoelectric member and the PCB.

Abstract: A technique that can make a heat radiation effect higher and makes even a transmission voltage of an ultrasonic diagnostic apparatus higher and then makes a diagnostic depth deeper is disclosed.

Abstract: An ultrasonic probe including a piezoelectric vibrator configured to transmit and receive ultrasonic waves, an acoustic lens configured to focus the ultrasonic waves and an acoustic matching layer arranged between the piezoelectric vibrator and the acoustic lens and configured to modify acoustic impedance from the piezoelectric vibrator to the acoustic lens. The acoustic matching layer includes a first region arranged at center areas along a direction of transmitting and receiving of the ultrasonic waves, a second region arranged between the first region and the piezoelectric vibrator and having a rate of change of acoustic impedance which is less than rate of change of acoustic impedance of the first region and a third region arranged between the first region and the acoustic lens, and having a rate of change of acoustic impedance which is less than a rate of change of acoustic impedance of the first region.

Abstract: In one aspect, matching layers for an ultrasonic transducer stack having a matching layer comprising a matrix material loaded with a plurality of micron-sized and nano-sized particles. In another aspect, the matrix material is loaded with a plurality of heavy and light particles. In another aspect, an ultrasound transducer stack comprises a piezoelectric layer and at least one matching layer. In one aspect, the matching layer comprises a composite material comprising a matrix material loaded with a plurality of micron-sized and nano-sized particles. In a further aspect, the composite material can also comprise a matrix material loaded with a plurality of heavy and light particles. In a further aspect, a matching layer can also comprise cyanoacrylate.

Abstract: An ultrasound transducer array having a transmit transducer element comprising a transmit transducer material interposed between a transmit electrode and a reference electrode, wherein voltages applied across the transmit electrode and reference electrode induce an acoustic wave to emanate from the transmit transducer material; and a plurality of receive transducer elements positioned in an array on the transmit transducer element, each of the plurality of the receive transducer elements comprising a receive electrode and a receive transducer material interposed between the receive electrode and the reference electrode, and wherein acoustic waves applied to the plurality of receive transducer elements induces receive voltage signals on the receive electrodes with respect to the reference electrode.