Abstract: Embodiments relate to noncontact determination of nonlinearities. Initially, a first and second primary signal are preconditioned to produce a first and second tone capable of reaching a target granular media. Using a sound source, the first and second primary signals are emitted such that the first and second primary signals combine in a nonlinear fashion in the target granular media to produce low frequency acoustic tone that is a difference between the first and primary signals. An acoustic pulse is received by an acoustic receiver, and a quadratic nonlinearity coefficient and an acoustic pressure field are determined based on the acoustic pulse. At this stage, a sediment shear strength of the granular media is correlated to the quadratic nonlinearity coefficient to generate a shear strength lookup table.

Abstract: The invention concerns an underwater vehicle equipped with electrochemical means of electrical power generation, characterized in that it comprises a data processing unit (2) with inputs connected to sensors (4) of a parameter selected from amongst temperature, pressure, and hydrogen concentration, of the water in the area of the vehicle, and of the electrochemical means of the vehicle, and with outputs connected to means (5) of transmitting signals to transmit signals authorizing (or not authorizing) an operator to approach the vehicle, depending on whether the sensed value of the parameter of the electrochemical means is in a predetermined range around the value of the parameter corresponding to water in the area of the underwater vehicle.

Abstract: An ultrasonic transmitting unit includes a first vibrating section and a second vibrating section vibrating at the same predetermined frequency with respect to each other. The ultrasonic transmitting unit includes a relay portion transmitting an ultrasonic vibration from the first vibrating section to the second vibrating section and positioned at a position corresponding to one of an antinode position of the vibration in the first vibrating section and a position different from an antinode position and a node position of the vibration in the second vibrating section, and a non-contact vibrating portion extending in the second vibrating section from the relay portion toward a first vibrating section side with being not in contact with the first vibrating section.

Abstract: Disclosed are methods and systems for using a rigid-stem assembly comprising a plurality of interconnected rigid stems in a marine survey. An embodiment discloses a geophysical sensor streamer comprising a rigid-stem assembly comprising a plurality of rigid stems that are interconnected and each comprise a stem body defining one or more interior chambers, wherein a geophysical sensor is incorporated into one or more of the rigid stems.

Abstract: An oscillation device includes: a piezoelectric vibrator (110) in which electrode layers (112, 113) are formed over top and bottom surfaces of a piezoelectric layer (111); a vibrating member (120) having at least atop surface to which the piezoelectric vibrator (110) is bonded; and a resin member (130) formed continuously in a circumferential direction over at least the outer side surface of the piezoelectric vibrator (110). Therefore, since it is possible to increase the working area of the piezoelectric vibrator, it is possible to realize both an increase in the sound pressure level of the output and miniaturization of the apparatus.

Abstract: A multi-tank indirect liquid level measurement device and method are disclosed. The device and method may be implemented using a sealable reservoir that holds an indicating liquid and pressurized air, a pump that supplies and/or pressurizes the air in the reservoir, a plurality of pipes each of which connect on one end to the tanks to be gaged and on their other ends to a valve for selectively and exclusively connecting to the pressurized air, and a manometer tube that displays the pressure difference between the sealable reservoir and atmospheric pressure as a height reading of the indicating liquid.

Abstract: An ultrasound backing element, a transducer including the ultrasound backing element, and an ultrasound probe. The ultrasound backing element includes: a first concave/convex unit formed of a material capable of absorbing ultrasonic waves, and comprising a first surface and a second surface that are not in parallel with each other; and a first electrode unit comprising a first electrode and a second electrode that are respectively disposed on the first surface and the second surface.

Abstract: Ultrasonic signals are used to transmit sounds from a modulated ultrasonic generator to other locations from which the sounds appear to emanate. In particular, an ultrasonic carrier is modulated with an audio signal and demodulated on passage through the atmosphere. The carrier frequencies are substantially higher than those of prior systems, e.g., at least 60 kHz, and the modulation products thus have frequencies which are well above the audible range of humans; as a result, these signals are likely harmless to individuals who are within the ultrasonic fields of the system. The signals may be steered to moving locations, and various measures are taken to minimize distortion and maximize efficiency.

Abstract: An ultrasonic transducer for determining and/or monitoring flow of a measured medium through a measuring tube, which includes at least one piezoelectric element, at least one coupling element and at least one adapting, or matching, layer between the piezoelectric element and coupling element. The adapting, or matching, layer has a thickness smaller than a fourth of an uneven integer multiple of a wavelength of an ultrasonic signal being used.

Abstract: An ultrasonic sensor includes a transmitting device, a receiving device, and a circuit device. The circuit device determines that the receiving device receives an ultrasonic wave reflected from an object, when an output voltage of the receiving device is equal to or greater than a first threshold. The circuit device includes a humidity detection section configured to detect an ambient humidity of the transmitting and receiving devices and a threshold adjustment section configured to calculate, based on the detected ambient humidity, a sound pressure of the ultrasonic wave that is received by the receiving device after propagating over a round-trip distance between the ultrasonic sensor and the object. The threshold adjustment section reduces the first threshold, when the output voltage corresponding to the calculated sound pressure is less than a second threshold that is greater the first threshold.

Abstract: A water pillow for coupling acoustic energy into tissue. The pillow is configured to conform to a transducer to facilitate coupling of ultrasound energy. The pillow includes a pouch that accommodates the transducer to enable a snug fit between the pillow and the transducer. The pillow includes a liquid inlet and outlet to facilitate liquid circulation for cooling, is biocompatible, has a low attenuation, is conformal to the shape of the transducer, facilitates use of an adjustable pressure to achieve various standoffs, includes an integral pouch to facilitate an interference fit to the transducer, facilitates water circulation for cooling, is sterilizable, and is disposable. Either the surface of the pillow adapted to conform to a tissue interface, or the surface of the pillow adapted to conform to the transducer, or both, can include pores configured to weep liquid to facilitate acoustic coupling of the pillow with the transducer and/or tissue.

Abstract: An ultrasonic transducer having a reduced cost of manufacture. The ultrasonic transducer includes a first insulative retaining layer, a second insulative retaining layer, and a vibrator film layer sandwiched between the first and second retaining layers. The first retaining layer includes a first plurality of apertures formed therethrough, and the second retaining layer includes a second plurality of apertures formed therethrough, in which the second apertures are substantially in registration with the first apertures. The ultrasonic transducer further includes a first cover portion having a plurality of spring/backplate assemblies connected thereto, and a second cover portion. The combination of the first retaining layer, the vibrator film layer, and the second retaining layer is sandwiched between the first and second cover portions of the ultrasonic transducer.

Abstract: An ultrasonic transducer having a reduced cost of manufacture. The ultrasonic transducer includes a first insulative retaining layer, a second insulative retaining layer, and a vibrator film layer sandwiched between the first and second retaining layers. The first retaining layer includes a first plurality of apertures formed therethrough, and the second retaining layer includes a second plurality of apertures formed therethrough, in which the second apertures are substantially in registration with the first apertures. The ultrasonic transducer further includes a first cover portion having a plurality of spring/backplate assemblies connected thereto, and a second cover portion. The combination of the first retaining layer, the vibrator film layer, and the second retaining layer is sandwiched between the first and second cover portions of the ultrasonic transducer.

Abstract: An acoustic matching member is fitted to a main body in a pair of ultrasonic transmitter/receivers. The acoustic matching member includes a matching member equipped with a porous body adhered tightly to an acoustic-wave emission surface of the main body. A dense layer is stacked on a surface of the porous body and includes a thermosetting resin and first flowability-diminishing particles. A sidewall member is adhered tightly to the acoustic-wave emission surface and an end face of the porous body.

Abstract: An ultrasonic sensor includes a transmitting device, receiving devices arranged in an array, and a circuit device. One receiving device is configured as a reference receiving device. The circuit device includes a reference signal generator and first and second synchronous detectors. The reference signal generator generates a reference signal by using a received signal of the reference receiving device. The first synchronous detector performs synchronous detection of a received signal of one of the receiving devices based on the reference signal to detect a distance to an object. The second synchronous detector performs synchronous detection of received signals of the receiving devices except the reference receiving device based on the reference signal to detect a direction of the object.

Abstract: An ultrasonic sensor includes a transmitting device, receiving devices arranged in an array, and a circuit device. One receiving device is configured as a reference receiving device. The circuit device includes a reference signal generator and first and second synchronous detectors. The reference signal generator generates a reference signal by using a received signal of the reference receiving device. The first synchronous detector performs synchronous detection of a received signal of one of the receiving devices based on the reference signal to detect a distance to an object. The second synchronous detector performs synchronous detection of received signals of the receiving devices except the reference receiving device based on the reference signal to detect a direction of the object.

Abstract: An acoustic matching member, an ultrasonic transmitter/receiver, and an ultrasonic flowmeter, which are capable of measuring a flow rate of a fluid with greater accuracy, are provided. An acoustic matching member 24 is fitted to a main body 21 in a pair of ultrasonic transmitter/receivers 15, 16. The acoustic matching member 24 includes a matching member 34 equipped with a porous body 35 adhered tightly to an acoustic-wave emission surface 27 of the main body 21, and a dense layer 37 stacked on a surface 35B of the porous body 35 and including a thermosetting resin 38 and first flowability-diminishing particles 39, and a sidewall member 36 adhered tightly to the acoustic-wave emission surface 27 and an end face 35A of the porous body 35.

Abstract: This disclosure provides a detection device, which includes a transceiving module for periodically transmitting a detection pulse signal toward a space and receiving a reflection wave from a target object as a reception signal, a signal loading module for generating a distance section row by dividing a given detection distance range into a plurality of distance sections, obtaining reception data by sequentially sampling the reception signal for every distance section, and storing the reception signal in a memory, and an interference processing module for sequentially performing interference removal processing for the reception data of each of the distance sections stored in the memory.

Abstract: An ultrasonic transducer having a reduced cost of manufacture. The ultrasonic transducer includes a first insulative retaining layer, a second insulative retaining layer, and a vibrator film layer sandwiched between the first and second retaining layers. The first retaining layer includes a first plurality of apertures formed therethrough, and the second retaining layer includes a second plurality of apertures formed therethrough, in which the second apertures are substantially in registration with the first apertures. The ultrasonic transducer further includes a first cover portion having a plurality of spring/backplate assemblies connected thereto, and a second cover portion. The combination of the first retaining layer, the vibrator film layer, and the second retaining layer is sandwiched between the first and second cover portions of the ultrasonic transducer.

Abstract: A transducer assembly for downhole imaging includes a 1-3 Piezoelectric composite transducer of high Q ceramic rods in a polymer matrix. The assembly also includes a Teflon® window, a fluid-filled cavity adjacent to the window, and impedance matching material between the composite transducer and the fluid. The transducer is positioned to reduce the reverberation time.

Abstract: An ultrasonic sensor attached to a certain object, includes an ultrasonic detecting element, an acoustic matching member, and a reflection limiting member. The ultrasonic detecting element detects an ultrasonic wave. The acoustic matching member has a receiving surface that is adapted on a side of the certain object to face toward the detected body. The reflection limiting member is disposed to a side portion of the acoustic matching member between the receiving surface and an opposing surface of the acoustic matching member. The reflection limiting member limits the ultrasonic wave, which transmits inside the acoustic matching member, from being reflected by the side portion.

Abstract: In one embodiment the invention comprises a particle velocity sensor that includes a housing with a geophone mounted in the housing. A fluid that substantially surrounds the geophone is included within the housing. The particle velocity sensor has an acoustic impedance within the range of about 750,000 Newton seconds per cubic meter (Ns/m3) to about 3,000,000 Newton seconds per cubic meter (Ns/m3). In another embodiment the invention comprises method of geophysical exploration in which a seismic signal is generated in a body of water and detected with a plurality of co-located particle velocity sensors and pressure gradient sensors positioned within a seismic cable. The output signal of either or both of the particle velocity sensors or the pressure gradient sensors is modified to substantially equalize the output signals from the particle velocity sensors and the pressure gradient sensors. The output signals from particle velocity sensors and pressure gradient sensors are then combined.

Abstract: A predictor allows the computation of the greatest lower bound of the noise figure pertaining uniformly over the operating band of a wideband amplifier. This computation is done directly from noise-parameter data of the amplifier.

Abstract: The invention relates to an ultrasound transducer in particular for application in ultrasound anemometry, comprising an electromechanical transducer (1) with an acoustically active surface, an acoustic matching layer (3) arranged between the acoustic surfaces of the converter and the exposed acoustic surfaces, and an electrical heating element (2). The heating element (2) is arranged between the acoustically active surfaces of the transducer (1) and the matching layer (3).

Abstract: An acoustic transducer system for acoustic signals in water has at least one hollow spherically-shaped shell for vibrating in response to acoustic signals impinging from the water. The hollow spherically-shaped shell has one or more portions that are reflective of impinging radiation, and a resilient matrix in contact with the water resiliently supports the responsive hollow shell. A laser Doppler velocimeter transmits radiation onto the reflective portion (portions) and receives reflected radiation from the reflective portion (portions). The reflected radiation generates signals in the laser Doppler velocimeter that are representative of the acoustic signals from the water medium. A computer receives the representative signals from the laser Doppler velocimeter and displays them on an interconnected display to determine direction and range to a target. The acoustic signals can originate from the target or can be reflected portions of acoustic energy transmitted from an acoustic projector.

Abstract: A predictor for optimal transducer power gain computes the maximum transducer power gain attainable by a lossless matching network for a given load operating over selected non-overlapping (disjoint) sub-bands within a frequency band of operation.

Abstract: The invention, in its several embodiments, includes a method of making a plurality of impedance-matched layers interposed between an acoustical source and a target media providing optimal transmission of energy from the acoustical source to the target media.

Abstract: An improved acoustic window for an acoustic waveform passage having a generally uniform transmission loss at an angle of incidence of between −40° and +40°. The composition is formed from at least one core layer and at least two septa, with the core layer being a material having a generally low-acoustic-impedance, a static shear modulus between about 1.0 psi (0.007 MPa) and about 15,000 psi (103 MPa), a transverse (or through-thickness) sound velocity for the acoustic waveform of between about 700 and about 2200 meters per second, a transverse acoustic impedance of less than or equal to 4×106 kilograms per square meter-second, and a shear loss factor of greater than 0.02, the septa being composed of at least one ply of a material, preferably a graphite fiber reinforced epoxy composition, having a transverse acoustic impedance of less than 60×106 kg/m2-sec, a tensile modulus of more than 0.5×106 psi, a thickness of less than 0.

Abstract: The invention, in its several embodiments, includes a method of making a plurality of impedance-matched layers interposes between an acoustical source and a target media providing optimal transmission of energy from the acoustical source to the target media.

Abstract: An acoustic matching member that is incorporated into an ultrasonic transducer for transmitting and receiving ultrasonic waves, includes: at least two layers including a first layer and a second layer that have different acoustic impedance values from each other. The first layer is made of a composite material of a porous member and a filing material supported by void portions of the porous member, the second layer is made of the filling material or the porous member, and the first layer and the second layer are present in this stated order. A piezoelectric member is disposed on a side of the first layer of the acoustic matching member to form an ultrasonic transducer or an ultrasonic flowmeter. The acoustic matching member does not have independent intermediate layers between the layers, so that delamination hardly occurs and the difficulty in the designing associated with the presence of intermediate layers can be avoided.

Abstract: It is an object of the present invention to provide an ultrasonic transducer, which is so configured as to reduce the variations in characteristics, thereby to enable the stabilization of the precision, as well as to enable the improvement of the durability, and the like, a method for manufacturing the ultrasonic transducer, and an ultrasonic flowmeter. In order to attain this object, in accordance with the present invention, the ultrasonic transducer is so configured as to include a piezoelectric element and an acoustic matching layer, wherein the acoustic matching layer is made of a dry gel of an inorganic oxide or an organic polymer, and a solid skeletal part of the dry gel has been rendered hydrophobic. With this configuration, it is possible to obtain the ultrasonic transducer having an acoustic matching layer 3 which is very lightweight and has a small acoustic impedance due to the solid skeletal part of the dry gel which has been rendered hydrophobic.

Abstract: A method for maximizing the radiated power of a transducer, such as a sonar transducer, includes providing a transducer system comprising a transducer operating at a frequency f and having a radiating face, a tuning fluid having a density &rgr;1 and a speed of sound c1, a tuning plate having a density &rgr;p and a thickness t, and an external fluid having a density &rgr;2 and a speed of sound c2; and tuning the transducer to have a maximum specific acoustic resistance at the radiating face in accordance with the equation: [ ( 2 ⁢   ⁢ π ⁢   ⁢ f ⁢   ⁢ ρ p

Abstract: An acoustic matching member that is incorporated into an ultrasonic transducer for transmitting and receiving ultrasonic waves, includes: at least two layers including a first layer and a second layer that have different acoustic impedance values from each other. The first layer is made of a composite material of a porous member and a filling material supported by void portions of the porous member, the second layer is made of the filling material or the porous member, and the first layer and the second layer are present in this stated order. A piezoelectric member is disposed on a side of the first layer of the acoustic matching member to form an ultrasonic transducer or an ultrasonic flowmeter. The acoustic matching member does not have independent intermediate layers between the layers, so that delamination hardly occurs and the difficulty in the designing associated with the presence of intermediate layers can be avoided.

Abstract: A predictor for optimal broadband impedance matching of the present invention computes the maximum value of transducer power gain possible for any impedance matching network for a given transmission line, load, and frequency band.

Abstract: An acoustic matching member 1 is used, when a sound is propagated from a first object to a second object, for matching an acoustic impedance of the first object and an acoustic impedance of the second object. The acoustic matching member 1 includes a plurality of fine pieces 2, and at least one of the plurality of fine pieces 2 is bonded with at least another of the plurality of fine pieces at a contact portion so as to form a gap in the acoustic matching member 1.

Abstract: An acoustic impedance-matching transformer includes a tapered acoustic energy transmission (metal) block, having an acoustic impedance less than that of a piezo-electric transducer in a metric direction toward that of the acoustic propagation medium of the waveguide, and by an amount that allows tailoring of the relative spatial dimensions of mating surfaces of the transducer and the block, so as to provide efficient broadband coupling of acoustic energy. The surface area of the end face of the block engaging the transducer is a corresponding fraction of the area of the transducer. The tapered block focuses acoustic energy toward the input aperture of the waveguide channel. The taper is determined in accordance with difference between the acoustic impedance of the aluminum block and that of a second acoustic wave propagation element, such as a quarter-wave section of plexiglass, interposed between the waveguide channel and the tapered block.

Abstract: An ultrasonic probe includes a piezoelectric element for transmitting and receiving ultrasonic waves and an acoustic lens provided on an ultrasonic transmission/reception side of the piezoelectric element. The acoustic lens is formed in an acoustic lens shape by vulcanization formation through addition of 2,5-dimethyl-2,5-di-t-butyl peroxy hexane as a vulcanizing agent to a composition prepared by addition of silica (SiO2) particles in an amount of 40 wt % to 50 wt % to silicone rubber with a dimethylpolysiloxane structure including vinyl groups. Thus, the ultrasonic transmission and reception sensitivity is improved and the degradation in frequency characteristics is diminished. Consequently, higher resolution of an ultrasonic image and higher sensitivity can be achieved.

Abstract: An ultrasonic waveguide for guiding an ultrasonic signal situated in a predetermined frequency range is illustrated and described. The ultrasonic waveguide according to the invention is characterized in that it has a coiled foil whose layer thickness is considerably less than the smallest wavelength of the ultrasonic signal in the predetermined frequency range in the foil material. The result is that ultrasonic signal interference and attenuation in the ultrasonic waveguide due to scattering and dispersion are largely avoided.

Abstract: An acoustic impedance-matching transformer includes a tapered acoustic energy transmission (metal) block, having an acoustic impedance less than that of a piezo-electric transducer in a metric direction toward that of the acoustic propagation medium of the waveguide, and by an amount that allows tailoring of the relative spatial dimensions of mating surfaces of the transducer and the block, so as to provide efficient broadband coupling of acoustic energy. The surface area of the end face of the block engaging the transducer is a corresponding fraction of the area of the transducer. The tapered block focuses acoustic energy toward the input aperture of the waveguide channel. The taper is determined in accordance with difference between the acoustic impedance of the aluminum block and that of a second acoustic wave propagation element, such as a quarter-wave section of plexiglass, interposed between the waveguide channel and the tapered block.

Abstract: The invention relates to a piezoelectric transducer particularly for use in transit time measurements. The object of the invention is to provide a piezoelectric transducer which ensures an in-phase two-dimensional pulse emission which, independent of the selection of a definite excitation frequency, substantially closely follows the electric excitation at a low time deformation of the pulse owing to transient and dying-out operations and which permits to obtain sufficiently high sound levels at low amplitudes of the excitation voltage.

Abstract: Flextensional acoustic source with sound-emitting surfaces (1, 2, 3, 4) adapted to be excited into vibrational movement, and for use in seismic exploration at sea. The source comprises a drive unit (21) being through the intermediary of at least one push element (22A, 22B) adapted to impose vibrational movement to the sound-emitting surfaces. Between at least one push element (22A, 22B) and the associated sound-emitting surface(s) (1, 2, 3, 4) there is provided a non-linear spring element (27, 28) the spring constant of which is controllable. Two oppositely acting push elements (22A, 22B) are arranged in axial alignment and preferably centrally in the source, and in addition thereto there are provided at least two tension elements (39, 40) with associated controllable, non-linear spring elements (35, 36, 37, 38) and being coupled to the sound-emitting surfaces (1, 2, 3, 4).

Abstract: The invention relates to multifrequency acoustic transducers exhibiting a wide band around each resonant frequency. It consists in inserting between a .lambda./2 active emitter plate (201) and the soft reflector (203) which supports it a rear plate (202) resonating in .lambda./4 mode and in placing on this active plate two marcher plates (204, 205) whose impedances are designed so as to best match the two frequencies obtained by inserting this rear plate. Thicknesses of these marcher plates are optimized with the aid of a model of for example Mason type starting from a value close to .lambda./4 for the frequency to be matched. It makes is possible to construct sonar transducers which operate equally well in detection mode and in classification mode.

Abstract: This ultrasonic transducer has a high chemical resistance and a small diameter and can be used over a very wide temperature range. It has a single-piece, can-shaped housing (1) sealed off by a diaphragm (12), a sensor element (2), arranged in the housing (1), for transmitting and receiving ultrasound, a matching layer (3) arranged between the diaphragm (12) and the sensor element (2), a stress equalizing layer (5) which completely encloses the sensor element (2) apart from a front area adjoining the matching layer (3) and is made of a thermosetting plastic, especially of an epoxy resin, a clamping ring (4) coaxially enclosing the matching layer (3), and a damping layer (6) that fills a cavity that remains in the housing (1) and is bounded by the clamping ring (4), the stress equalizing layer (5) and the housing (1).

Abstract: A liquid is subjected to ultrasound within a stainless steel pipe (35) of wall thickness 2.5 mm. Three ultrasonic transducers (56) are equally spaced around the pipe, each fixed to one end of a tapered resonant coupler (46) with a nodal flange (48) by which it is supported with its wider end coaxially within a steel collar (38) welded to the outside of the pipe wall. The space around the sides and the end of the coupler is filled by a buffer liquid such as olive oil. When the transducers (56) are energised they resonate, as do the couplers (46), and ultrasound is transmitted through the buffer liquid and the wall into the liquid inside the pipe (35). Within the pipe the intensity can be sufficient to cause cavitation, and so to cause sonochemical effects.

Abstract: A method of forming a transducer device having integral transducer and impedance matching portions includes forming grooves partially through a thickness of a piezoelectric member. A groove volume fraction at the impedance matching portion controls the electrical impedance. The impedance matching portion may be at either or both of the front and rear surfaces of the transducer portion, which generates acoustic wave energy in response to application of a drive signal. The drive signal is introduced by electrodes. In one embodiment, the electrode at the impedance matching portion extends into the grooves, but preferably a filler material is selected and deposited to allow use of a planar electrode. An alternative embodiment to fabricating the transducer device is to assemble piezoelectric material. For example, an integral transducer and impedance matching portions may be formed by using molding techniques or by stacking dimensionally different thin piezoelectric layers.

Abstract: An active impedance modification device or arrangement enables the interaction of sound with a structural surface to be controlled, e.g., so that, reflections from that surface (which can be the hull of a submarine) are substantially reduced or eliminated. The device comprises a coating comprising an inner driver transducer layer in contact with the structural surface an outer receiver transducer layer which receives the sound, in combination with a variable gain, variable phase shift amplifier connected between the interface of the outer layer with the sound carrying medium (e.g., water) and the interface between the second layer and the structural surface. Reflections are reduced by setting the gain and phase shift of the amplifier to simulate the input impedance of the sound carrying medium.

Abstract: An ultrasonic probe having one or more piezoelectric ceramic elements, each having a respective bulk acoustic impedance. Each element has a respective front face and a respective piezoelectric ceramic layer integral therewith to provide efficient acoustic coupling between the probe and a medium under examination by the probe. The respective piezoelectric layer of each element includes shallow grooves disposed on the respective front face of each piezoelectric element. A groove volume fraction of the piezoelectric layer is selected to control acoustic impedance of the piezoelectric layer so as to provide a desired acoustic impedance match between the bulk acoustic impedance of the element and an acoustic impedance of a medium under examination by the probe. Electrodes extend into and contact the grooves, imposing electrical boundary requirements that support a desired electrical field distribution within the element.

Abstract: In an ultrasound transducer arrangement having an electroacoustic transducer part, at least one acoustic matching layer is allocated to the transducer part. The acoustic matching layer is composed of an electrically conductive skeleton having interspaces connected to one another. The skeleton is constructed of particles connected to one another. The size of the particles is smaller than the wavelength of an acoustic wave in a matching layer, as a result of which no significant scattering of the wave occurs in the matching layer. The interspaces are filled with a curable casting compound.

Abstract: An ultrasonic probe including one or more piezoelectric ceramic elements mounted on an acoustically damping support body. Desired acoustic signals are transmitted and received through a front portion of the probe while unwanted acoustic signals are dampened by the support body at the rear portion of the probe. Each element has a respective rear face and a respective piezoelectric ceramic layer integral therewith to provide efficient acoustic coupling between the element and the acoustically damping support body. The respective piezoelectric layer of each element includes shallow grooves disposed on the respective rear face of each piezoelectric element. A groove volume fraction of the piezoelectric layer is selected to control acoustic impedance of the piezoelectric layer so as to provide a desired acoustic impedance match between a bulk acoustic impedance of the element and an acoustic impedance of the acoustically damping support body.

Abstract: A method for bonding together adjoining hollow glass spheres to form an acoustic matching member for a transducer comprises subjecting a mixture of adjoining spheres and a solution of a heat curable resin and a volatile organic solvent to a first temperature to drive off the solvent and then to a second temperature to cure the resin. This causes the spheres to bond together at their points of contact but otherwise voids are formed between the spheres.