Abstract: Acoustic signal sources include acoustic resonators that include acoustic nonlinear materials. Acoustic signals at higher frequencies are mixed in the nonlinear materials to produce a lower frequency acoustic signal. Resonance provides increased efficiency in producing acoustic signals at difference frequencies corresponding to resonance frequencies. Higher frequency acoustic signals used in nonlinear mixing are preferably at frequencies corresponding to resonance frequencies as well.

Abstract: An element, including a first electrode, an intermediate layer, and a second electrode, the first electrode, the intermediate layer, and the second electrode being laminated in this order, wherein the intermediate layer has flexibility, and wherein a deformation amount on a side of the first electrode of the intermediate layer is different from a deformation amount on a side of the second electrode of the intermediate layer when a pressure is applied to the intermediate layer in a direction orthogonal to a surface of the intermediate layer.

Abstract: A liquid-level sensing instrument for determining the level of a liquid in a container or vessel such as a laboratory tube in a rack or a well in a well plate with the container having an acoustically transparent top opening to direct ultrasonic signals to the liquid surface and receive reflected signals where the transceiver sensor instrument is constructed with a piezoelectric focusing sensor that has a concave focusing surface for focusing ultrasonic signals through the opening to the liquid surface in a selected container particularly a container in a group of containers and receiving reflected signals for processing.

Abstract: Systems and techniques for detecting blockage associated with a microelectromechanical systems (MEMS) microphone of a device are presented. The device includes a MEMS acoustic sensor and a processor. The MEMS acoustic sensor is contained in a cavity within the device. The processor is configured to detect a blockage condition associated with an opening of the cavity that contains the MEMS acoustic sensor.

Abstract: A fluid level sensor is configured for identifying a fluid level in a small volume reservoir, such as a fluid reservoir in an ejector head. The reservoir includes a plurality of vertically arranged chambers. A plurality of piezoelectric transducers is distributed over the chambers in a one-to-one correspondence. At least one electrical conductor is electrically connected to each piezoelectric transducer in the plurality of piezoelectric transducers to enable each piezoelectric sensor to receive an electrical signal to a portion of a wall of the chamber to produce an acoustical wave in the chamber and to transmit an electrical signal from each piezoelectric transducer in response to a fluctuating pressure on each piezoelectric transducer produced by the acoustical wave in the chamber.

Abstract: An ultrasonic position sensing system is disclosed. In one embodiment, the system includes an ultrasonic sensor configured to monitor the position of a device. The system also includes ranging logic. The sensor is controlled by the logic to direct an ultrasonic pulse toward the device. The logic is configured to compute the transit time and the velocity of the ultrasonic pulse. Based on these parameters, the logic computes the path length between the sensor and the device, which corresponds to the location of the device relative to the location of the sensor. In further embodiments, the ultrasonic positioning system may include multiple sensors in communication with the ranging logic for monitoring multiple devices.

Abstract: The disclosure, in one aspect, provides an apparatus that includes an acoustic transducer and a backing in contact with a side of the transducer. The backing includes substantially unidirectional fibers in a matrix of a material that has high shear wave acoustic attenuation. The fibers contact the side of the transducer at an angle configured to convert substantially all of the compressional waves that enter the backing for the transducer into shear waves, which shear waves are then attenuated by the matrix of the backing material.

Abstract: An acoustic wave transducer includes at least one electroacoustic motor, a horn having an inner wall and an outer wall, a counterweight, and a hollow housing having an inner wall and an outer wall and at least one acoustic opening. The electroacoustic motor is connected to the horn and to the counterweight along an axis, and the electroacoustic motor is capable of exciting the horn at about at least one resonance frequency. The housing is connected to the counterweight and surrounds the motor and the horn, the outer wall of the horn being arranged opposite an acoustic opening of the housing, and the space between the inner wall of the housing and the inner wall of the horn defines a cavity that contains a fluid. The transducer includes acoustic attenuation elements connected to the outer wall of the housing in order to attenuate the emission and/or reception acoustic waves at the frequency at least in a direction transverse to the emission/reception axis.

Abstract: A multilayer backing absorber for use with an ultrasonic transducer comprises a plurality of absorber elements, each absorber element having at least one metal layer and at least one adhesive layer, wherein the backing absorber is adapted to be coupled to a vibrating layer of the ultrasonic transducer.

Abstract: A multilayer backing absorber for use with an ultrasonic transducer comprises an elemental multilayer having at least one metal layer and at least one adhesive layer, wherein the backing absorber is adapted to be coupled to a vibrating layer of the ultrasonic transducer.

Abstract: A transducer device includes a coupling cavity, a first resonant element and a second resonant element. The first resonant element is coupled to the coupling cavity and configured to send or receive acoustic signals. The second resonant element is coupled to the coupling cavity and configured to modify a frequency response of the first resonant element via the coupling cavity.

Abstract: Methods and systems utilizing seismic sensors configured or designed for use in seismic signal detection. An electrical current is applied to a seismic sensor such that the moving coil is located at a neutral position relative to the magnetic field in the seismic sensor to compensate for gravitational acceleration.

Abstract: An electro-mechanical transducer is disclosed, which provides a wideband response by activating successive multiple resonant frequencies in a way which provides additive output between the resonant frequencies with reduced cancellation below the first resonance and means for controlling the response by reducing the voltage drive. A multiply resonant wideband high output transducer is disclosed.

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: A transducer device includes a coupling cavity, a first resonant element and a second resonant element. The first resonant element is coupled to the coupling cavity and configured to send or receive acoustic signals. The second resonant element is coupled to the coupling cavity and configured to modify a frequency response of the first resonant element via the coupling cavity.

Abstract: An acoustic transducer array and method of baffle construction is presented to provide an improved array for use in underwater installations. The array is presented wherein a significant majority of the acoustic energy receiving surface is formed by lightweight acoustic baffling material while still maintaining a fully functional, fully populated array. The acoustic baffle constructed is incompressible and suitable for deep water operation while demonstrating both improved acoustic performance and positive buoyancy when necessary. In addition, the invention eliminates the non-uniform element to element spacing that occurs between sub-panels in similar arrays.

Abstract: An acoustic isolator for use with tubular assemblies such as drillpipe or production tubing comprising an acoustic wave transmitter, the acoustic isolator comprising, in series connection, an odd integer ?/4 multiple tuning bar of first acoustic impedance adjacent the acoustic wave transmitter, an odd integer ?/4 multiple reflector tube of second acoustic impedance, and a snubber of third acoustic impedance, wherein there is an acoustic impedance mismatch between the odd integer ?/4 multiple tuning bar and the odd integer ?/4 multiple reflector tube and an acoustic impedance mismatch between the odd integer ?/4 multiple reflector tube and snubber, such that a ‘down’ wave propagated toward the isolator is reflected back substantially in phase with an ‘up’ wave propagated from the acoustic wave source away from the isolator.

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: An ultrasonic transducer utilizes an acoustic transmission line to increase the sensitivity of both the transmitting response and the receiving response. The resonant element of the transducer could employ a ceramic disc operating in the radial resonance mode for its transduction means, or it could be a half wavelength resonator utilizing a forward transmission line, a rear transmission line, and a non-resonant ceramic for transduction. The shape of the forward transmission line is designed to generate the desired acoustic radiation pattern at the frequency of resonance, which could be a broad or narrow conical beam or a fan shaped beam. A sealed housing structure is disclosed that contains the forward transmission line that is acoustically disconnected from the rest of the housing. This housing provides improved environmental protection and allows for easy mounting of the transducer without effecting its electroacoustic response characteristics.

Abstract: An acoustic isolator for attenuating through-tool acoustic signals comprises a plurality of u-shaped link members, where each link member has two sets of ears. A plurality of yoke members are adapted to fit between cooperating sets of ears. A plurality of pins connect the plurality of u-shaped link members to the plurality of yoke members for providing limited flexural compliance. The isolator may be made from metallic and/or composite materials.

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: Microelectromechanical systems (MEMS) include critical devices for various highly sensitive applications. However, MEMS operation may be impaired by vibration. A modular vibration control pedestal for integration with a MEMS is provided according to embodiments of the present invention which includes a piezoelectric perovskite oxide disposed on a substrate and a shape memory alloy component component disposed on the piezoelectric perovskite oxide. In particular embodiments of a MEMS device including a modular VCP, vibration is reduced by at least 50%.

Abstract: Disclosed is an underwater projector projecting a sound underwater. The underwater projector includes a first disk-type resonator unit, a second disk-type resonator unit, and a central space. The second disk-type resonator unit is installed so that a central axis corresponds with that of the first disk-type resonator unit. The central space is set up between the first disk-type resonator unit and the second disk-type resonator unit, and water can enter the central space.

Abstract: Apparatus and methods for acoustically isolating logging tool receiver and transmitter sections. One or more modular isolators is arranged between the receiver and transmitter sections. The modular isolators comprise a high tensile strength while also providing for a high wave attenuation level. The modular isolators are mechanical mass-spring systems capable of absorbing acoustic waves propagating along the logging tool. The mass is a swinging sleeve, and the spring includes a Belleville spring stack. The use of the strong modular isolators provides acoustic isolation between the transmitters and receivers for the complete sonic frequency band at multiple modes.

Abstract: A method and apparatus for damping an ultrasonic transducer suitable for time of flight ranging and level measurement systems. The ultrasonic transducer comprises a damping component which absorbs vibrations in the transducer to reduce the ringing effect. The damping component is subjected to plasma etching to produce a surface which readily bonds to component(s) of the transducer. According to one aspect, the damping component is formed from an inert elastomer, such as silicone rubber, and the transducer component is made of stainless steel.

Abstract: A piezoelectric vibrator having excellent shock resistance and high reliability is offered. The centers of first and second piezoelectric vibrating plates are supported by pillars on a main surface of an enclosure and nearly or substantially parallel to the main surface of the enclosure. Spacers having a Young's modulus of less than 2 GPa are mounted on both end sides of the second piezoelectric vibrating plate to prevent contact between the vibrating plates, thus preventing damage. Other spacers are mounted on the main surface of the enclosure in positions corresponding to the first-mentioned spacers to prevent contact with the main surface of the enclosure, thus preventing damage to the second piezoelectric vibrating plate.

Abstract: An electromechanical device for generating elastic waves in a material medium such as the subsoil in a frequency range where the wavelengths of the waves generated are great in view of the dimensions of the device, and method of implementation. The device comprises one or more vibrators which are buried in the medium, associated with a control system. Each vibrator comprises at least one inertia mass (1), several plates (2, 3) providing mechanical coupling with the medium, electromechanical transducers (4, 5) connecting inertia masses (1) to plates (2, 3). A control system (7) applies to the various transducers (4, 5) respective control signals so that the resulting elastic wavefield generated in the medium by the device is preferentially oriented in one or more directions.

Abstract: The present invention relates to high-frequency antennas with high transmission power. The invention consists in making the backing layer of such an antenna with a heat-conductive foam and enables the transmission power to be appreciably doubled.

Abstract: A plurality of heavy mass irregularities attached to an inner wall of the drill collar attenuate waves traveling through the collar. The plurality of heavy mass irregularities are spaced and sized for the maximum attenuation of acoustic pulses in a predetermined frequency range. The mass irregularities may be rings secured to the inner surface of the collar by neck pieces, extending outwardly from the outer circumference of the ring. The mass irregularities may be made of steel or tungsten and are between six and ten in number. The spacing of the irregularities may lie between twelve and fourteen centimeters. A center pipe may be included to isolate the irregularities from the fluid flow associated with the drilling operation. The pipe may be of a soft material such as rubber to reduce transfer of acoustic noise along the drill string. The irregularities may be in an oil based fluid with the pipe fitting closely in the center of the rings.

Abstract: An apparatus for performing acoustic investigations while drilling a borehole in a subsurface geological formation comprises a longitudinally extending assembly conveyed in the borehole on a drilling tubular. The assembly and the drilling tubular have a drilling fluid flowing through a longitudinally extending passage therein. An acoustic transmitter is supported by the assembly. The transmitter generates acoustic signals in the assembly, the borehole and the subsurface formation. An acoustic receiver is spaced apart from the transmitter and receive the acoustic signals. An attenuator is located in the assembly between the acoustic transmitter and the acoustic receiver for attenuating the acoustic signals in the assembly within a predetermined frequency range. The attenuator comprises a tubular element of a composite material having a substantially cylindrical outer surface. The outer surface has a plurality of spaced apart masses having a predetermined spacing, mass and length firmly attached thereto.

Abstract: An acoustic wave sensor utilizes one or more acoustic waves trapped in an acoustic wave cavity to detect the presence of one or more substances on a surface of the acoustic wave cavity. To detect the presence of ice, a trapped torsional acoustic wave is used. To detect water, an acoustic wave with flexural or compressional components is used. The sensor includes a number of transducers adjacent the acoustic wave cavity where a controller drives different sets of the transducers to generate different acoustic waves.

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

Abstract: The invention is an modified audible signal, such as a piezoelectric noise-making and audible signaling device, which further includes a hydrophobic covering material, such as polytetrafluoroethylene (PTFE). The hydrophobic covering material is known to be water resistant, but does not effect the sound of the audible signaling device, thereby delaying or preventing the failure of the audible signaling device from water corrosion.

Abstract: An electro-mechanical transducer is disclosed, which provides a wideband response by activating successive multiple resonant frequencies in a way which provides additive output between the resonant frequencies. A three mode wideband high output transducer is also disclosed along with an electro-mechanical feedback system which provides a smoothed response as well as array control under multiple element usage.

Abstract: The present invention provides a microfabricated acoustic transducer with suppressed substrate modes. The modes are suppressed by either thinning the substrate such that a longitudinal ringing mode occurs outside of the frequency band of interest or by applying a judiciously designed damping material on the backside of the transducer substrate.

Abstract: A shock wave source has a coil carrier, a coil, having a metallic membrane separated from the coil in insulating fashion for generating shock waves. The coil carrier is formed of a material that damps the formation and/or the propagation of audible acoustic waves in the generation of shock waves.

Abstract: A shock wave source has a coil carrier, having a longitudinal axis, a coil and a metallic membrane separated from the coil in insulating fashion for generating shock waves. The coil carrier has a generated surface, a first cover surface facing toward the coil and a second cover surface facing away from the coil. For reducing the low-frequency sound generation when generating shock waves, a cross-sectional area of the coil carrier intersected at a right angle by the longitudinal axis has a non-circular contour. A reduction of the audible sound generation when generating shock waves can also be achieved when the second cover surface of the coil carrier is non-flat.

Abstract: The invention is directed towards structures for use with micro-formed membrane ultrasonic transducers, and methods for fabricating the structures. In one embodiment, the transducer includes a planar member having a piezoelectric material and spaced apart electrodes disposed on the planar member and coupled to the piezoelectric material for applying an electric field to the layer, and an acoustic backing member joined to the electrodes. In another embodiment, the transducer includes a planar member having a piezoelectric material that adjoins a semiconductor material, the semiconductor material having monolithically formed active circuits formed in the layer and coupled to the piezoelectric material. In still another embodiment, the transducer includes a planar member having a piezoelectric material, and an acoustic backing member having an adjoining layer of a semiconductor material having monolithically formed active circuits, the active circuits being coupled to the electrodes.

Abstract: The present invention relates to a directional electro-acoustic transducer and arrays of transducers of the cylindrical or ring electro-mechanical type in conjunction with a partial conformal acoustic baffle. Such a device has very desirable directional beam patterns that are nearly frequency independent over a significant frequency range and the radiation is has a characteristic broadband frequency response due to multimode excitation.

Abstract: A seismic sensor contains a geophone (4) disposed within a housing (12). The sensor is also provided with locking means (14, 19, 21) that can either lock the geophone 4 relative to the housing, or can allow the geophone to rotate within the housing. The geophone (4) is enclosed in a casing (1) which is so constructed that the overall mass distribution of the casing and geophone is uneven. The casing and geophone assembly thus adopts a preferred orientation when the sensor is unlocked. A liquid can be disposed within the housing, so that the casing (1) and geophone (4) can float when the sensor is unlocked.

Abstract: A microfabricated acoustic transducer with suppressed substrate modes includes a diaphragm containing an upper electrode suspended above a substrate containing a lower electrode; the substrate may or may not contain electronic circuits. The substrate modes are suppressed by either thinning the substrate such that a longitudinal ringing mode occurs outside of the frequency band of interest or applying a judiciously designed damping material that absorbs acoustic energy from the substrate on the backside of the transducer substrate, or by both thinning the substrate and applying the damping material. The damping material has an acoustic impedance that matches the acoustic impedance of the substrate and is lossy.

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: 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: In one aspect, the invention involves an acoustic logging tool for performing acoustic investigations of subsurface geological formations. In one embodiment, the tool comprises a generally longitudinally extending tool body adapted for positioning in a borehole. At least one transmitter is mounted on the tool body to emit acoustic energy. At least one receiver is also mounted on the tool body at a location axially displaced from the at least one transmitter. The receiver is adapted to receive acoustic energy. An attenuator is also positioned along the body and includes at least one cavity having a plurality of particles disposed therein. The attenuator as disclosed herein may be applied to other logging tools for protecting tool components and enhancing measurement quality. Methods for attenuating acoustic energy transmitted through the body of an acoustic logging tool or other logging tools are also disclosed.

Abstract: The present invention provides a microfabricated acoustic transducer with suppressed substrate modes. The modes are suppressed by either thinning the substrate such that a longitudinal ringing mode occurs outside of the frequency band of interest or by applying a judiciously designed damping material on the backside of the transducer substrate.

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: 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: A multilayer backing for an ultrasonic transducer array comprises at least two layers in contact with each other. The first layer is formed from a first composition comprising an epoxy resin base and a powder. The second layer is formed from a second composition comprising an epoxy resin base, a powder, and at least one of a phenolic shell micro-balloon and a plasticizer. The first layer is more rigid than the second layer so that the first layer provides mechanical support for the array, while the second layer provides maximal sound absorbance.

Abstract: The damping of membranes of ultrasound transducers in an arrangement occurs at the front side directly on the membranes by applying a polymer layer, whereby the working temperature dependent on the operating frequency of the ultrasound transducer lies within the glass transition range of the polymer layer.