Abstract: The present application relates to a lexicon learning-based heliumspeech unscrambling method in saturation diving. In a system including divers, a correction network, and an unscrambling network, a common working language lexicon for saturation diving operation is established and is read by the divers respectively in different environments, to generate supervision signals and vector signals of the correction network, and the correction network learns heliumspeeches of the different divers at different diving depths to obtain a correction network parameter, and corrects a heliumspeech of a diver to obtain a corrected speech; and the unscrambling network learns the corrected speech and completes unscrambling of the heliumspeech.

Abstract: A transducer includes: a piezoelectric element; and a film body including a film support portion having a hollow portion, and a vibration film connected to the film support portion and displaceable in a film thickness direction, the film body having the piezoelectric element stacked over the vibration film. The piezoelectric element includes: a first stacked body having a first pair of electrodes and a first piezoelectric film sandwiched between the first pair of electrodes; and a second stacked body having a second pair of electrodes and a second piezoelectric film sandwiched between the second pair of electrodes, the second stacked body being separated from the first stacked body.

Abstract: A sound production device includes a substrate having a cavity and a plurality of cantilever diaphragms fixed on the substrate. Each of the plurality of the cantilever diaphragms includes a fixed end fixed on the substrate and a free end extending from the fixed end to a position suspended above the cavity. The free end includes a first surface and a second surface oppositely arranged. The free end and the substrate or other free ends are spaced to form a gap. The sound production device further includes a first dielectric elastomer actuator, a second dielectric elastomer actuator, and a flexible connector. The sound production device of the present disclosures adopts dielectric elastomer actuators on both of the upper and lower sides of the cantilever diaphragms to together act on the cantilever diaphragms, thereby improving the linearity of the sound production device.

Abstract: A seismic pressure and acceleration sensor can include a hydrophone having a volume encapsulated by an enclosure. The enclosure can include, a pressure-sensitive surface and a pressure-insensitive support structure. The sensor can also include an accelerometer positioned within the encapsulated volume. The accelerometer is mechanically isolated from the pressure-sensitive surface and mechanically coupled to the pressure-insensitive support structure.

Abstract: A plurality of sensors and a controller are disposed in a marine seismic streamer. Each of the sensors comprises an enclosure having two opposing interior walls, first and second piezoelectric elements disposed on the opposing interior walls, a third piezoelectric element disposed on a flexible substrate within the enclosure between the opposing interior walls, a pressure signal output node and an acceleration signal output node disposed on the exterior surface of the enclosure. A combined pressure signal derived from the pressure signal output nodes of the plural sensors is coupled to a pressure signal input of the controller. A combined acceleration signal derived from the acceleration signal output nodes of the plural sensors is coupled to an acceleration signal input of the controller. The streamer may be towed, and the combined pressure and acceleration signals may be recorded in a computer-readable medium.

Abstract: A hydrophone may include a first piezoelectric cable including alternating sections of positive polarity and negative polarity, and a second piezoelectric cable including alternating sections of negative polarity and positive polarity. At least a portion of each section of positive polarity of the first piezoelectric cable may be bonded or adhered to at least a portion of a section of negative polarity of the second piezoelectric cable. A method of manufacturing a hydrophone may include winding or coiling a first piezoelectric cable and a second piezoelectric cable at the same time to create a series of wound sections including cables, the wound sections alternating with a series of not wound sections including the cables.

Abstract: A oscillator in a liquid includes an actuator element oscillating in a reciprocating manner, and a sound-producing element attached to the actuator element, whereby the actuator element generates a motion in the sound-producing element for producing a sound. The oscillator is made open, whereby the pressure of liquid acts both on a first surface and on a second surface of the wall of the sound-producing element while the sound source is in the liquid. The material and/or structure of the wall of the sound-producing element is provided to be such that the distance between the first surface and the second surface of the wall varies as sound is produced.

Abstract: Multiple twisted or rotated arrays are provided. For example, a memory alloy may allow manufacture of multiple rows of elements on a flat substrate. The memory of the alloy is activated to twist different rows in different ways, such as two adjacent substantially parallel but oppositely rotated arrays. By selecting different apertures along a given twist, different planes are scanned due to the difference in direction of the elements of the aperture. By selecting different apertures on differently rotated arrays, a larger volume may be scanned.

Abstract: Methods of making an energy harvesting device are described. A case and integrated piezoelectric cantilever to harvest vibration energy from an environment being sensed is produced via a print forming method injection molding method. The cantilever device consists of a piezoelectric material member, and a proof mass of high density material coupled to the piezoelectric member. The print forming method is used to build up the base and walls of the device as well as the neutral layers of the piezoelectric member. Metal layers are printed to form the electrode layers of the piezoelectric member and the electrical contact portions of the device. Passive components can also be formed as part of the layers of the device. The entire assembly can be encapsulated in plastic.

Abstract: An acoustic transducer that enables acoustic radiation at a low frequency and that also improves efficiency of the acoustic radiation into liquid is provided. The acoustic transducer according to the present invention includes bending vibration module 7 that is formed by at least one bending oscillating body 1 that has at least one plate type piezoelectric resonator 2 and diaphragm 3, and supporting member 9 for supporting bending vibration module 7. A plurality of bending vibration modules 7 are cylindrically arranged, and supporting members 9 radially protrude from shaft 8 provided at the center of the cylindrically arranged bending vibration modules 7 and are joined with the ends of diaphragms 3 of adjoining bending vibration modules 7.

Abstract: A micro-cantilever of a simple structure and capable of obtaining a larger displacement at a low voltage including a plate-like piezoelectric substrate having electrode films as an upper electrode and a lower electrode formed on both surfaces thereof, a plate-like resilient member in close contact with the piezoelectric substrate on the side of the lower electrode and a support for supporting a driving member in a cantilever manner, in which a thin-walled portion is formed to the vicinity of a base portion of the driving member supported by the support.

Abstract: The invention relates to a micro-optical arrangement with which in particular optical properties of an optical element or its influencing of electromagnetic radiation may be changed. Thereby the optical elements with a reflecting surface are preferred. It is the object of the invention to provide for a changeability of optical parameters, in particular of the focal width with small time constants, in an inexpensive manner and with a small required constructional volume. The micro-optical arrangement according to the invention comprises a plate-like optical element onto which electromagnetic radiation is directed on an optically effective surface. The optical element thereby is fixed or clamped at least at one outer edge point. The optical element is elastically deformed due to mass inertia as a result of a translatory movement at least approximately parallel to the optical axis between two reversal points (?z0, z0).

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: Various sensors use an electro-active device (11) electrically connected to a detector circuit. The electro-active device (11) comprises an electro-active structure in the form of a continuous electro-active member (12) curving in a helix around a minor axis (13) which is in itself curved for example in a helix around a major axis (14). On activation by relative displacement of the ends (16) of the device (11), the electro-active structure twists around the minor axis due to the fact that the minor axis (13) is curved. The continuous member (12) has a bender construction of a plurality of layers (21) and (22) including at least one layer of electro-active material so that concomitantly with the twisting the continuous member (12) bends generating an electrical signal detected by the detector circuit. The electro-active device (11) is advantageous as a sensing element in a sensor because it has a large displacement, high sensitivity and low compliance.

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: A piezoelectric audio transducer suitable for underwater use comprises a piezoelectric ceramic plate within a housing having open front face and back faces exposing the front and back faces of the ceramic plate to ambient pressure. The ceramic plate can be supported in spaced relation from the housing by, for example, open cell foam, so as to be vibrationally isolated from the housing.

Abstract: Random copolymers including vinylidene fluoride and hexafluoropropylene that exhibit a large electrostrictive response when subjected to an electric field, articles including such polymers, and methods of preparing the polymers and articles. Electrostrictive responses greater than about 4 percent are obtainable at electric field strengths of 50 megavolts per meter.

Abstract: An improved transducer arrangement for low frequency sonar projectors that convert electric signals to mechanically generated acoustic signals. In one embodiment the arrangement has both a convex flextensional transducer and a concave flextensional transducer. An open side of the convex transducer is attached to an open side of the concave transducer by an intermediate bulkhead which closes each of the attached open sides. An end plate is attached to another open side of the convex transducer and another end plate is attached to another open side of the concave transducer such that the end plates close the attached open sides. In another embodiment, transducer assembly has a convex transducer having end plates and a concave transducer having end plates. Either one of the endplates of the concave transducer is attached to one of the endplates of the convex transducer, or an endplate of the concave transducer is also an endplate of the concave transducer.

Abstract: An omni-directional dual bilaminar hydrophone particularly suitable for use in a towed array consisting of a cylindrical tubular housing whose ends are sealed by bilaminar piezoelectric ceramic/diaphragm subassemblies capable of axially deforming to produce an electric signal proportional to the intensity of the sound vibrations sensed. The density of the air-backed hydrophone may be readily predetermined by the spacing between the ceramic/diaphragm assemblies, and/or diameter of the housing. A plurality of such hydrophones internally connected in series assembled within a cylindrical flexible fluid filled support, such as a hose, may be used as a towed array wherein the separate hydrophones thereof are electrically connected in series parallel, or series-parallel, to produce a signal from sonic vibrations.

Abstract: There is provided an acoustic source especially for use in seismic studies at sea. The acoustic source has a longitudinal axis and sound emitting surfaces adapted to be put into sound emitting movements towards and away from each other by use of a drive unit. The sound emitting surfaces comprise two curved plate members having upper and lower ends essentially symmetrically positioned in relation to the longitudinal axis of the acoustic source, and forming a convex cross section with their respective upper and lower edges converging towards each other. The upper and lower edges of the sound emitting surfaces, respectively, are connected to each other with two corresponding side elements, the side elements each being connected to at least one hinge stretching along at least a part of the length of the source.

Abstract: Acoustic source, especially for use in seismic studies at sea, with sound emitting surfaces adapted to be put into sound emitting movements toward and away from each other by use of a drive unit in a known manner, in which the sound emitting surfaces comprise two curved plate members essentially symmetrically positioned in relation to the longitudinal axis of the source, forming a convex cross section with their respective upper and lower edges converging towards each other, and the respective upper and lower edges of the sound emitting surfaces are flexibly connected to two corresponding side elements positioned between them, and that the source comprises a rigid frame for supporting the drive unit, comprising at least two rigid slide rods stretching through the side elements, and that rigid covers are mounted on the slide rods, covering at least the whole side elements, thus forming rigid, covering surfaces with a constant distance between the covers.

Abstract: A slotted cylinder transducer is provided having a cylindrical metal or cosite material shell. A cylindrical piezoelectric driver is bonded to the inside of the shell with an opening corresponding to the slot. The shell thickness is tapered radially about the longitudinal axis such that the thickness is a maximum 180.degree. away from the slot and decreases progressively to a minimum adjacent each side of the slot. The piezoelectric driver is reverse tapered from the shell taper in that the thickness of the driver is a minimum 180.degree. away from the slot and increases progressively to a maximum adjacent each side of the slot. This taper places a larger volume of the driver material in the slot region of the shell where the maximum radial displacements occur, thus providing higher acoustic energy levels. When used as a hydrophone to detect acoustic signals in the surrounding medium, the larger volume of material at the point of maximum displacement provides increased signal detection capability.

Abstract: A vibration detector is disclosed. The vibration includes a ring (2) closed at its opposite ends by two ring ends (3, 4), that is externally covered with a sheath (11) made from an elastic material transparent to vibrations, two supporting plates (5) with a flexible central part (6) and a reinforced peripheral part (7) resting on the two ring ends. An inner cavity (8) between the two plates (5) is filled with liquid communicating through ports (10) and sheath (11) with the outside environment. Two sensitive elements (9) such as piezoelectric disks for example are fastened to the flexible central parts (6) on their faces of the interior of the cavity (8). The sensitive elements (9) are well protected from the outside environment and their sensitivity is not substantially influenced by variations in the static pressure. The invention has an application for detection of acoustic or seismic waves.

Abstract: The piezoelectric-acoustic transducer of the present invention has a hollow case provided with a sound hole. A piezoelectric actuator is disposed inside this case that has one end fixed to the case and that bends in the direction of the thickness of the case when voltage is applied. A diaphragm is secured to one portion of the piezoelectric actuator and is positioned at a distance from the piezoelectric acturator in the direction of the thickness of the case.

Abstract: A composite sensor includes at least one layer comprising a piezoelectric material such as a molecularly poled polymer material or a ceramic material having disposed therebetween a material which enhances the piezoelectric properties of the piezoelectric material. One pair of edges of said composite sensor are constrained from expanding in response to a force applied to the sensor.

Abstract: An active element in a hydrophone includes a piezoelectric hydrophone crystal mounted to a backing plate. The piezoelectric crystal may be divided into separate segments. If so segmented, the polarities of the segments are oriented in the same direction. Whether or not segmented, the center portion or segment of the crystal is in abutting contact with a motion limiter, which acts as a spring between the piezoelectric crystal and the casing surrounding the crystal and backing plate. The portions or segments or the crystal are connected to electrical signal leads with the minimum amount of solder necessary to ensure secure electrical and mechanical coupling, thereby reducing the effects of the solder connection on the stress flux profile in regions of the crystal close to the solder.

Abstract: An active element in a hydrophone includes a piezoelectric hydrophone crystal mounted to a backing plate. The piezoelectric crystal may divided into separate segments. If so segmented, the polarities of the segments are oriented in the same direction. Whether or not segmented, the center portion or segment of the crystal is supported in part by a center pin at its center. Thus, in the presence of a downward pressure, the end portions or segments develop a concave flexure and the center segment, due to the center pin support, develops a convex flexure. With this reverse flexing phenomenon, the center portion segment develops an electrical signal of opposite polarity from those of the end segments. By carefully selecting the areas of the end segments, and electrically coupling the segments so that the harmonics of the various segments are added out of phase, the distortion introduced the harmonics of the various phases subtract.

Abstract: A high frequency transducer capable of transmitting and receiving having an operational range from 100 kHz to 2 MHz, a free field voltage sensitivity (FFVS) greater than -218 dB re 1 V/.mu.Pa (300 kHz), and a maximum hydrostatic pressure rating of 20.68 Mpa (3000 psi). The sensor element is made of lead titanate with a radial mode of 150 kHz being suppressed by the use of a rubber grommet surrounding the lead titanate element. The sensor element is retained within a sensor housing by a plurality of annealed iron wires attached to an annealed iron ring, both of the faces of the sensor housing are then covered with an acoustically transparent window of natural gum rubber. The sensor housing is attached to a non-metallic preamplifier housing made of a rigid polyurethane containing a preamplifier circuit, a transmit protection circuit, and a plurality of relays for switching the preamplifier circuit during the transmit and receive modes.

Abstract: A low frequency flex-beam underwater acoustic transducer has a base, a flexible beam having one end cantilever mounted on the base, and piezoelectric driving means, for flexurally driving the beam. The piezoelectric driving means operates in the k.sub.31 and/or the k.sub.33 mode.

Abstract: A mud pulser for measurement-while-drilling applications is disclosed which employs piezoelectric transducers to provide for variations in the mud flow through a mud pulser sleeve. The piezoelectric transducers used in the mud pulser are comprised of two piezoelectric elements bonded together in a bender bar transducer configuration, thin metallic sheets to improve the rigidity of the transducer and to protect the ceramic material and electrodes from the effects of abrasive drilling fluid, and simplified mounting means.

Abstract: A piezoelectric ceramic hydrostatic sound sensor or transducer having high ensitivity to hydrostatic pressure is made by placing a flat plastic disc between two flat layers of green ceramic material, compressing and fusing the layers, heating to a first temperature at which the plastic decomposes, leaving a flat void in the ceramic, and heating to a second temperature at which the ceramic sinters. The transducer is provided with electrodes on its top and bottom surfaces. In a further improvement, ceramic particles are provided which are entrapped in the void; they render the sound sensor sensitive to inertial forces. In yet another improvement, the inside walls of the void are coated with a conductive noble metal connected to a terminal wire, whereby an additional electrode is provided for sensing the electromechanical response of the transducer.

Abstract: A method of forming a laminated piezoelectric structure is disclosed wherein a plurality of polarized piezoelectric films of vinylidene fluoride and trifluoroethylene are solvent welded together. The solvent welding solution comprises a copolymer of vinylidene fluoride and trifluoroethylene and a suitable solvent. The transducers produced from such a laminated structure are also disclosed.

Abstract: A hydrophone is provided for use with a hydrophone array enclosed in a streamer cable that is deployed in a body of water. The active transducer elements of the hydrophone are electrically isolated from the sealed metal case in which they are mounted. The signal input and output terminals are protected from short-circuiting due to water invasion of a faulty streamer cable jacket.

Abstract: The FLEXBAR is a sonar transducer element that is basically a piezoceramic "free-free" flexure bar, but modified so as to radiate as a "monopole" rather than as a "dipole", and retaining the unique properties of being nodally mounted and dynamically balanced. One of the important consequences of this simple modification is the fact that the reaction forces on the FLEXBAR mountings and, the concomitant structure-borne vibrations, are virtually eliminated. This property, and related properties, result in unexpected but significant improvement in the performance of low-frequency, high-power, board-band sonar transducer arrays.

Abstract: A hydrophone for the detection of sound or vibrational waves, comprising a piezo electric transducer within a Faraday cage such that it is in contact with and yet isolated from a deformable pressure transmitting medium that carries vibrations. The Faraday cage reduces noise interference. The deformable medium is usually a fluid and preferably a vegetable oil, but can also include a silastic compound couple. One side of the Faraday cage is a ground plane of a surface-mount printed circuit board. Components of an electronic circuit for conditioning the signal are mounted on the printed circuit board and include a buffer having an ultra-high impedance input and a very low impedance output. The circuit has a low power draw and is powered by a replaceable battery.

Abstract: A single stack of double poled piezoelectric ceramic elements (202) create a monolaminar bender bar (200) which can be used in acoustic applications. The stack is lined up such that adjacent elements (202) in bender bar (200) have oppositely poled top and bottom sections. A positive voltage (230) is connected to electrical connection plates (214) which are positioned between every other piezoelectric element (202) in the stack and a negative voltage (232) is connected to electrical connection plates (214) which are between the remaining piezoelectric elements (202). Applying a voltage causes the stack to bend, wherein the piezoelectric elements (202) in the top half of the bender bar (200) all expand while the piezoelectric elements (202) in the bottom half of the bender bar (200) all contract.

Abstract: The housing of a transducer supports both dynamic and static pressure sensors to obtain depth information as well as pressure wave signals. A semiconductive diaphragm with diffused resistances connected in a bridge is used as the static sensor which is centrally located on an end face of the housing. Several parallel-connected dynamic sensor elements are arrayed around the static sensor. Each dynamic sensor element is an edge supported brass disk with a thin piezoelectric ceramic disk soldered to it such that the disks flex in response to low frequency pressure waves to generate corresponding electrical signals. A low noise amplifier and filter is capacitively coupled to the dynamic sensor array to process hydrophone signals at a frequency below 1 Hz.

Abstract: A hydrophone is provided having at least one flexible piezoelectric sensitive element applied to a support, each sensitive element being formed of a flexible piezoelectric film associated with two electrodes and is applied to a synthetic plastic material support one face at least of which has hollow parts of very different shapes, for example an homogeneous distribution of cups, honeycombs, holes, etc, whose dimensions are determined as a function of the mechanical characteristics of the films used. The stresses applied thereto result in deforming each film inwardly of the hollow parts, which very greatly increases the sensitivity.

Abstract: A bender acoustic transducer has a flat, piezoelectric element affixed to a flat, elongated inert element. The ends of the inert element are hinged on a supporting rectangular frame which has a rectangular opening. Two sides of the elements are exposed so that when a voltage is applied, a dipole acoustic wave is generated by the transducer.

Abstract: An electro-acoustic transducer has a transducer plate having a piezo-electric layer attached thereto. The electro-acoustic transucer is clamped between bearing members at an annular edge region which is free of the piezo-electric layer. The piezo-electric layer is provided with electrodes which extend into the annular free region of the transducer plate. At least one of the bearing members has electrically conductive zones which press directly or indirectly against the electrodes and which press against electrical plug elements on a housing for the transducer.

Abstract: A directional flextensional transducer including a transducer shell capable of operation in odd and even drive modes and a transduction drive bar or the like. The transduction drive bar is excited in an even mode to impart extensional motion thereto and is simultaneously excited in an odd mode to impart inextensional motion thereto. The combined excitation causes the flextensional transducer shell to move unidirectionally.

Abstract: An acoustic transmitter for borehole logging includes a flexure disc acoustic source affixed to one end of an open-ended pipe. A rubber boot surrounds the pipe and flexure disc source and fluidly isolates them from the surrounding borehole fluid. Oil fills the rubber boot and pipe, such that the borehole fluid pressure is transmitted through the rubber boot to the oil. The flexure disc source is electrically excited to cause the transmitter to generate acoustic energy tube waves at one of the resonances of the flexure disc source within the seismic frequency range.

Abstract: An ultrasonic transducer includes a piezoelectric polymer film folded as at least two layers and having electrodes on both the surfaces thereof. The ultrasonic transducer is responsive to a signal, applied across electrodes, to produce an ultrasonic wave to be focused at one spot so that it is converted to an electric signal. In this ultrasonic transducer, a groove or through holes are formed on and along the folded area of the piezoelectric polymer film.

Abstract: A flexural disk transducer includes two thickness poled piezoelectric disks each of which is bonded on one side to a metal backing plate of substantial thickness and on the other side to a thin metal "skin" or plate. The metal backing plates are, in turn, bonded to a ring-shaped metal spacer member having a rectangular "C" shaped cross section with the axially extending web made sufficiently thin and the radially extending flanges grooved such that the spacer member is sufficiently compliant that it has minimal effect on the resonant frequency of the disks. The disks are coated on each side with a thin layer of conducting material such as silver or copper and have radially extending wires serving as connections to such layers. The entire assembly is contained within a handling ring with the wire connections and the space between the assembly and the handling ring filled with electrical potting material. A thin layer of neoprene rubber covers the exposed faces of the disks for waterproofing.

Abstract: An underwater acoustic wave transmitting and receiving unit having excellent characteristics for both transmitting and receiving and providing stable characteristics over long operating periods. A plate-shaped polarized piezoelectric resonator is provided formed of at least one plate made of a complex of fluorosilicon rubber and lead titanate. The resonator is sealed in a rubber casing filled with an insulating liquid matching the water around the casing in acoustic impedance.

Abstract: An arrangement in a piezoelectric hydrophone that is provided with a protective outer housing enveloping a waterproof closed casing (2). Said casing is provided with two mutually opposed and parallel diaphragm wafers (3) on the insides of which piezoelectric crystals (4) being metal coated on their outsides are respectively attached. A connecting wire is extended from said case through its hollow central portion (6). Said central portion (6) is formed by at least two ceramic elements (7) joined along a plane parallel with the diaphragm wafers and provided with a metalization (11) in the mutual contact areas (9, 10). In the cavities (12) respectively of the two elements (7) stiffening ceramic disks (8) are provided and attached to the elements (7) by the aid of a matching projection (13). The inward facing poles of the piezoelectric crystals are conductively connected with the metalization in the contact plane of the elements, and an additional wire (5) is provided from the metalization (11) on the outside.

Abstract: A seismic cable assembly having an acoustically transparent tubular enclosure has at least one hydrophone electrically connected and positioned within the cable assembly enclosure. The hydrophone is made up of a pair of formed, electrically conductive plates that fit against an insulating seal which also forms a fluid seal, providing a sealed chamber defined by the inside surfaces of the conductive plates. A pair of piezoelectric elements are interconnected and positioned within the sealed chamber, one element mechanically and electrically connected to the inside surface of one of the conductive plates and the other piezoelectric element mechanically and electrically connected to the inside surface of the other conductive plate. When pressure is applied to the conductive plates, they deform, causing the piezoelectric elements to flex. When the elements flex, an electrical output is presented on the conductive plates which serve as terminals.

Abstract: A borehole logging system employs a compressional wave transmitter and a shear wave transmitter. The transmitters are alternately fired to impart compressional and shear waves into the formations surrounding the borehole. A bender-type receiver, spaced apart from the transmitter in the borehole is alternately gated so that the voltages across its pair of piezoelectric planar surfaces are subtracted during the expected time period of symmetrical motion of the receiver to provide a compressional wave output and added during the expected arrival time period of unsymmetrical motion of the receiver to provide a shear wave output.

Abstract: This invention is a small light weight underwater transducer that operates at low frequencies. The foregoing is accomplished by embedding piezoelectric material in the wall of an oval shell between the shell's nodal points. When an alternating voltage is applied to the piezoelectric material, the piezoelectric material expands and contracts causing large circumferential strains in the shell of the transducer. The aforementioned strains cause the shell to vibrate and energy to be radiated into the water. This invention may also be used as a receiving type of transducer.

Abstract: A directional transducer is disclosed which includes flexural disc transducer elements mounted by their periphery to an inertial mass and connected to the transducer housing by their centers.