Abstract: A method for making a diaphragm unit of a condenser microphone includes the steps of: forming a liftoff layer on a substrate; forming an insulator diaphragm film on the liftoff layer; and removing the liftoff layer from the diaphragm film and the substrate so as to separate the diaphragm film from the substrate.

Abstract: An ultrasonic monitoring system is formed with a probe unit. In one example an array of transducer cells is arranged in rows and columns formed along a first plane with a first pitch along a first direction. An integrated circuit including an array of circuit cells is formed along a second plane parallel to the first plane. The circuit cells are spaced apart along the first direction at a second pitch smaller than the first pitch. A first of the transducer cells is vertically aligned, along a direction normal to one of the planes, with a first of the circuit cells and having a connection thereto. A second of the transducer cells is offset from vertical alignment with respect to the position of a second circuit cell so as to not overlie the second circuit cell.

Abstract: A method for making condenser microphones includes: forming a fixed electrode layer structure of a plurality of fixed electrode units; forming a sacrificial layer of a plurality of sacrificial units on one side of the fixed electrode layer structure; forming a diaphragm layer structure of a plurality of diaphragm units on the sacrificial layer; forming a patterned mask layer on an opposite side of the fixed electrode layer structure opposite to the sacrificial layer; forming a plurality of etching channels, each of which extends through the patterned mask layer and the fixed electrode layer structure; removing a portion of the sacrificial layer of each of the sacrificial units so as to form a spacer between a respective one of the fixed electrode units and a respective one of the diaphragm units; and removing the patterned mask layer.

Abstract: The present invention, in one set of embodiments, provides methods and systems for integrating conducting diamond electrodes into a high power acoustic resonator. More specifically, but not by way of limitation, in certain embodiments of the present invention, diamond electrodes may be integrated into a high power acoustic resonator to provide a robust sensing device that may provide for acoustic cleaning of the electrodes and increasing the rate of mass transport to the diamond electrodes. The diamond electrodes may be used as working, reference or counter electrodes or a combination of two or more of such electrodes. In certain aspects, the high power acoustic resonator may include an acoustic horn for focusing acoustic energy and the diamond electrodes may be coupled with the acoustic horn.

Abstract: A back plate having a stationary back electrode is secured to a substrate. A diaphragm electrode is mounted on the back plate interposing a spacer. A frame having a sound collecting hole is mounted on the diaphragm electrode.

Abstract: A microphone is constructed to be more tolerant to a wide range of relative humidity conditions without adversely affecting the performance of the microphone. The microphone includes a housing with a sound port for receiving sound and an electret assembly for converting the sound into an output signal. The electret assembly includes a diaphragm and a backplate. The backplate is made of at least two layers, usually polymeric layers. The first layer of material has a first hygroscopic coefficient and a second layer of material has a second hygroscopic coefficient. The first and second layers cause the backplate to bend in response to higher humidity conditions, thereby minimizing the adverse effects on microphone performance caused by characteristic changes in the diaphragm at the higher humidity conditions.

Abstract: A pixel array device is fabricated by a laser micro-milling method under strict process control conditions. The device has an array of pixels bonded together with an adhesive filling the grooves between adjacent pixels. The array is fabricated by moving a substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth. The substrate is of an ultrasonic transducer material in one example for fabrication of a 2D ultrasonic phase array transducer. A substrate of phosphor material is used to fabricate an X-ray focal plane array detector.

Abstract: An electromechanic film intended for transforming electric energy into mechanical energy and transforming mechanical energy into electric energy. The film (1) is dielectric and formed of cells (3), the ratio of the height and width of which cells is between 3:1 and 1:3. By joining two such films together and controlling them in such a way that in the first film (1) the electric field strength decreases and in the second film (1) the electric field strength increases, a bending acoustic element is provided.

Abstract: A pixel array device is fabricated by a laser micro-milling method under strict process control conditions. The device has an array of pixels bonded together with an adhesive filling the grooves between adjacent pixels. The array is fabricated by moving a substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth. The substrate is of an ultrasonic transducer material in one example for fabrication of a 2D ultrasonic phase array transducer. A substrate of phosphor material is used to fabricate an X-ray focal plane array detector.

Abstract: A back plate having a stationary back electrode is secured to a substrate. A diaphragm electrode is mounted on the back plate interposing a spacer. A frame having a sound collecting hole is mounted on the diaphragm electrode.

Abstract: The preferred embodiments described herein provide an improved ultrasound transducer and method of manufacture thereof. In one preferred embodiment, a method of manufacturing an ultrasound transducer is provided comprising the acts of supporting a layer of piezoelectric material with a window and separating the layer of piezoelectric material into at least two elements by dicing through the layer of piezoelectric material and at least partially into the window. In another preferred embodiment, an ultrasound transducer is provided comprising a first transducer element, a second transducer element, and a window coupled with the first and second transducer elements and comprising a kerf positioned between the first and second transducer elements.

Abstract: A piezoelectric ceramic composition for a surface acoustic wave device which can improve the electromechanical coupling coefficient is provided. The piezoelectric ceramic composition for a surface acoustic wave device is represented by the formula PbaZrxTiy(NimMnnNb⅔)zO3, wherein x+y+z=1, 0.93≦a≦1.02, 0.32≦x≦0.50, 0.41≦y≦0.54, 0.03≦z≦0.21 and 0.24≦m+n≦0.67.

Abstract: A method of detecting precursor seismic electromagnetic waveforms and predicting future seismic activity in the form of an earthquake by placing a detector including a dielectric material in contact with the earth. The detector receives at the dielectric material precursor seismic electromagnetic waveforms traveling within the earth emanating from a region of seismic activity. A sensor responsive to the dielectric material senses a series of individual discrete signals imposed by the waveforms at the dielectric material wherein each of the signals has the characteristic of a rise time that is shorter than its fall time. Alternatively, the discrete signals may be a single discrete signal characterized by a plurality of overlapping waveforms. Then predicting based on the series of the signals the occurrence of the earthquake.

Abstract: Disclosed is a three-dimensional radar apparatus comprising a radar transmitting/receiving unit, a three-dimensional polygon-generating unit, and a three-dimensional graphics unit, wherein a radar transmitter/receiver outputs signals concerning orientation information, distance information, and reception intensity information on the basis of a radio wave reflected from a target, and a scan converter is used to convert the signals concerning the orientation information, the distance information, and the reception intensity information into two-dimensional radar image data composed of two-dimensional rectangular coordinates and brightness information of each of picture elements. The two-dimensional radar image data is also inputted into the three-dimensional polygon-generating unit to perform polygon-generating processing on the basis of the two-dimensional rectangular coordinates and the brightness information of each of the picture elements.

Abstract: A method of detecting precursor seismic electromagnetic waveforms and predicting future seismic activity in the form of an earthquake by placing a detector including a dielectric material in contact with the earth. The detector receives at the dielectric material precursor seismic electromagnetic waveforms traveling within the earth emanating from a region of seismic activity. A sensor responsive to the dielectric material senses a series of individual discrete signals imposed by the waveforms at the dielectric material wherein each of the signals has the characteristic of a rise time that is shorter than its fall time. Alternatively, the discrete signals may be a single discrete signal characterized by a plurality of overlapping waveforms. Then predicting based on the series of the signals the occurrence of the earthquake.

Abstract: An acceleration sensor is based on a semiconductor technique which is suitable for mass production. The resulting acceleration sensor is small in size and high in precision. The acceleration sensor includes a stationary section, an acting section to which a force is applied in response to acceleration, a flexible section through which the stationary section is coupled to the acting section, a plurality of distortion sensing elements coupled to the flexible section, a first weight having a bottomed hole which is gradually smaller in width towards the bottom of the hole, the first weight being coupled to the acting section and a second weight, greater in specific gravity than the first weight, coupled to the bottom of the hole of the first weight.

Abstract: A method of detecting precursor seismic electromagnetic waveforms and predicting future seismic activity in the form of an earthquake by placing a detector including a dielectric material in contact with the earth. The detector receives at the dielectric material precursor seismic electromagnetic waveforms traveling within the earth emanating from a region of seismic activity. A sensor responsive to the dielectric material senses a series of individual discrete signals imposed by the waveforms at the dielectric material wherein each of the signals has the characteristic of a rise time that is shorter than its fall time. Alternatively, the discrete signals may be a single discrete signal characterized by a plurality of overlapping waveforms. Then predicting based on the series of the signals the occurrence of the earthquake.

Abstract: An improved invasive acoustic sensor apparatus detects particulate matter in a flow by impingement thereon. The apparatus includes an axially extending probe body having an active length positionable in a flow and a distributed piezoelectric transducer disposed therein. The transducer is acoustically coupled to an interior surface of the body, along substantially the entire active length thereof, and may be a piezoelectric film, piezoelectric tube, or a plurality of electrically parallel connected piezoelectric tube elements. The apparatus further includes an acoustic isolation layer disposed between the probe body and positioning structure to reduce transmission of process wall vibration to the transducer.

Abstract: A device and a method for locating and counting insects in agricultural commodities has been developed. Acoustic sensors pick up sounds emanating from adult and or larval insects. The electrical outputs of the sensors are amplified and analyzed to determine (1) the first sensor to detect the sound, (2) the second sensor to detect the sound and (3) the time difference between the first and second detection. These determinations are used to calculate the locations and numbers of insects in the agricultural commodity samples.

Abstract: A self-orienting seismic detector for detecting vertical acceleration regardless of the device's horizontal orientation. The detector comprises a housing fitted with diaphragms capable of generating signals. A mass is internally suspended within the housing between the diaphragms by means of a filament which is connected at each of its ends to one of the diaphragms. Vertical motion of the detector causes internal displacement of the mass within the housing. Motion by the mass within the cylinder is translated by the filament to the diaphragms which generate signals which may then be recorded. The detector may be incorporated within or attached to an undersea cable to form a seismic detection system primarily suitable for placement on an ocean bottom, but which may be employed in a towed array. In a primary embodiment, the detector is sealed from external pressure changes such that the stresses placed upon the detector's diaphragms will be governed by particle acceleration changes rather than pressure changes.

Abstract: In a preferred embodiment, an accelerometer sensor system, including: a housing structure; a first acceleration sensor disposed in the housing structure at a first selected location along the vertical axis of the housing structure, the first acceleration sensor providing a first output; a second acceleration sensor disposed in the housing structure at a second selected location along the vertical axis, the second acceleration sensor providing a second output; and apparatus to combine the first and second outputs of the first and second acceleration sensors such as to simulate the output from a virtual acceleration sensor located at any selected location on the vertical axis, allowing one to reduce noise induced by pitch motion, at any desired frequency or across a desired frequency band.

Abstract: The invention relates to a method for manufacturing an acoustic sensor, and also to the sensor. The sensor comprises a piezoelectric sheet (12) mounted on a support (14) and electrically connected to electrodes (16,18) connected by electrical conductors (20,22) to a measurement device, characterized in that the assembly constituted by the sheet (12) and its support (14) is coated with a one-piece polymerizable coating layer (24) which is preferably electrically insulating, such that the portion (24a) of the coating layer (24) overlying the sheet (12) constitutes a protective layer which is rendered non-detachable or essentially non-detachable from the piezoelectric sheet (12). The method for manufacturing this sensor is extremely simple and inexpensive, and the protective layer is non-detachable.

Abstract: In a preferred embodiment, an accelerometer sensor system, having a first axis of rotation at a first given frequency of periodic oscillation thereabout, which accelerometer sensor includes: a first acceleration sensor; a platform to which the first acceleration sensor is fixedly attached; and the first acceleration sensor being vertically displaced from the first axis of rotation by a first selected distance such that the noise received by the first acceleration sensor, due to the periodic oscillation at the first frequency, is reduced.

Abstract: A piezo-electric flexible membrane is formed by treating a perfluorinated membrane in order to produce a membrane having an electrical resistance greater than 1.times.10.sup.9 ohms. The resultant piezo-electric membrane may be used as an ultrasound transducer.

Abstract: An acoustic field transducer (10) comprises an elastic membrane (15A) made of piezo-electric material and peripherally held in stretched condition with static strain. A major surface area of the membrane (15A) is free to move in response to acoustic field variations which are coupled to the membrane (15A). Electrical conductors (17) are connected to the membrane (15A) for collecting signals piezo-electrically generated by the membrane due to strain variations and which are a measure of the acoustic field variations. The acoustic field variations are coupled to the membrane (15A) in a variety of different arrangements.

Abstract: A self-orienting vertically sensitive accelerometer is disclosed for measuring a vertical component of acceleration independently of the orientation of the accelerometer. The accelerometer of the present invention includes a spherical plastic shell having a plurality of perforations disposed therein and a thin film of metallic coated piezoelectric polymer bonded to the exterior thereof, forming a small diaphragm at each perforation. In response to acceleration a dynamic pressure is developed within a fluid mass partially filling the spherical plastic shell which creates a strain and resultant charge in each small diaphragm of piezoelectric polymer. The vast difference in density between the fluid mass and the air in the remaining volume of the spherical plastic shell permits the charge developed in each small diaphragm under fluid pressure to be attributed solely to the vertical component of acceleration applied to the fluid mass.

Abstract: Detection of insect infestation in an agricultural commodity is provided by piezoelectric means for generating electricity in response to vibration only of a frequency above about 500 Hertz, in vibrational communication with the agricultural commodity. The present invention may be utilized to detect infestation by a variety of different insects such as rice weevil, lesser grain borer, angoumais moth, in numerous types of agricultural commodities including corn, wheat, rice nuts, cotton, etc.. Various embodiments are disclosed including use of the piezoelectric means, on a probe, with a sample cup, in a device for telemetry, and with various container means for containing an agricultural commodity including e.g. a truck, ship, railroad car and storage bin such as a silo or grain elevator.

Abstract: An accelerometer-based direction finding and ranging transducer such as a hydrophone uses piezoelectric ceramic as the active material. Orthogonally arranged accelerometers share an inertial mass and resonance control system and the accelerometers together with a pressure hydrophone and electronics are all housed within one pressure vessel.

Abstract: An echographic technique based method for prospecting of the subsoil or sea bottom and the like, by means of acoustic waves and carried out by the use of an apparatus constitued, in combination of a known acoustic wave transmitting equipment (1) comprising of a body (6, 8) in the inside of which a chamber (9) is formed defined by an internal reflecting surface (7) shaped like a round paraboloid of axis (Y--Y), closed at the base by an elastic diaphragm (5) and filled with a proper liquid, into which acoustic waves are emitted produced by a pair of main electrodes (10a, 10b) associated with an auxiliary discharge priming electrode (11) put between the first ones.

Abstract: An accelerometer for blast monitoring comprises at least one piezoelectric transducer having a piezoelectric membrane attached along the edge thereof to the sidewall of a suitable container and mounted for free movement in such container for generating a high impedance electrical output signal upon deformation of the piezoelectric membrance by vibration during a blast, a high to low impedance converter connected to the piezoelectric membrane for converting the high output impedance of the piezoelectric membrane into a low impedance signal for transmission through long cables to recording equipment, and means for encapsulating the piezoelectric transducer and converter into epoxy or other solid material to minimize response of the transducer to surrounding acoustic signals.

Abstract: A piezoelectric transducer assembly for producing sonar signals for transmission underwater and for detecting reflected sonar signals. The assembly includes a two-dimensional generally planar array of piezoelectric elements disposed in an elastomer casing. The elements are coupled by way of conductors to electronic circuitry which produces electrical signals for stressing the piezoelectric elements and which processes electrical signals produced by the piezoelectric element in response to reflected sonar signals. The piezoelectric elements are closely packed and are selected to have low cross-coupling characteristics. At least some of the elements are oriented so that their axes of polarization are generally perpendicular to the plane of the array.

Abstract: In an acoustic ground vibration detector for the detection of infrasound ground vibrations, comprising at least one three-component geophone probe, the three individual geophones of said geophone probe are electrically connected in series and act upon an operation amplifier whose output signal activates a Reed relay. The activated Reed relay switches on a sound signal transmitter which produces an audible acoustic signal for the duration of the ground vibration signal. The acoustic ground vibration detector is intended in particular for locating buried persons. Moreover, it serves to protect important objects by registering infrasound ground vibrations produced by footfall sound.

Abstract: A geophone designed to measure the vibrations of bodies, especially vibrations in the earth's crust, comprises two-strip sensors made of piezoelectric polymer, embedded by one end in the geophone casing and resting freely, by one side, on the inertial mass of the geophone, thus enabling the making of geophones with a very wide pass-band.

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 piezoelectric transducer in which a casing is mounted in a sealing manner on a base member for supporting two rod-shaped terminals, a piezoelectric element is bonded to the inner surface of said casing, and electrodes on the front and back surfaces of said piezoelectric element are electrically connected to said terminals. The transducer is supported at the position of a node of the free oscillation mode or the forced oscillation mode. The interior of the casing in the transducer is filled with nitrogen gas.

Abstract: An ultrasonic transducer comprises a diaphragm formed by a metal plate provided with a bulged portion in its center and a piezoelectric element bonded to the inner surface of the bulged portion thereby to make the diaphragm vibrate in a bending mode. A node line is present outside the bulged portion in vibration of the diaphragm, and the diaphragm is sandwiched by first and second elastic members along the node line. The first and second elastic members are held between a case and a base fixed thereto so that the diaphragm is elastically retained through the first and second elastic members.

Abstract: The preferred embodiment of this invention includes a logging sonde, an elongated pair of oppositely polarized piezoelectric plates connected to each other by their flat surfaces, and an electrical pulse applying means for applying electrical pulses across the pair of plates so as to bend and vibrate the plates in a direction perpendicular to the length of the plates. Vibration of the plates in a fluid contained in a well creates in the fluid a positive compressional wave in one direction and simultaneously a negative compressional wave in the opposite direction. The two compressional waves will interfere to produce a dipole shear wave in the earth surrounding the well. The dipole shear wave arrival is detected at two locations in the fluid spaced longitudinally along the well from each other and from the plate.

Abstract: For use in an acoustic logging tool having a sonde adapted to be lowered in a borehole, an improved acoustic transducer comprising a pyramidal frustrum is disclosed. The preferred embodiment incorporates fifteen sides. Each side mounts a piezoelectric crystal for receiving. Mechanical resonant frequencies of the transducer are outside the receiver band width which is about 25 kHz. The resonant frequencies are above 25 kHz, thereby avoiding primary resonant frequencies within the band width.

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: A method for manufacturing a compound accelerometer that is maximally sensitive to a desired acceleration vector to the exclusion of orthogonal vectors. The compound accelerometer is made by combining two simple accelerometer units. The simple accelerometer units consist of a hollow container closed at each end by a piezo-electric transducer. The two transducers are oppositely polarized and are selected to have a desired combined series capacitance value. The container is partially filled with a volume of heavy liquid and the accelerometer is excited. During excitation, the output voltage is continuously measured and the volume of liquid is microadjusted until the output voltage equals a prescribed level. The outputs of the individual transducers are measured, the residual voltage difference is tabulated and the dominant transducer is identified.

Abstract: A frequency independent log periodic acoustic device is utilized for the transmission or reception of underwater sound. The acoustic device when used in conjunction with any substantially plane wave receiving or transmitting transducer produces a directional, substantially constant beamwidth diffraction pattern for radiation or reception of underwater sound signals. A key element of the device is a particularly shaped plate or diaphragm, called a filter plate, made of stainless steel or other material having suitable acoustic properties. The filter plate on being placed in front of any plane wave receiving or transmitting transducer acts automatically to make the beamwidth of the diffraction pattern of the combined device constant, regardless of frequency. This is achieved by automatically making the effective aperture diameter of the filter plate-transducer combination a constant multiple of the acoustic wavelength of the sound in the underwater medium.

Abstract: The seismic method comprises in one preferred embodiment, towing a long, flexible member over the earth's surface, the member having liquid-filled geophones mounted thereon or coupled thereto and suitably spaced therealong, and a seismic cable for receiving the individual outputs of the geophones. Each liquid-filled geophone provides an output electric signal having a polarity corresponding to the direction of the earth's motion. In another embodiment of the method of this invention, the geophones are positioned on the earth's surface in a predetermined pattern; their output signals are transmitted to a utilization device; then the geophones are moved to another location, and the detection process is repeated.In a simplified embodiment, the geophone comprises a hollow cylindrical casing defining a chamber therein. A high-density liquid substantially fills the chamber. The chamber has a flexible bottom wall which constitutes a force or pressure transducer.

Abstract: Probe method and means are disclosed for guiding and positioning a robot-actuated tool, such as a gripper or a welding head, through at least one transceiver for generating and sensing focused shockwaves, the probe being associated with the tool for relative movement with respect to the object or objects being sensed, without physically contacting the same.

Abstract: A listening device for pinpointing water leakages, which includes a manually operated rod having a handle at one end for manually positioning of the listening device. An acoustic pick-up apparatus is mounted on the other end of the rod, and it comprises a ceramic audio tone transducer which is operatively connected to an amplifier-receiver which has a level meter on which visual leak signals may be seen. The acoustic pick-up apparatus is also connected to a head phone set to allow hearing of the leaks. The transducer includes a brass diaphragm directly attached to a threaded stud for mounting in the rod.

Abstract: For use in transmitting acoustic waves propated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting a resonant operation in the desired low frequency range.

Abstract: The acoustic data communication system includes an acoustic transmitter and receiver wherein low frequency acoustic waves, propagating in relatively loss free manner in well drilling string piping, are efficiently coupled to the drill string and propagate at levels competitive with the levels of noise generated by drilling machinery also present in the drill string. The transmitting transducer incorporates a mass-spring piezoelectric transmitter and amplifier combination that permits self-oscillating resonant operation in the desired low frequency range.

Abstract: Electroacoustical transmitting or receiving transducer comprising a flat disc piezoelectric transducer element aligned with a conical reflector. The disc transducer element is positioned to transmit acoustic energy in a direction parallel with a borehole axis and this energy is reflected by the conical reflector so that it impinges upon a borehole wall near the critical angle to provide maximum propagation of energy in the rock in one direction parallel to the borehole. The same transducer arrangement also functions as an efficient directional receiver of acoustic energy.

Abstract: A single acoustic filter plate-lens unit for providing directional, frequy independent beam-forming. The unit comprises a liquid container having a curved and radially tapered stainless steel plate on one side and thin metallic shell on the other. An acoustically slow liquid fills the space between the plates. The unit can be used in conjunction with a retina transducer system for conversion of acoustic signals into electrical signals and vice versa.

Abstract: The system is a remotely operated, autonomous multi-channel time history recording device which uses digital and computer technologies to detect, record and display the results of tests that are time varying dependent. It is particularly suited to monitoring the effects of exploding warheads. By placing a series of piezoelectric detectors in an exploding shock wave field, it is possible to ascertain the wavefront propagation. A dynamic peak detector is used is used with each piezoelectric detector to detect the exact peak of the unknown pulse which peak defines the "time-of-arrival" of the pulse. By controlling the system with a computer program it is possible to display the complete time history of the propagating shock wave. When the exploding device is detonated a counter increments in 100 ns steps with its output on a timing bus.