Abstract: A spherical surface acoustic wave apparatus includes a surface acoustic wave propagation substrate which has a surface acoustic wave circulation path on an outer surface thereof. The path is configured to be annular and continuous using at least a part of a spherical shape, and is able to be excited to generate surface acoustic wave and allows the excited surface acoustic wave to propagate and circulate therein in its annular and continuous direction. The apparatus further includes a substrate support which supports a region of the outer surface of the substrate, the region excluding the circulation path, and a support for a surface acoustic wave excitation/detection unit, which supports an elastic member supporting the excitation/detection unit, which makes the excitation/detection unit being in contact with the circulation path of the outer surface of the substrate through the elastic member, and which elastically deforms the elastic member.

Abstract: A source signal is converted into a time-variant temperature field with transduction into mechanical motion. In one embodiment, the conversion of a source signal into the time-variant temperature field is provided by utilizing a micro-fabricated fast response, bolometer-type radio frequency power meter. A resonant-type micromechanical thermal actuator may be utilized for temperature read-out and demodulation.

Abstract: A piezoelectric linear motor for providing enhanced displacement using a dome-shaped piezoelectric ceramic is provided. The piezoelectric linear motor includes a dome-shaped piezoelectric ceramic (100) processed such that different electrodes are formed on opposite surfaces of the piezoelectric ceramic. A vibration shaft (200) is fixed to a first surface of the piezoelectric ceramic so that the vibration shaft moves in conjunction with displacement of the piezoelectric ceramic. A movable element (300) is linearly driven through friction with the vibration shaft while coming into contact with the vibration shaft. The movable element moves in a movement direction of the vibration shaft if the inertial force of the movable element is less than the frictional force between the movable element and the vibration shaft when the vibration shaft moves. According to the present invention, the piezoelectric ceramic is formed in a dome shape, so that movement displacement is enhanced.

Abstract: A flexural-mode tuning-fork type quartz crystal resonator includes a proximal portion, a pair of vibrating arm portions, and a plurality of first concave portions. The vibrating arm portions project in a direction from the proximal portion. The first concave portions are formed into groove shapes in the upper and lower principal surfaces of the proximal portion, and extend in the widthwise direction perpendicular to the longitudinal direction of the pair of vibrating arm portions. The first concave portions formed in the upper principal surface of the proximal portion and those formed in the lower principal surface of the proximal portion are arranged at a predetermined interval not to face each other.

Abstract: A spherical rotary piezoelectric motor comprises a spherical rotor, a hemispherical stator, and a plurality of piezoelectric actuators. The hemispherical stator comprises an inner surface and an outer surface, wherein the inner surface forms a hemispherical hollow portion which substantially corresponds to the spherical rotor so as to contain a portion of the spherical rotor. The plurality of piezoelectric actuators is arranged on the inner surface (or the outer surface) of the hemispherical stator respectively so as to drive the hemispherical stator. The hemispherical stator generates traveling waves with a resultant elliptical motion, so the spherical rotor can be rotated accordingly with at least one degree of freedom.

Abstract: A source signal is converted into a time-variant temperature field with transduction into mechanical motion. In one embodiment, the conversion of a source signal into the time-variant temperature field is provided by utilizing a micro-fabricated fast response, bolometer-type radio frequency power meter. A resonant-type micromechanical thermal actuator may be utilized for temperature read-out and demodulation.

Abstract: A tuning fork resonator element that has a base portion, first and second resonating arms extending from the base portion in a first direction, and a support frame sandwiching the first and second resonating arms and being connected to the base portion includes: a first excitation electrode, formed in an area close to a connection portion with the base portion of the support frame, being connected to a mount electrode with a conductive adhesive; a second excitation electrode, formed in at least one of an area sandwiching the first and second resonating arms of the support frame and an area positioned farther than the first and second resonating arms in the first direction, being connected to a mount electrode with the conductive adhesive; and a cut portion of the support frame formed on an external surface of the support frame.

Abstract: The present invention is intended as a method for producing an electromagnetic transducer of variable reluctance type, where the transducer's seismic mass side and load side are mounted together in a first step while the inner and/or outer air gaps are supplied with shims in order to create balanced air gaps in an axial direction between the bobbin core's arms and the inner and outer yokes, whereupon in a second step the bobbin core is fixed through the side piece to an adapter already attached in a corresponding free moving end of a spring suspension, with compliant properties working in an axial direction and arranged between the seismic mass side and the load side in resting state in order to maintain balanced air gaps when finally, in a third step, the shims are removed and the air gaps are released.

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

Abstract: A piezoelectric transducer formed of a body of piezoelectric material having first and second opposed sides and first and second electrically conductive layers on the first and second sides respectively of the piezoelectric body, wherein the piezoelectric body and the electrically conductive layers are so constructed that they form a plurality of separate adjacent series-connected transducer elements. A method of manufacturing such a transducer is also disclosed. The piezoelectric body may have a substantially uniform direction of polarization, or alternating zones of opposite polarization. The conductive layers may be continuous or discontinuous, together forming isolated electrode pairs to define the individual transducer elements. The elements can be hard wired or connected through a switching circuit to display either circumferential or axial or other ultrasonic focal patterns, and may be connected in a parallel, rather than a series configuration.

Abstract: A filter includes multiple piezoelectric thin-film resonators each having a substrate, a lower electrode formed on the substrate, a piezoelectric film formed on the lower electrode, and an upper electrode provided on the piezoelectric film so that the upper electrode and the lower electrode face each other across the piezoelectric film. The multiple piezoelectric thin-film resonators include a first resonator in which at least a part of an outer curved portion of the piezoelectric film of the first resonator is located further out than an outer curved portion of a region in which the upper electrode and the lower electrode face each other across the piezoelectric film.

Abstract: A piezoelectric thin-film resonator includes a lower electrode formed on a substrate to define a rounded dome-shaped cavity between the lower electrode and the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on the piezoelectric film. A membrane region is an overlapping region of the lower electrode and the upper electrode interposing the piezoelectric film and a projected area of the cavity onto the substrate includes the membrane region.

Abstract: A process for fabricating a ceramic electroactive transducer of a predetermined shape is disclosed. The process comprises the steps of providing a suitably shaped core having an outer surface, attaching a first conductor to the outer surface of the core, coating an inner conductive electrode on the outer surface of the core such that the inner conductive electrode is in electrical communication with the first conductor, coating a ceramic layer onto the inner electrode, thereafter sintering the ceramic layer, coating an outer electrode onto the sintered ceramic layer to produce an outer electrode that is not in electrical communication with the first conductor, and then poling the sintered ceramic layer across the inner electrode and the outer electrode to produce the ceramic electrode.

Abstract: Two similarly shaped, such as rectangular, shells are attached to one another such that they form a resulting thin airfoil-like structure. The resulting device has at least two stable equilibrium shapes. The device can be transformed from one shape to another with a snap-through action. One or more actuators can be used to effect the snap-through; i.e., transform the device from one stable shape to another. Power to the actuators is needed only to transform the device from one shape to another.

Abstract: Laser beam machining is applied to form arbitrarily shaped electroactive ceramics for transducers (e.g., electromechanical sensors and actuators). One particularly preferred embodiment of the invention comprises machining parallel grooves in a ceramic plate to improve flexibility. The grooves provide strain relief in bending by relieving Poisson strains transverse to the direction of bending. This embodiment offers the further benefit that planar anisotropy or directionality is introduced in the transducer. The machining process of the invention further enables the production of more complex geometries than those currently known in the art. Because of the flexibility of the machining process, virtually any desired transducer shape may be produced.

Abstract: The piezo-composite curved actuator of the present invention includes a piezoelectric layer 10, a lightweight fiber-reinforced lower composite layer 20 with a high GTE (coefficient of thermal expansion) and a low modulus, which is placed under the piezoelectric layer, a lightweight fiber-reinforced upper composite layer 30 with a low GTE and a high modulus, which is placed on the piezoelectric layer, and an insulator layer 23 placed between the piezoelectric layer and the upper composite layer. The piezo-composite curved actuator may further include an insulator layer 24 placed on the upper composite layer. Also, the piezo-composite curved actuator may further include insulator layers 22 placed between the insulator layer 23 and the lower composite layer 20 at the both sides of the piezoelectric layer 10.

Abstract: Laser beam machining is applied to form arbitrarily shaped electroactive ceramics for transducers (e.g., electromechanical sensors and actuators). One particularly preferred embodiment of the invention comprises machining parallel grooves in a ceramic plate to improve flexibility. The grooves provide strain relief in bending by relieving Poisson strains transverse to the direction of bending. This embodiment offers the further benefit that planar anisotropy or directionality is introduced in the transducer. The machining process of the invention further enables the production of more complex geometries than those currently known in the art. Because of the flexibility of the machining process, virtually any desired transducer shape may be produced.

Abstract: An immunoassay, e.g. ELISA, method and kit for determining (preferably quantitatively) an analyte adsorbed at a surface or present in a liquid sample, comprising binding the analyte to a solid phase, attaching a marker to the analyte, and detecting marker attached to the solid-phase. The invention proposes to use a combination of marker and detection (e.g. an enzyme-substrate combination) which is capable of producing a precipitate on a solid phase which carries the marker and to detect the binding of analyte to the solid phase by in-situ determining the change in surface mass of the solid phase due to the formation of the precipitate. Ellipsometry is an example of a technique suitable for determining the change of surface mass of the solid phase, which could be made of a silicon- or chromium-sputtered glass slide The invention shortens the assay time and/or improves the assay sensitivity, and allows to measure extremely low surface concentrations of analytes of interest.

Abstract: A process for fabricating a ceramic electroactive transducer of a predetermined shape is disclosed. The process comprises the steps of providing a suitably shaped core having an outer surface, attaching a first conductor to the outer surface of the core, coating an inner conductive electrode on the the outer surface of the core such that the inner conductive electrode is in electrical communication with the first conductor, coating a ceramic layer onto the inner electrode, thereafter sintering the ceramic layer, coating an outer electrode onto the sintered ceramic layer to produce an outer electrode that is not in electrical communication with the first conductor, and then poling the sintered ceramic layer across the inner electrode and the outer electrode to produce the ceramic electrode.

Abstract: A pressure- and temperature-sensitive transducer comprises a tubular housing, a resonator located within the housing and end caps closing the ends of the housing. The resonator is located in a radial plane with respect to the housing and is connected to the housing by two separate connecting regions. The housing, resonator and connecting, regions are formed from a single piece of double rotation cut quartz. The shape, dimensions and position of the connecting regions is chosen to optimize stress in an axis responsive to changes in pressure and temperature while minimizing stress in an axis responsive predominantly to pressure.

Abstract: A curved piezoelectric device is attached to a plate to vibrate the plate. Mass-loading is applied to at least one free end of the piezoelectric device to increase output.

Abstract: A micro-shell transducer includes a substrate; an electro-active medium mounted on the substrate and including an arched section spaced from the substrate defining a chamber between the substrate and arched section; and a pair of electrodes mounted on the medium for either applying an electric field across the medium for flexing the arched section or sensing the electric field generated by a flexure of the medium.

Abstract: An electroactive device incorporating the invention is configured from an electroactive ceramic hollow sphere having an inner surface, an outer surface, a wall thickness aspect and a radius aspect. Conductive electrodes are positioned on opposed surfaces of said sphere and conductors enable application of an electrical potential between the conductive electrodes to enable a field to be applied to said sphere that causes a dimension change in the radius aspect and thickness aspect thereof. In one embodiment the sphere has a d33 direction parallel to the thickness aspect, and d31 & d32 directions parallel to the sphere surfaces and in another embodiment the d33 direction is perpendicular to the thickness aspect, and d31 & d32 directions are respectively parallel and perpendicular to the sphere surfaces. The sphere is preferably supported by a rod that either passes throng one opening in the sphere or through two opposed openings. Further, the rod may include a pathway for other instrumentality's.

Abstract: A piezoelectric vibrator using thickness mode as the primary vibration and having a cross section of a bevel or convex configuration is provided which is superior in mechanical strength, easy to steadily mount, and has a small dispersion of characteristic. By employing a structure in which a vibrator 1 and a support section 2 are composed of the same material, the end portions of the vibrator section are integrated with the support section on the periphery of the vibrator, and the configuration of the cross section of the vibrator 1 is such that the thicknesses of the end portions of the vibrator are smaller than that of the central portion of the vibrator, a superior mechanical strength without chipping or cracking at the end portions of the vibrator is obtained allowing easy mounting while keeping the vibrator size small.

Abstract: A dual-mode thickness-shear quartz pressure transducer includes a unitary piezoelectric crystal resonator and cylindrical housing structure wherein the resonator is located on a median radial plane of the housing and the exterior of the housing is provided with a pair of parallel flat surfaces which are located at an angle relative to the X" axis of the resonator. According to the presently preferred embodiment, the transducer is made from an SC-cut or a WAD-cut solid quartz crystal cylinder which is ultrasonically milled to form a plano-convex or bi-convex resonator disk in the medial radial plane of a hollow cylinder and the pair of exterior flats. The wall thickness of the cylinder is altered at the location of the flats such that stresses at the center of the resonator disk are anisotropic.

Abstract: A shape formed multi-laminate transducer which conforms to nonlinear dependent shaped geometries and the shape forming process for producing the nonlinear dependent shaped multilaminate transducer is presented. The shape forming process includes the cutting of the tape cast material to a predetermined two-dimensional shape and then pressing the cut material to form the desired three-dimensional nonlinear dependent shape. After shape forming, the sample is sintered, metalized, poled, and made into an acoustical device such as a transducer. The production of such a device by using tape cast material allows designers to easily vary the shape of the product as well as to be able to vary the properties within simply by exploiting the lamination method associated with tape casting. As such, a designer is able to design and manufacture a transducer optimized to meet the requirements of a particular application.

Abstract: A transducer array is constructed from a constant arc length portion of a ght circular cylindrical shell of piezoelectric transduction material. The constant arc length portion is segmented evenly along the length thereof to define a plurality of transducers. The transducers can be in the free field or mounted on a planar baffle.

Abstract: A flexible layer of piezoelectric material, e.g., a known PVDF polymer, is used for generating electrical energy for use on a water craft. In one arrangement, the sheet is laminated within a craft hull of fiberglass. Electrodes are provided for the major opposite surfaces of the layer, and an encapsulating material, e.g., fiberglass or a layer of the polymer itself, comprises the water contacting, exterior surface of the hull. In salt water, the water is one electrode, and an outer encapsulating layer is omitted. Spaced apart air pockets are optionally provided along the polymer sheet for increasing the flexing thereof in response to passing water and for inducing turbulence in the passing water. Elongated, flexible and electroded sheets, optionally including air pockets, are towed behind or beneath the craft, or are flown from a mast on the craft.

Abstract: Monolithic, internally asymmetrically stress biased electrically active ceramic devices and a method for making same is disclosed. The first step in the method of the present invention is to fabricate a ceramic element having first and second opposing surfaces. Next, only the first surface is chemically reduced by heat treatment in a reducing atmosphere. This produces a concave shaped, internally asymmetrically stress biased ceramic element and an electrically conducting, chemically reduced layer on the first surface which serves as one of the electrodes of the device. Another electrode can be deposited on the second surface to complete the device. In another embodiment of the present invention two dome shaped ceramic devices can be placed together to form a completed clamshell structure or an accordion type structure. In a further embodiment, the clamshell or accordion type structures can be placed on top of one another.

Abstract: The temperature of a quartz crystal oscillator is determined by comparison of a pair of inharmonically related overtone oxcillations of the same vibrational type, e.g. a thickness shear mode, and of the same overtone order. The use of inharmonically related signals relaxes the contraints on crystal design. The technique may be employed in a crystal controlled frequency synthesizer to provide a feedback signal for maintaining constant output frequency.

Abstract: In order to make a probe having a concave attack face, a continuous acoustic transition blade (5) is used. Said blade is metallized (7) and is common contact with all the front metallizations (6) of the piezoelectric elements of the probe. The rear metallizations (8) of the elements terminate electrically and independently backwards of the probe. As a result, the electric connection of the piezoelectric elements is simplified. Said probe is usable in experiments with ultrsounds where good focusing is desired.

Abstract: A method for providing a curved composite ultrasound transducer of a relatively large size. A blank of piezoceramic material has its rear side reticulated with a series of relatively coarse grooves. The front side of the material is reticulated with a series of relatively deep fine grooves to provide a matrix of upstanding piezoceramic rods. The spaces between the rods on the front side of the blank are therefore filled with a curable polymeric resin (epoxy). The resin filling the blank spaces on the front side is partially cured. After partial curing, the blank is placed into a spherical compression mold and molded so that its front side is formed concave and its rear side convex. The resin is cured while holding the molded blank under pressure in the mold until the resin has cured. After curing, the blank is removed from the mold and the back side is ground away to provide a spherically curved transducer having a multiplicity of individual piezoceramic rods disposed in a matrix of cured resin.

Abstract: A dark field ultrasonic transducer is constructed with an outer annular spherical or conical transducer element and an inner spherical element. The outer annular element is excited and insonifies a small portion of a part surface near a discontinuity or crack with longitudinal waves or with surface waves. The inner dark field element is not focused to be sensitive to either reflected sound or waves reradiated from the surface waves, but detects sound scattered from surface discontinuities such as a crack edge. When surface waves strike a crack edge and restrike it after reflection from the bottom of the crack, two pulses are received and the time delay between them is a measure of crack depth. The crack shape and crack depth profile are determined as the part is scanned. A sphere-cone transducer, the preferred embodiment, is fabricated by stretching thin piezoelectric polymer film over a tool having a ball embedded in a conical surface.

Abstract: The output surface of an acoustic printhead having one or more concave acoustic beam forming devices for supplying focused acoustic beams to eject droplets of ink on demand from the surface of a pool of ink is planarized by filling those concave devices with a solid material having an acoustic impedance and an acoustic velocity which are intermediate the acoustic impedance and the acoustic velocity, respectively, of the ink and of the printhead. This not only facilitates the cleaning of the printhead, but also eliminates the edges upon which an optional ink transport or the like may tend to drag. The outer surface of the filler may be essentially flush with the face of the printhead, or the filler may overcoat the printhead.

Abstract: The ink ejecting portion of an ink jet printer is described, wherein a single ceramic transducer is used to create the pressure for the ink droplets. Unlike prior devices, the transducer is a one-piece member as opposed to use of a crystal and diaphragm. The one-piece member is practical because of the generally spherical configuration of the crystal.

Abstract: A loudspeaker primarily for the high frequency audio region includes a driving device coupled to a diaphragm of convex outer configuration and extending over more than 180.degree. spherical angle. The driving device changes the distance between the two coupling areas of the diaphragm under the action of an electrical signal applied thereto. Elastic deformations appear on the diaphragm which give rise to an emission of soundwaves.

Abstract: A liquid drop emitter utilizing acoustical principles ejects liquid from a body of liquid onto a moving document to form characters or bar codes thereon.

Abstract: There is disclosed an ultrasonic piezoelectric transducer consisting of two separate transducer elements bonded together. The individual elements may be similar or different in size, thickness, and/or material. The material which bonds the two elements together may serve as one electrode, and two other electrodes coat the outer surfaces of the two individual elements. By switching the electrodes which are connected to the transmit and receive circuits of an ultrasonic medical scanning apparatus, the single transducer may be used for imaging with high resolution at one frequency, and for pulse Doppler velocity measurements at a different frequency. The two elements may be driven individually or in combination, in order to achieve different operating frequencies and focusings.

Abstract: A piezoelectric resonator comprises a crystal having an outer peripheral portion connected to a central portion by an intermediate zone which is short in the radial direction, is hollowed out over its major part and has at least two connector bridges between the outer and central portions. Electrodes are arranged facing one of the main portions of the crystal which then forms the vibrating portion of the resonator. The non-vibrating main portion serves as a support for the crystal. The surfaces of the connector bridges are continuous with the corresponding surfaces of the vibrating portion.

Abstract: An electroacoustic transducer having high acoustic-to-electric energy conversion per unit volume. The transducer is in the form of a body having a cylindrical central section and hemispherical end sections, the central section and the end sections formed from active piezoelectric material and electrically interconnected with respect to a pair of output terminals wherein the polarizations of the central section and the end sections are arranged to convert acoustic pressure on the entire external surface area of said body to be effective in producing electrical energy. The physical parameters of each section are matched to produce essentially equal electrical characteristics of each section to form an inherently symmetrical transducer. The transducer has high sensitivity for a small size and is especially adapted for use in thin line towed arrays. The symmetrical form, polarities and balanced connections of the transducer provide cancellation of forces due to acceleration.

Abstract: A piezoelectric crystal has a concave active surface and a high acoustical impedance. A flat layer of molded material having a low acoustical impedance faces the active surface of the crystal to form a space therebetween. An intermediate layer of molded material having an intermediate acoustical impedance fills the space between the crystal and the flat layer. Preferably, the intermediate material has a sonic velocity near that of water, and the flat layer has a uniform thickness of approximately 1/4 of the average wavelength of the ultrasonic energy emitted by the crystal. A housing supports the crystal, the flat layer, and the intermediate layer.

Abstract: A modulator for the generation of uniform liquid drops over a wide bandwidth of drop rates is provided. The concave and convex surfaces of a hemispherical piezoelectric crystal are electroded, and the transducer formed thereby is seated within and bonded to the wall of a concave well in the face of a solid epoxy crystal backing. A ring gasket is placed contiguous to the ring shaped edge of the transducer, and a nozzle plate is placed in sealed relation with the ring gasket to form a liquid chamber between the plate and the transducer. The physical dimensions of the component parts of the modulator are made smaller than the half wavelength of the shortest standing acoustical wave that can be established at the highest of the operable drop frequency rates in a structure of the same material as the part in question.