Abstract: A base of piezoelectrically active material having a plurality of spaced apart reflectors formed thereon and transducers positioned between at least some of said adjacent reflectors to produce standing waves at a predetermined frequency, the reflectors between transducers being formed with less than one hundred percent reflectivity so that energy from a standing wave between a pair of adjacent reflectors is coupled through the system to other pairs of reflectors for producing standing waves therebetween. The transducers may operate as electrical energy inputs or as taps to remove energy from the system.

Abstract: This invention relates to improvements of a piezoelectric acoustic device used for a warning buzzer, general buzzer, etc. The conventional piezoelectric acoustic device generates relatively small sound volume, and has disadvantages not sufficiently used practically. This invention contemplates to eliminate this disadvantage, and has a feature that a composite plate for generating a sound is supported in a casing having an opening provided in the direction of thickness, i.e. direction of sound propagation, of the composite plate, and a reflecting plate for reflecting the sound is provided at the rear surface side. Another feature of the present invention is that the above reflecting plate is formed in horn shape to further amplify the generated sound. This invention thus provides an acoustic device for generating large volume with compact structure and less power of consumption.

Abstract: A flexural mode quartz crystal vibrator formed from a quartz crystal plate having first and second opposed substantially planar surfaces, with a plurality of electrodes on at least one side thereof, is provided. The vibrator is characterized by the placement of electrodes on at least one of the opposed surfaces of the quartz crystal plate, the placement of the electrodes providing a vibrator having a thickness of 0.5 mm or less.

Abstract: A piezoelectric tuning fork microresonator advantageously is mounted in a package having a transparent region through which the microresonator can be tuned using a laser beam selectively to remove portions of weights provided on the tuning fork tine ends. The laser, located external to the package, may be controlled automatically in response to the output of an oscillator circuit using the microresonator as a frequency standard. The package also may house electronic microcircuitry and may include a capacitor using the package wall as a dielectric. When used with the microresonator in an oscillator circuit, the capacitor enables the frequency to be adjusted slightly by shorting together capacitor plate sections on the outside of the package. A batch fabrication technique is disclosed for automatically assembling many such packages on a single scored, optionally transparent substrate.

Abstract: The disclosure relates to an acoustic surface wave device and method for long signal delays and bulk wave discrimination through the folding of a surface wave propagation path. A surface wave device is formed on the surface of an acoustic substrate and a surface wave, acoustic discontinuity is formed in the propagation path of surface waves propagated along the surface of the substrate. The acoustic discontinuity defines a reflecting surface for acoustic surface waves thereby deflecting incident surface waves along a reflecting path differing from the propagation path. Substantially all of the bulk waves propagated along the propagation path continue along this path and can be absorbed or otherwise dissipated. As a result, a substantially pure surface wave mode signal can be detected along the reflecting path. The surface waves may be reflected in this manner, i.e., by folding the path of the surface waves, a number of times as required to obtain a desired delay.

Abstract: An acoustic transducer-reflector using a single disc-shaped piezoceramic element radiating into a compound reflector for obtaining a line focus sound beam that is characteristic of focused-arc transducers that maybe used for underseas applications and for non-destructive materials testing. The single transducer emits acoustic energy into the compound reflector which reshapes a circular beam into a focused arc beam. A shadow mask or aperture stop positioned in front of the reflector assures a beam such as would be radiated from a ring source.

Abstract: A temperature compensated surface acoustic wave device having an SiO.sub.2 film layer upon a substrate of piezoelectric material. The positive temperature coefficient of delay of the piezoelectric substrate is counterbalanced by the negative temperature coefficient of the SiO.sub.2 layer. The thickness and shape of the SiO.sub.2 layer are chosen to give a zero first order temperature coefficient for the composite device. Lithium niobate and lithium tantalate are preferred piezoelectric materials for the substrate. A high degree of temperature stability is thereby obtained with coupling coefficients much greater than were previously obtained by prior temperature compensated surface acoustic wave devices.

Abstract: The invention relates to the directive transmission of elastic surface waves. The object of the invention is a device comprising a crystalline substrate on whose surface elastic surfaces waves can be propagated. The value of surface-wave phase velocity can be changed by local modification of the crystalline lattice structure in a directive zone formed immediately below the surface. The structural modification of the lattice structure can be produced by ion implantation.

Abstract: A surface wave device having a periodic frequency response characteristic is disclosed. At least two reflective grating structures are located at the surface of the surface wave device such that acoustic surface wave standing wave resonance can occur in the region between the two reflector structures. The spacing between the reflector structures is sufficiently large to insure that standing wave resonance can occur at any of a plurality of discrete resonance frequencies, all falling within the bandwidth of the grating reflectors themselves.

Abstract: A piezoelectric device comprisng a thin plate of a piezoelectric material which has a Poisson's ratio of less than one-third, and has an electrode region and a non-electrode region, wherein the thickness relation between the electode region and the non-electrode region is arranged so that the thickness of the electrode region is smaller than the thickness of the non-electrode region when a value of equations represented by (.pi.p/4)+(4/k.sup.3)cot(.pi.kp/2) Q for the thickness-extensional mode, and (.pi.q/4)+(4/k)cot(.pi. q/2k) Q for the thickness-shear mode is negative respectively for a desired vibratory mode, and that the thickness of the electrode region is larger than the thickness of the non-electrode region when the value of the above equations are positive respectively for a desired thickness vibration mode.

Abstract: A variable band pass filter circuit utilizing first and second ceramic filters including a pair of passive circuits that can be selectively connected between the ceramic filters and wherein the first passive circuit comprises a first capacitor connected between the output of the first ceramic filter and the input of the second ceramic filter and the second passive circuit includes a second capacitor connectable between the output of the first ceramic filter and the input of the second ceramic filter and an inductor connected between the input of the second ceramic filter and a reference point.

Abstract: An insulating substrate, on which is at least one single crystalline electrode and a single crystalline layer of piezoelectric material on the electrode, forms an efficient surface acoustic wave device.

Abstract: A container for a mechanical filter is provided in which the internal pressure is reduced to prevent propagation in the air of sound waves to thereby prevent deterioration of the filter characteristics. A recess with an aperture therethrough is formed in one of the walls of a metal casing which constitutes the container. Further, an adhesive tape-like member is disposed on the surface of the recess in such a manner as to cover the aperture. After the casing has been evacuated through the aperture, hermetic sealing means is provided on the adhesive tape-like member within the recess.

Abstract: A method of manufacturing an ultrasonic probe which comprises the steps of forming a first metal electrode layer fully covering one surface of a plate-shaped piezoelectric or ultrasonic vibrator and further extending over part of the opposite surface for a prescribed length; providing a second metal electrode layer electrically insulated from the first metal electrode layer and stretched over substantially the remaining portion of said opposite surface of the plate-shaped piezoelectric vibrator; brazing one of both edge portions of a first metal plate bored with many internal slits to which both ends of a plurality of leads are jointly connected, to that part of the first metal electrode layer which is disposed flush with one end face of the aforesaid plate-shaped piezoelectric vibrator, and similarly brazing one of both edge portions of a second metal plate of the same construction to that part of the second metal electrode layer which is positioned flush with the opposite end face of said piezoelectric vibr

Abstract: A transducer comprising an array of prestressed, mass-loaded, piezoelectr low-frequency, transducer elements set within a housing, a thin alignment plate bonded to the planar radiating faces of the low-frequency transducer array, a pressure-release sheet bonded to the thin alignment plate, and a high frequency, planar, transducer array bonded to this pressure-release sheet. The high frequency transducer array in combination with its two backing layers forms an integral part of the low frequency transducer array during low frequency operation in addition to providing high frequency transmission and reception during high frequency operation. This transducer construction permits high transmitting and receiving sensitivities at widely separated frequencies.

Abstract: A side looking sonar transducer which has sound absorbing material extending forwardly of the active surface of the transducer elements to diminish the acoustic response over a predetermined zone for reducing the effect of erroneous reflection signals.

Abstract: The invention concerns acoustic surface wave devices with multistrip couplers. The coupler of such a device comprises two arrays of N conductive strips connected by a connecting array and having at least one characteristic, such as for example their periodicity which is distinct for the two arrays. In modifying, for example, the ratio p.sub.1 /p.sub.2 of the periodicities of the arrays, the operation of this device is modified. This device permits in particular the construction, for wide frequency bands of utilisation of n dB couplers, energy concentrators or unidirectional transducers.

Abstract: An ultrasonic device for convergently radiating ultrasonic energy including a metallic ring vibrated to resonance by at least one electromechanical transducer fixed on the outer circumference of the ring, thereby to deliver high power ultrasonic waves from the inner circumference of the ring into the vacant center thereof.

Abstract: Acoustic waveguides, acoustic filters and acoustic reflectors are based upon the discovery of increased acoustic wave velocity in materials such as lithium niobate and lithium tantalate into which a metal such as titanium, nickel or chromium has been diffused. Velocity increases larger than 1 percent have been obtained; and negligible effect on acoustic loss is incurred thereby. The technique and the resulting devices result in a simpler structure than provided by the metallic strips or the ion beam etched surface regions of prior acoustic devices in which velocity perturbations of comparable magnitude have been desired.

Abstract: It is disclosed a quartz crystal vibrator for a timepiece having a partial electrode which is able to offset the charge produced by higher harmonic oscillation.According to this invention, higher harmonic oscillation is prevented and vibrators oscillate by only fundamental frequency.

Abstract: An apparatus for receiving electronic signals and embossing modulated grooves on a carrier medium as a function of the received signals, includes a support for supporting an embossing assembly and a carrier medium in spaced relationship therewith, as well as apparatus for causing relative motion between the carrier medium and the embossing assembly. In accordance with the invention there is provided a wafer of piezoelectric material affixed to the mount, the wafer having electrodes for application of the electronic signals. Further provided is a horn-shaped stylus member having a relatively blunt end affixed to one side of the wafer and tapering to a relatively pointy stylus end, the stylus end being positionable in contact with the medium. The horn-shaped member serves to match the mechanical impedence as between the wafer and the carrier. A dummy horn on the other side of the wafer adds a vibration reducing load to the structure.

Abstract: In a pickup for the playback of a high density signal recording stored at the surface of a record carrier, which pickup includes a scanning element and a mechanical-electrical pressure transducer connected to the scanning element by a layer of adhesive, undesired vibrations of structural parts of the pickup during playback are prevented by providing at least that part of the surface of the pickup where the pressure transducer is connected to the scanning element with a layer of a hardened casting mass, which is applied in the liquid state in which it has a viscosity of between 5 and 50 cP at 20.degree.C. Preferably, the remainder of the surface of the pickup is also covered with such a coating, with the exception of the scanning surface of the scanning element.

Abstract: A liquid level sensor for determining the liquid level in a container includes an oscillator having a feedback path including first and second piezoelectric elements mounted in a turning fork arrangement to provide a first mechanical coupling path between said elements across one end of the turning fork. This first coupling path provides a first feedback signal of one given phase. A second mechanical coupling path between said elements is provided only via the liquid when the liquid is present to a level sufficient to immerse the piezoelectric elements. The second coupling path, when present, provides a second feedback signal of opposite phase to the first feedback signal. The presence or absence of the second feedback signal determines the oscillation or non-oscillation condition of the oscillator.

Abstract: A flexural mode quartz crystal vibrator formed from a quartz crystal plate having first and second opposed substantially planar surfaces, with a plurality of electrodes on both said surfaces is provided. The vibrator is characterized by the placement of electrodes on both of the opposed surfaces so that the electrodes on each surface do not overlap each other.

Abstract: An improved monolithic crystal filter is disclosed. The filter has input and output ports formed from particular combinations of first, second and third terminals, the latter terminals having been adapted to be connected to certain preselected electrodes of the two adjacent resonators comprising the filter. More specifically, the first terminal is adapted to be connected to one of the electrodes of a first one of the aforesaid two resonators, the second terminal to the other electrode of the first resonator and to one of the electrodes of the second of the two resonators, and the third terminal to the remaining electrode of the second resonator.

Abstract: The invention describes a low cost transducer construction utilizing a vibratile diaphragm to form a closure for a cylindrical tubular housing. The sound radiating surface of the diaphragm is of a concave shape to achieve an increased diaphragm thickness at its periphery. The concave diaphragm design permits the precise adjustment of the resonant frequency of large quantities of mass produced transducers by machining the surface of the thick rim portion of the diaphragm. Greater precision in the adjustment of the resonant frequency is achieved with this design because the frequency change is less critically dependent on the amount of material removed than is the case with a conventional flat diaphragm surface as used in prior art designs.

Abstract: A thin quartz oscillator element including a substrate of quartz with a plurality of electrodes disposed on a major surface of the substrate and extending outwardly beyond one edge of the substrate. Metallic bodies are disposed on the same surface of the substrate as the electrodes remote from the electrodes. The electrodes thicken in the region that extends beyond the edge of the substrate to a sufficient thickness to be thereby reinforced. Another electrode made as a metallic layer is built-up on the opposite major surface of the quartz substrate. To construct the quartz oscillator, an upper and a lower major surface of a quartz substrate are lapped. The substrate is mounted on a jig, and a metallic layer is deposited on a surface of the substrate and extending from one end thereof. The metallic layer is coated with photo-resist, the photo-resist is exposed to light through a mask, and the photoresist is then developed to remove unexposed photo-resist.

Abstract: An electroacoustic transducer uses a bilaminar vibratile element having at least two plate members which are bonded together in face-to-face relationship, at least one of the plates being made from a piezoelectric material. The bilaminar plate is supported within a frame-like structure by resilient pads which attach the bilaminar plate at its nodal points to the surface of the supporting frame.

Abstract: The invention relates to vibratory devices, and more particularly to tools designed to be vibrated at an ultrasonic rate for vibratory energy transmission.

Abstract: An easily replaceable acoustic transducer assembly is provided for usage in high temperature applications. The improved structure permits efficient acoustical coupling between the component parts of the tranducer assembly, and is more readily reproducible in sensitivity and frequency response. A generally tubular high temperature resistant metal enclosure is provided with an acoustical window which is coupled to the piezoelectric transducer element. The piezoelectric element is acoustically coupled to a damping block member. Acoustical coupling between the active elements of the transducer assembly is had from a compressive means integral within the enclosure member.

Abstract: An ultrasonic cutting apparatus comprising a tuning fork or U-shaped flexural member having legs on which cutting means are mounted, and an ultrasonic drive connected to the flexural member for inducing ultrasonic vibrations in the flexural member. Also disclosed herein is an ultrasonic drive member having a "folded over" resonant holder, and a piezoelectric crystal compressively mounted in the holder by coupling means for transmitting the ultrasonic excitation from the drive to the flexural member.

Abstract: Surface acoustic waves on a piezoelectric crystal substrate beat with the bulk shear wave energy generated by the incident surface wave and which pass through the thickness of the substrate to produce a beat signal which is collected and is useful in pulse systems.

Abstract: A ceramic package is disclosed which comprises a frame member having an ature for accommodating a crystal resonator. The frame member includes mounting clips for supporting the crystal resonator in a desired vibratory mode. A bottom and top lid are then fastened to the frame to enclose the crystal to also enable hermetic sealing in an ultra high vacuum without the use of large deleterious forces.The package provides a hermetic enclosure enabling improved frequency stability and overall reliability.

Abstract: In a mechanical filter, a pair of transducer elements of truncated circular cross-section are disposed at the input and output sides respectively, and they are mechanically connected in cascade to each other by means of a coupler member. The areas of the truncated cross-section of the transducer elements are made different from each other. Between said pair of transducer elements may be provided one or more resonator elements each provided with a recess and connected to each other and to said transducer elements by said coupler member. Each of the transducers and resonators are mounted on a mount base plate by means of a bent wire-like support member having a pair of legs. The foregoing mechanical filter is accommodated in a container which is pressure-reduced and hermetically sealed.