Abstract: The resonator according to the invention comprises at least one quartz crystal in the form of a rectangular thin plate, of which the length l is directed along an axis X', the width w along an axis Y' and the thickness t along an axis Z', and which vibrates in a contour mode. The axis Z' is situated in the plane of the electrical axis X and optical axis Z of the crystal and forms with the axis Z an angle .phi. such that16.degree.<.phi.<36.degree.and the axis Y' forms with the mechanical axis Y of the crystal an angle .theta. such that10.degree.<.theta.<30.degree.This resonator presents a zero temperature coefficient of the first order and is not dependent to any critical extent on the dimensional ratio between the sides w and l of the plate; the temperature coefficients of higher order are very small. The piezo-electric coupling is such that the optimized mode of oscillation is the only one excited in practice.

Abstract: In an exemplary embodiment a transducer comb for an ultrasonic array or a compound scanner consists of a specifiable number of transducer elements joined together in a specific area formation, the width of each transducer element being smaller than its height. In the case of sonic heads of this type, given an optimum radiation or receiving power, respectively, the lateral resolution is to be significantly improved. This is achieved by a transducer element arrangement comprising a fine subsidivision of the transducer elements in such a manner that the width of each individual transducer element lies markedly below half the wavelength (.lambda./2) of the radiated, or received, ultrasonic waves, whereby, however, within the arrangement, in each instance, always a specified number of transducer elements of the fine subdivision is combined into a group through parallel-connection.

Abstract: A yzw 35.degree.0' thickness shear crystal bar is provided with bevels cut n its longest narrow surfaces (b, c) proximate the ends in order to obtain energy trapping of the coupled mode vibrations which may arrive at said ends and thus permit shortening of the bar for a given quality factor.

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 method which permits highly stable frequency adjustment of piezoelectric crystal devices to tight tolerances. Small fragments of the crystal (10) which resemble conchoidal shells (18) are removed from at least one surface (11) of the crystal plate by fracturing. In one example, this is accomplished by applying pressure from a sharp-pointed stylus (20) near the edge of the plate.

Abstract: An AT-cut piezoelectric crystal resonator having a plurality of contoured surfaces, two of these contoured surfaces being generated by translating contour lines parallel to the z-axis and perpendicular to the electric axis. At least one of these two surfaces is convex, and another two contoured surfaces are perpendicular to the z-axis and spaced apart by a length dimension z'.sub.0 which is 0.1 to 1.3 of the maximum thickness dimension representing the distance between the first mentioned two surfaces and measured along a line perpendicular to the x-axis. The resonator is adapted for performing a mode of vibration along the thickness forming either a fundamental standing wave or an overtone thereof of a thickness-shear vibration. The free ends of the vibration are positioned at the first mentioned two surfaces, and the amplitude of vibratory displacements appearing along the x-axis is maximum at the center of each surface of the first mentioned two surfaces.

Abstract: Piezoelectric microresonators with suspension arms, oscillating according to a vibration resulting from the superposition of a principal extensional mode of oscillation, of a first shear coupled mode of oscillation and of a second extensional coupled mode of oscillation. The suspension arms are attached to the active part of the resonator in a place which is the intersection of a nodal plane of the vibration resulting of the superposition of the principal mode and of the first coupled mode of oscillation. The other end of the arms is fixed on a stiff support in a location which coincide with a node of their vibration.

Abstract: Filter chain comprising at least two cascaded duals, each provided with two acoustically coupled resonators, only one of the two resonant frequencies of each of the duals falling within the filter pass band; the duals are convex at least on one side so as to render the acoustic coupling between the resonators so strong that the distance between the two resonant frequencies of the dual is as great as possible.

Abstract: This disclosure relates to improved piezoelectric quartz crystal products preferably used in quartz crystal filter and resonator applications, and fabrication methods therefor. Various embodiments are disclosed including a substantially circular, a square, and a rectangular quartz crystal product wherein each one contains a single triangular shaped electrode located on each of the two sides thereof in an overlapping arrangement. Other embodiments disclosed include a substantially circular, a square, and a rectangular quartz crystal product wherein each one contains multiple electrodes such as two spaced apart triangular shaped electrodes located on each side of the two sides thereof in an overlapping arrangement.

Abstract: A piezoelectric relay construction in which the active element comprises a bimorph sheet having a substantially "U" shaped perforation therethrough to present an armature section having a free end deflectable within the boundaries of the sheet and a frame section for the armature section. A first contact is mounted on the free end of the armature section and a second contact is mounted in opposition to and spaced apart from the first contact on a conductive clip affixed to the frame section. Remanent polarizations are induced in the piezoelectric layers of the bimorph sheet which are in opposition in the armature section and the frame section of the sheet. Suitable terminals on the frame section interconnected with circuit means including the electrode surfaces of the bimorph sheet are provided for the application of operating voltages.

Abstract: A piezoelectric resonator, particularly for electronic wrist watches, comprises an elongated piezoelectric crystal rod that oscillates in length-extension. Opposite faces of the rod are partially metallized; and short wires are secured tangentially to these metallized surfaces midway of the length of the rod. The wires extend perpendicular to the length of the rod and are secured at their other ends to metallized opposite surfaces of an elongated ceramic support which is parallel to and of about the same size and shape as the rod. The support also has metallized end faces which are secured to the inner ends of support wires that pass through a casing in sealed relationship and mount the support and rod in spaced relation from the casing.

Abstract: At least one of several transducers on a piezoelectric substrate is externally short-circuited by a series resonance circuit for suppression of triple transit echoes. The resonance circuit is additionally connected to an amplifier via a high input or output impedance. In multi-transducer systems any two transducers are prevented from communicating via echo signals by such resonance circuits. In filter cascades several resonance circuits may be included in the interstage coupling circuit or between the input and output amplifiers on the one hand and the cascade on the other hand.

Abstract: An improved acoustic waveguide structure which comprises a ridge waveguide disposed in a horizontal direction extending outwardly from a substrate. The horizontal orientation of the waveguide which is in the form of a ledge results in particle motion of the ledge predominantly normal to the substrate plane with the largest motion at the free edge of the ledge and almost no motion in the substrate, thereby permitting a plurality of such structures to be densely packed on a common substrate.

Abstract: A transducer of the type converting between electrical and mechanical energy by means of the piezoelectric effect in a supported sheet of uniaxially oriented, electrically polarized thin high polymer film such as polyvinylidene fluoride, having surface electrodes thereon for connection to an electrical circuit. The transducer is characterized by an arrangement of the piezoelectric film into a series of elongate curved cylindrical segments of alternating sign of curvature, with the surface electrodes on the film being divided in selected locations between adjacent segments. A useful level of elastic stability is achieved without using a static pressure difference on the film, good electromechanical coupling is attained, and the individual transducer elements formed by the divided surface electrodes may be usefully interrelated electrically to substantially cancel even order harmonic distortion and enhance linearity of operation.

Abstract: An improved acoustic waveguide structure which comprises a ridge waveguide disposed in a horizontal direction extending outwardly from a substrate. The horizontal orientation of the waveguide which is in the form of a ledge results in particle motion of the ledge predominantly normal to the substrate plane with the largest motion at the free edge of the ledge and almost no motion in the substrate, thereby permitting a plurality of such structures to be densely packed on a common substrate.

Abstract: A surface acoustic wave filter has a Lithiumniobate substrate of parallelogram configuration, which is bonded to a header having similar acoustic impedance. The substrate has three transducers arranged along its long sides at particular spacings destined to suppress triple transit echoes. The short sides are oblique and surface portions adjacent thereto are covered by surface waves attenuating paddings. Two such filters are cascaded on the same header.