Abstract: A small low frequency acoustic receiver which is formed into a cylinder or ing by use of a plurality of separate elements of piezoelectric material. Each element is secured with its sides in face-to-face relationship with an electrode between each joined face in contact with each adjacent element. The electrodes are alternately connected into an electrical circuitry for transmitting electrical signals to a receiver.Other construction techniques may be used to assemble separate elements in a cylindrical arrangement. Over a band of very low frequencies, the cylinder or ring has a high sensitivity (i.e., it produces a large electrical signal) to sound incident in the axial direction compared with its sensitivity in the radial direction. Over this band of very low frequencies the sensitivity of the cylinder or ring is relatively constant for sound incident in the axial direction.

Abstract: An elastic surface wave device comprises a piezoelectric body and interdigital type electric signal-surface wave conversion conductors formed one at each end portion of one surface of the piezoelectric body. A groove elongated in a surface wave propagation direction is provided in a surface opposite to the surface on which the conversion conductors are formed.

Abstract: In a crystal element of the type wherein a DT-cut crystal element is used to generate vibrations of the contour mode, one side of the crystal element is flat and the thickness of the element is gradually decreased from the center toward the periphery thereof.

Abstract: An electro-acoustic transducer with a piezoelectric diaphragm which is backed with a plurality of different resilient members for imparting a suitable resiliency and/or tension to said diaphragm to highly improve its acoustic characteristics with a simple construction.

Abstract: A piezoelectric electro-acoustic transducer employing as a diaphragm a uniaxially stretched film of a shape having the major axis and the minor axis, wherein the expansion-contraction direction of the diaphragm, in which a piezoelectric constant is at a maximum, is substantially in parallel with the minor axis thereof, whereby the piezoelectric electro-acoustic transducer can provide a high converting efficiency, especially in the low frequency range.

Abstract: An electromechanical transducer employing an arcuate piezoelectric shell element having lateral edges affixed to a restraining member wherein stresses produced in the element by electrical energy produce element flexural vibrations. The piezoelectric shell element and restraining member are located within a chamber defined by a boot and rigid end caps attached to the restraining member. Hydraulic fluid within the transducer chamber equalizes pressures upon the shell element functioning as an acoustic coupling and as a pressure equalizer. In an embodiment of the invention a pair of piezoelectric shell elements are attached to opposite sides of a planar restraining plate.

Abstract: An ultrasonic transducer comprising a linear array of piezoelectric elements for converting a single line from a compressional acoustic image field to electrical impulses which, in turn, provide a means for converting the incident compressional image field to a visual representation. In order to match the configuration of the acoustic image field, the array of piezoelectric elements, in a preferred embodiment, has the configuration of an arc, that is, the array is arranged in a straight line in one plane and in an arc in a plane orthogonal to the first. The transducer is made up of a plurality of assemblies each of which is composed of segments of piezoelectric material each held in a supporting slot in a length of metal plate which slot is filled with a material selected to provide impedance matching between the piezoelectric material and the transmission medium.

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 large depth-of-field arc-transducer for use in sonar systems is provided in which at least one transducer element is positioned to lie along the arc of a circle of radius R. The active faces of the transducer elements are directed to a point that lies on a line normal to the plane of the arc and passes through the center thereof. The radius R is equal to between 0.3 to 0.6 Rs and, preferably about 0.5 Rs, where Rs is the distance from said point to the midpoint of the arc-transducer.An improved depth-of-field sonar system is provided where at least two arc-transducers are used having different radii, and preferably, where each radius R is equal to between 0.3 to 0.6 Rs.

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: An acoustic surface wave filter comprising a monocrystalline wafer of bismuth silicon oxide having a special orientation of the ASW propagation surface and the interdigital transducers relative to the crystal plane whereby pick-up of undesired bulk waves is reduced.

Abstract: A piezoelectric-type electroacoustic transducer composed of two convex or concave piezoelectric polymer films each having electrodes on both surfaces thereof, said two polymer films being so connected to electric wiring that, when the one of the piezoelectric polymer films elongates by the action of an electric field in one direction, the other shrinks by the action of the same electric field.

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: 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.