Abstract: The invention relates to a piezo-electric crystal reasonator comprising a tuning fork having two tines, one on each side of an axis of symmetry, having in addition to the excitation electrodes formed on the tines, auxiliary electrodes comprising conductive coatings formed, with the same axis of symmetry, on the same crystal which interconnects the two tines and further relates to a method for making such tuning fork resonator including the detection of asymmetry by applying an excitation voltage to the excitation electrodes to cause the resonator to oscillate, and while it is oscillating, detecting a voltage appearing between the auxiliary electrodes to indicate asymmetrical oscillation of the tines.In addition to excitation electrodes (5, 6, 7) on the tines (2, 3) of the tuning fork, auxiliary conductive electrodes (17, 18, 19, 21) are formed on a part of the resonator which interconnects the two tines.

Abstract: A mode coupled tuning fork type quartz crystal vibrator utilizing two different vibrational modes is provided. The vibrator includes at least one electrode on each tuning fork arm for adjusting the resonant frequency of the main vibration and an electrode for adjusting the frequency-temperature characteristic of the vibrator. The main vibration is in the flexural mode (F.sub.1) and the sub-vibration is in the torsional mode (T.sub.0). The resonant frequency of the first overtone in the flextural mode is designated by f.sub.F and the resonant frequency of the fundamental vibration in the torsional mode is denoted by f.sub.T. The difference between f.sub.F and f.sub.T defined as .DELTA.f=f.sub.F -f.sub.T determines the frequency-temperature characteristics of the mode coupled vibrator.The electrodes for adjusting f.sub.F are substantially triangular in shape and the electrodes for adjusting f.sub.T are substantially rectangular in shape.

Abstract: Doubly rotated quartz crystal blanks such as the SC, IT and FC cuts have ir apparent angles of cut and hence their frequency vs. temperature characteristics modified by changing the contours of one or both of the convex sides thereof, or by changing the electrode areas thereof; or a combination of these two changes.

Abstract: A quartz vibrator mounted on a terminal substrate member having a through-hole. The ratio of through hole area being from 0.5 to 0.8 of the vibrators electrode area. Fine frequency adjustment is obtained by evaporation of material thru the through hole.

Abstract: A driving electrode on a surface of the piezoelectric vibrator in accordance with the present invention has a blank which is narrow at the center portion and wide at the right and left portions on the Z axis. And the driving electrode is the shape easy to operate in the fundamental main vibration, and hard to operate in the spurious vibration. Thus the piezoelectric vibrator operates efficiently in the fundamental main vibration.

Abstract: A tuned acoustic directional transducer for transmitting and receiving airborne sound, which provides enhanced efficiency and reduced cost without undue narrowing of bandwidth, makes use of an acoustic transducer element (2) coupled to a plate (10) having a higher order flexural mode resonance at approximately the desired frequency of operation, the plate being coupled to the air through low-hysteresis acoustic propagation material having an acoustic impedance much less than that of the plate and much greater than that of the air. The material is disposed so that in the desired direction of propagation there is no substantial reduction of sound intensity in the far field resulting from cancellation occasioned by interaction of sound radiated from adjacent antinodal zones. Preferably the thickness of the material is such that it acts as an efficient acoustic impedance matching transformer.

Abstract: A wafer of piezoelectric material is provided with electrodes on opposite surfaces thereof. Frequency fine tuning of such resonators is accomplished by relatively thin film of metal applied over the surface of at least one electrode and the adjacent non-electroded wafer material. The metal film is of such small maximum thickness that it functions as a quasi-insulator and is extremely stable over prolonged operating conditions so that the resonator parameters remain constant.

Abstract: Cutting a quartz tuning fork crystal vibrator at a preferred angle and with a thickness which establishes a close coupled relationship between the flexural and torsional modes of vibration of the arms or tines produces a vibrator having a highly favorable cubic frequency temperature characteristic at predetermined frequencies. Weight added to the ends of the vibrating tines reduces the frequency of both flexural and torsional vibration, whereas weight added at nodal points in the flexural vibration primarily reduces only the torsional vibrational mode. Accordingly, a wide range of frequency adjustments is possible. Deviations from the desired crystal operating frequency due to manufacturing variances are adjustable by sequential weight modifications while the desirable cubic temperature characteristic is retained. High accuracy over a wide temperature range permits operation in oscillator circuits at relatively low frequencies and with attendant low power consumption.

Abstract: A method and kit for determining the total amount of an immunologically-reactive substance in a liquid sample containing interfering material capable of binding to an antigen. The method involves the steps of: (1) contacting a liquid sample containing or suspected of containing an antibody with the surface of a piezoelectric oscillator having a layer of antigen specific for the antibody attached thereto; (2) washing and drying the oscillator; (3) measuring the resonance frequency of the oscillator; (4) contacting said surface of the oscillator with a liquid reagent containing an excess amount of a substance specifically reactive with all of the antibody bound to the oscillator in step (1); (5) washing and drying the oscillator; and (6) measuring the change in resonance frequency of the oscillator form the first measurement whereby the amount of total antibody bound to the oscillator in step (1) is distinguished from the interfering material bound in step (1).

Abstract: A thickness-shear mode piezo-electric vibrator comprises a piezo-electric crystal operable in the thickness-shear mode, driving electrodes formed on opposed surfaces of the crystal, and an addition mass formed on at least one of the driving electrodes and positioned on the nodal line of a 3-fold harmonic vibration so that the frequency f.sub.o of the fundamental main vibration and the frequency f.sub.3s of the 3-fold harmonic vibration always satisfy the following relation within the practical application ranges of temperature and load capacitance; ##EQU1## thereby effectively eliminating or preventing the "abnormal frequency phenomenon" which would otherwise occur due to the 3-fold harmonic vibrations.

Abstract: An improved indirect assay and article for determining an antigen in a liquid sample. The assay utilizes a piezoelectric oscillator which has been coated with the antigen or a protein mixture containing the antigen being determined. The antigen-coated oscillator is contacted with the liquid sample and a predetermined amount of an antibody specific for the antigen being determined. The amount of free antigen in the sample, if any, can be determined by measuring the change in frequency of the oscillator following contact with the liquid sample and the antibody, and referring to a standard curve.

Abstract: A method and article for the determination of a particular subclass of antibody, e.g., IgA, IgE, IgM, etc., are disclosed. The method utilizes a piezoelectric oscillator having bound to the surface thereof an antigen specific for the antibody being determined. The antigen-coated oscillator is exposed to a solution containing an unknown amount of the antibody. After the antibody in the solution has attached to the antigen on the oscillator, the oscillator is exposed to a substance (sandwiching substance) which selectively binds to a specific subclass of the antibody being determined. The frequency of the oscillator is measured before and after exposure to the sandwiching substance. The change in frequency is related to the amount of the subclass of antibody bound to the oscillator, and the amount of the subclass of antibody in the solution can be quantified by reference to a standard curve.

Abstract: A monolithic crystal filter formed by a multi-section piezoelectric resonator having anodizable electrodes is subjected to plasma from a low energy oxygen glow device to adjust the frequency response. The electrodes are selectively connected to potentials whereby the electrodes are individually anodized to increase the density thereof and change the frequency response of the resonator. The glow device includes anode and cathode rings separated by an insulator ring which holds a cathode screen across the cathode. The anode ring has a concave face and the inside diameter is generally the same as the diameter of the resonator so that the resonator can be placed close to the anode and plasma is localized on the resonator electrodes. The electrodes are connected in a frequency measuring circuit so that the response is monitored and the extent of anodization of the individual electrodes is controlled.

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: The vibrating element comprises a pair of exciting electrodes having opposing effective portions formed on the opposing major surfaces of a piezoelectric plate, and vibration adjusting members disposed on at least one of the exciting electrodes. The vibration adjusting members are made of the same material as the exciting electrodes and do not project beyond the contour of the effective portions in the direction of propagation of the vibration energy of the vibration but project in a direction perpendicular to the direction of propagation.

Abstract: A thickness-shear mode quartz oscillator characterized in that an addition mass fitted to a driving electrode of the oscillator for the purpose of adjusting its oscillation frequency has a non-circular shape or the fitting position thereof is deviated from the center of a quartz slice, or both in combination. Such addition mass provides different piezoelectric effects and effects of addition of the mass between the fundamental main vibration and harmonic vibrations and eliminates or restricts a "frequency abnormal phenomenon". Consequently, even when driven by a C-MOS type integrated circuit not having a frequency selection circuit in its oscillation loop, the thickness-shear mode quartz oscillator exhibits stable frequency-temperature characteristics.

Abstract: The resonant frequency of piezoelectric transducers is made more uniform from unit to unit by reducing the sensitivity of that frequency to manufacturing variations in the diameter of the ceramic sensing disk that forms a part of the vibratory diaphragm assembly. The diaphragm member proper is stiffened, as by integrally formed radial ribs, within the zone of variability of the disk perimeter, effectively establishing a uniform boundary edge for the diaphragm area that is stiffened by presence of the disk.

Abstract: A conventional tuning fork type quartz crystal resonator has mainly two vibration modes. They are fundamental vibration mode and overtone having the resonance frequency six times as much as the frequency of fundamental vibration. These two vibration modes have similar high quality factors. When this resonator is put to practical use, there are instances where it oscillates in undesirable mode of vibration. Accordingly, in this invention, concave portions are provided at the tops of resonator in order to prevent it. It is the most effective in case that concave portions are provided in the region of 0.65 to 0.85 from roots of arms.

Abstract: An ultrasonic transducer and a method for manufacture thereof in which a piezoelectric crystal is bonded to a flat diaphragm with the neutral bending axis of the crystal/diaphragm combination being within the bonding agent. The diaphragm is then pressed into the open end of a hollow shell. The resonant frequency of the shell, diaphragm and crystal combination is determined by the extent to which the diaphragm is pressed into the shell and, in the preferred example disclosed, is set at about 19.8 KHz. The shell cavity is then filled with a mixture of RTV and a nonconductive particulate material at a weight ratio between 5/1 and 20/1. This mixture lowers the Q of the transducer while also raising its resonant frequency to the desired 20 KHz.

Abstract: A composite low frequency transducer that makes it possible to lower the ural frequency and use higher power levels than can be obtained with a ceramic transducer alone. The transducer includes metal and ceramic elements. The metal element consists of a cylindrical shell which is multiply slitted longitudinally and alternately from each end, the alternate slits extending substantially but not completely to the opposite end. The ceramic transducer element is cylindrical and is in contact with and centrally positioned within the slitted exterior shell. The resulting composite transducer operates at a frequency which is several octaves less than the natural lowest frequency of the ceramic transducer alone.

Abstract: The resonant frequency of a conventional piezoelectric transducer having predetermined dimensions and a fundamental nodal diameter is reduced while maintaining the overall predetermined diameter and fundamental nodal diameter of the transducer. A method of reducing the resonant frequency of a conventional piezoelectric transducer includes the step of radially slotting the substrate of the transducer.

Abstract: A method is provided for adjusting the resonant frequency of an aluminum plated quartz resonator so as to reduce the effect of aging. The method comprises initially forming the aluminum plated resonator so that its frequency is above the nominal frequency, and then reducing the frequency to the nominal value by anodically forming an oxide film with a thickness in excess of 50A on the aluminum plating.

Abstract: The apparent angle of cut of a quartz crystal resonator blank is shifted so as to give the quartz resonator a desired frequency versus temperature characteristic.

Abstract: A method of adjusting the frequency and temperature coefficient of a GT cut quartz oscillator comprises starting with a blank of approximately the frequency desired. An electrode film is deposited on the front and rear faces of the blank. The side ratio between a longer side and a shorter side is adjusted to obtain a zero temperature coefficient. Thereafter portions of the electrode film along the longer sides of the oscillator are removed to reduce the area of the electrode film so as to obtain the desired frequency without changing the side ratio and thus without disturbing the zero temperature coefficient.

Abstract: The present invention relates to the manufacture of surface acoustic wave transmission devices. The invention provides a method of cutting the edges of surface acoustic wave devices, which consists in directing on to that face designed to propagate said waves, a jet of abrasive particles.

Abstract: A method for stabilizing the vibration frequency of an oscillator which contains a tuning fork-type quartz crystal element comprising a pair of arms each having a given size and a common connecting section connecting the mutually facing ends of the paired arms.