Abstract: A vibrator 10 includes a regular triangular prism-shaped vibrating body 12. On centers of three side faces of the vibrating body 12, piezoelectric elements 14a, 14b and 14c are formed, respectively. Two piezoelectric elements and 14b are used for driving and detecting. The other piezoelectric element 14c is used for feedback. By trimming a ledge-line portion 12a of the vibrating body 12, a resonance frequency on driving side is controlled. By trimming ledge-line portions 12b and 12c of the vibrating body 12, two resonance frequencies on detecting side are controlled.

Abstract: A piezoelectric tuning fork resonator having a piezoelectric substrate provided with a stepped portion on its end and a tuning fork arm portion formed in the stepped portion. A dummy substrate is arranged adjacent to a side of the piezoelectric substrate and a pair of sealing substrates are pasted onto upper and lower portions of the piezoelectric substrate and the dummy substrate to form a chip type piezoelectric tuning fork resonator. In another embodiment, the piezoelectric substrate includes a resin sealing portion having a hollow portion defined around the tuning fork arm portion so as to form a resin-coated piezoelectric tuning fork resonator.

Abstract: A quartz crystal resonator is utilized to effect evaluation of the viscoelastic characteristic of a film deposited on an electrode by an electrochemical reaction. The quartz crystal resonator is connected to a resonator characteristic measurement unit comprised of an oscillating circuit, a frequency counter, and an amplitude level meter. An electrochemical measurement unit in the form of a potentiostat is connected to a working electrode which comprises one of the electrodes of the resonator, to a reference electrode and to a counter electrode. The frequency counter, the amplitude level meter and the potentiostat are connected to a CPU. The resonator, reference electrode and counter electrode are all immersed in an electrolyte solution in an electrochemical cell.

Abstract: A vibrating beam accelerometer contains an inner structure having a vibrating beam extending between a pair of isolator masses which are connected via isolator beams to a pair of structures, an outer structure having flexure beams extending between a mount structure and a proof mass structure and a peripheral seal structure surrounding said inner structure and said outer structure. Seal plates containing a ring of glass frit material sandwich the above assembly. An electrode pattern termination extends from the above assembly, through the ring of glass frit material, to electronic circuitry containing an oscillator.

Abstract: A personal alert safety system, having visual and audio safety components, in a small, lightweight, high impact casing with two compartments separated by a planar wall providing a watertight wall between the two compartments, the planar wall being a sealed laminated piezoelectric sound transducer. One of the compartments is sealed to provide a watertight chamber containing the electronic and electrical control and operating circuitry for the system. The second compartment is a resonating chamber with sound ports for the piezoelectric sound generating transducer. Two manual switch operators are located on opposite exterior sides of the casing and in a sealed manner actuate switches in the interior circuitry to turn the unit on and off, and simultaneous operation of both switches is required to turn the system "on" or "off". A vibrating accelerometer motion detector is included within and connected with the circuitry inside of the casing.

Abstract: Since split electrodes are disposed along the x-axis of an AT cut quartz crystal plate on its ultrathin vibratory portion formed integrally with a thick frame-like marginal portion surrounding it, desired acoustic coupling can be obtained although the split electrodes are disposed closely to such an extent as not to cause shorting between them. It is therefore possible to obtain, with a satisfactory yield, filter elements which have center frequencies in the range greater than about ten megahertz and sufficiently wide passbands.

Abstract: In a linear-type actuator where an elastic wave is excited upon the vibrator composed of a rod shaped elastic member and a piezo member so as to drive the moving member bought into pressure contact upon the vibrator, the present invention provides a linear-type actuator where the improvement of the driving efficiency and the simplification of the driving circuit can be achieved by the new driving principle.

Abstract: A vibrating surface gyroscope includes a piezoelectric resonator 10 of material arranged to have a plurality of poles 12, 14 of opposite sense or polarity disposed around the sensing axis. The resultant bi-directional (forward and reverse) poling establishes the mode and modal position of a vibration in the resonator 10. One surface of the structure includes a surface electrode having a surface resistivity comparable with the reactance of the piezoelectric material adjacent resonance so that a bridge circuit can be made up of the electrode and the piezoelectric material. A wideband closed loop system provides feedback into the bridge to maintain it at balance and provides rate output. Scale factor compensation techniques are also disclosed as well as alternative electrode arrangements.

Abstract: Mechanical resonator and method in which electrodes or other driving and sensing elements are energized with an AC voltage to produce oscillations in a tine. The electrodes or other driving and sensing elements have at least two parameters which are adjusted to selectively enhance oscillations in one mode, e.g. the fundamental mode, and/or to selectively suppress oscillations in one or more other modes, e.g. an overtone mode. The parameters which can be adjusted include the endpoints of electrodes, the width of a gap between adjacent ends of electrodes, and corresponding features of other driving and sensing elements.

Abstract: A vibration control apparatus comprises a vibration member having a surface with a resonance point. A piezoelectric element is adhered to the surface of the vibration member. A drive apparatus is connected to the piezoelectric element via an impedance element for exciting the piezoelectric element with an A.C. signal. A feedback circuit is connected between the piezoelectric element and the drive apparatus. The feedback circuit picks out the components of a voltage on the piezoelectric element caused by a strain of the piezoelectric element and feeds this voltage back to control the drive apparatus. The inventive vibration control apparatus may be incorporated in a gyro to simplify the construction of the gyro.

Abstract: A vibrator is disclosed having a vibrating body with a polygonal lateral cross-section. Two piezoelectric elements are disposed on nonparallel side surfaces of the vibrating body. A support structure is provided which supports the vibrating body at two support points of the vibrating body. The support points are located in a split plane which passes through the line of intersection of the two planes in which the two side surfaces lie and bisects the inner angle formed by these two planes. Furthermore, the support points are located on opposite sides of the vibrating body and each support point is located at or near a nodal point of the vibrator.

Abstract: An electronic device (100) includes a housing (222) and a piezo-bender (400). The piezo-bender (400) includes a metal beam (402) having at least a portion of a surface mechanically coupled to a piezo-ceramic layer (304). The piezo-bender (400) is flexibly coupled to the housing (222) at an end of the metal beam (402) forming a cantilever structure. A vibratable body (404) is mechanically coupled to the other end of the metal beam (402). A tuning slide (604) is slidably coupled to the piezo-bender (400) for mechanically tuning the resonant frequency of vibration of the piezo-bender (400) by varying the length of the piezo-bender (400) that can vibrate. An electrical drive circuit (708) is electrically coupled to the piezo-bender (400) for electrically driving the piezo-bender (400) with a drive signal to generate vibratory motion in the piezo-bender (400) for providing a vibratory alert.

Abstract: In a resonator which has an ultrathin vibratory portion formed integrally with a thick frame-like rib surrounding it, a pair of opposed thick marginal portions of the frame-like rib are formed so that their widths gradually decreases toward another marginal portion of the rib from the other remaining one perpendicular to the above-noted pair of opposed marginal portions and to be fixed to a resonator case. This structure substantially increases the mechanical strength of the piezoelectric resonator, even if it is held in a cantilever fashion, and protects it from breakage by an external vibration or shock.

Abstract: The present invention proposes an ultrasonic wave linear motor constituted in such a way that an oscillatory element for making oscillation in a direction crossing the shaft line of an oscillatory member is attached to the oscillatory member made of an elastic body formed in a rod shape and a driven body capable of making free relative movement in a direction crossing the shaft line in relation to the above oscillatory member is arranged to abut the end of the above oscillatory member, and also proposes such a driving process that, the ultrasonic wave linear motor makes linear movement by exciting flexural oscillation and longitudinal oscillation on the above oscillatory member by means of the oscillation of an oscillatory element so that an elliptical oscillation composed of flexural oscillation and longitudinal oscillation may take place on the surface of the oscillatory member in contact with the driven body.

Abstract: An apparatus for converting a mechanical force into an electrical signal. The apparatus includes a piezoelectric disk crystal (1), connecting electrode layers (2, 3) disposed on opposite sides of the disk-shaped crystal (1), the electrode layer (3) on the one side being divided into a transmitter electrode layer (6) and a ground or o-electrode layer (5), and the electrode layer (2) on the opposite side being divided into a receiver electrode layer (7) and a ground or o-electrode layer (8).

Abstract: To produce a piezoelectric tone generator, a layer of filler-free bonding agent whose dynamic viscosity is 800 to 18,000 mPa.multidot.s is applied between a metallized carrier plate and a piezoceramic wafer. The package composed of carrier plate, bonding layer and ceramic plate is pressed together, the quantity of bonding agent being chosen to be so large that during pressing a bead covering the edge of the ceramic wafer is formed. The bonding layer is cured thereafter, firstly catalytically or thermally and then by UV irradiation.

Abstract: A transducer for a stringed musical instrument incorporating an electrically conductive ground plane, along with a piezoelectric transducer and a conductive strip. The piezoelectric transducer is comprised of a polyvinylidene flouride co-polymer. The ground plane, piezoelectric transducers and conductive strip are secured in a elongated unitary structure with the ground plane and conductive strip disposed on opposite sides of the transducers. A conductive shield is disposed about the unitary structure and electrical leads connect to the ground plane and conductive strip, respectively.

Abstract: A device to eliminate ice formed on the surface of a wall, notably on the surface of an optical or radio-electric window, comprises a piezoelectric material having a vibrating active surface that mechanically cooperates with the wall to be de-iced, and means for the polarization of this piezoelectric material, comprising an AC voltage source and conducting or semiconducting electrodes placed in contact with this material according to a geometry capable of generating, within this material, an acoustic wave that has a direction of vibration which is oriented longitudinally and/or transversally to said surface to be de-iced, the amplitude of this vibration being sufficient to respectively detach and/or break the deposit of ice formed on said surface. The piezoelectric material is preferably a ferroelectric polymer such as a polymer of the group comprising PVF.sub.2, PVF.sub.2 -TrFE, PVDCN-VAc, PVF.sub.2 -TFE and the mixture of these polymers with one another and/or with PMMA or PEMA.

Abstract: A vibration gyro having a substantially H-shaped vibrator, driving piezo-electric elements, detecting piezo-electric elements which detects Corioli's force generated when an angular velocity is applied to said vibration gyro during the vibration by the driving elements, and a supporting member supporting the vibrator, characterized in that the detecting elements are formed of a torsional piezo-electric material.

Abstract: A method and apparatus directed to a thin film piezoelectric resonator deposited on a support layer of dielectric material and being configured in the form of a cantilever structure having a base portion formed on an integrated circuit substrate and having an overhanging beam portion joined at one end to the base portion, with the opposite end being unsupported with an air-gap intermediate the beam portion and the substrate. In the fabrication of the resonator, a thin film of dielectric material, e.g. zinc oxide (ZnO) is first deposited on the substrate, but is subsequently removed from beneath the beam portion resulting in the air-gap which is open on three sides and thus results in a greater ease of fabrication.

Abstract: A path length control driver apparatus includes a base plate having a first central member having first and second opposite ends, a first outer rim membr and a first flexible annular diaphragm area having first and second opposite sides. The first flexible annular diaphragm area is between and integral with the first central member and the first outer rim member. A central axis passes centrally through the first and second opposite ends of the first central member. A first piezoelectric ceramic material has first and second opposing sides and the first side of the first piezoelectric ceramic material is rigidly affixed to the first flexible annular diaphragm area's first side. A second piezoelectric ceramic material has first and second opposing sides and the first side of the second piezolectric ceramic material is rigidly affixed to the first flexible annular diaphragm area's second side.

Abstract: A micromechanical device having a frequency trimmable, resonant structure, including a semiconductor substrate forming a support frame. First and second flexures flexibly couple and support a structure within the support frame, to permit rotation with a resonant frequency about a first axis which passes through the flexures. First and second elongated openings located proximate the first and second flexures form first and second tension relief beams adjacent the flexures, for providing stress relief of the tensile forces between the resonant structure and the flexures, and for establishing and trimming the resonant frequency of the resonant structure.

Abstract: A drive circuit for use with a capacitive load includes two transistors controlled by a drive voltage and connected to the load through an inductor. A supply voltage is alternately connected and disconnected to the circuit to achieve a resonant transfer of energy from the supply voltage. Energy stored in the load is transferred to the inductor and then back to the load, thereby reversing and augmenting the output voltage across the load and providing an instantaneous output voltage many times the supply voltage. Diodes ensure that the current flows in the proper polarity through the transistors.

Abstract: A support member preferably made of a metal such as cold rolled steel is disposed in a looped configuration and is provided with a gap. A transducer member preferably made of a piezoelectric material such as a ceramic is disposed within the support member. The transducer member is provided with a gap at a position corresponding to the gap in the support member. A closure member made from a suitable springlike material such as an alloy steel is attached to the opposite ends of the support member at the position of the gap as by welding. The closure member extends in a U-shaped configuration into the looped configuration (in section) defined by the support member and the ceramic member. The axial length of the closure member defines the bandwidth of the frequency vibrations generated by the transducer member.

Abstract: A monolithic resonator structure for a vibrating beam force sensor, comprising an accelerometer and pressure transducer, is provided which comprises an outer structure including a mounting structure, a force transfer structure, a plurality of flexure beams extending between the mounting and force transfer structures; and an inner structure including a vibrating beam extending between the mounting structure and the force transfer structure. The monolithic resonator is non-planar in that the outer structure has a thickness greater than said inner structure.

Abstract: A linear ultrasonic motor which presses a rail against an ultrasonic vibrator, which is substantially elliptically vibrating and conducts relative movement, wherein a protrusion or a groove is provided such that the sectional form of the rail is concave, convex, trapezoidal or triangular. Furthermore, the above vibrator is provided with a groove or a protrusion which uniformly abuts the groove or protrusion of the rail. In the linear ultrasonic motor according to the invention, there is no deterioration of responsiveness due to a support mechanism and no unnecessary vibration, so generated noise is small.

Abstract: A low impedance acoustic source suitable for used in down-hole well logging includes a mechanical transformer for impedance matching of the source to the surrounding environment. Elliptically shaped flexible beams are positioned along the long axis of an ellipse, and a pump is oriented along the long axis of the ellipse for driving the flexible beams. In a preferred embodiment the pump comprises first and second stacks of transducers which engage the flexible beams at opposing ends with the two stacks of transducers operating in a push-pull mode of operation. Rigid extension at opposing ends of the flexible beams function as levers in translating the motion of the transducers to the flexible beams. A rigid support rod is positioned along the long axis of the ellipse in engagement with the rigid extensions at fulcrum points, and an adapter associated with each stack of ceramic transducers engages and drives the rigid members about the fulcrum point.

Abstract: A rotation-detecting apparatus includes a U-shaped support member, a rod at least one end of which is held to the support member, a vibrating sheet mounted to the rod, piezoelectric ceramic sheets mounted on the vibrating sheet, a torsion detector for detecting the rotation of the vibrating member relative to the rod, and an oscillator circuit for activating the piezoelectric sheets to vibrate the vibrating sheet. The Coriolis force produced on the vibrating sheet is converted into a twist of the rod and detected.

Abstract: A broadly tuned transducer system for pulse echo ranging systems has a rigid plate, to a planar radiating front surface of which is applied at least one layer of acoustic coupling material having a density intermediate between that of the plate and an atmosphere into which the transducer is to be coupled. Three or more driver assemblies spaced apart in a two dimensional array are ridigly secured to a rear surface of the plate, each assembly having a loading block and a piezoelectric element compressed between the block and the plate. The driver assemblies all have the same resonant frequency on axes perpendicular to the plate and are driven in phase; they occupy not less than one-fifth and not more than four-fifths of the area of the rear surface of the plate, which is rigid enough to prevent the excitement of significant flexural oscillations. The arrangement permits the transducer to have a large planar radiating surface while using quite small piezoelectric elements.

Abstract: A method and arrangement for providing damping of undesired modes of piezoelectric vibrators is disclosed that eliminates the tedious and often inaccurate methods of known mass-loading techniques. Instead, the arrangement relies on physically altering a controlled amount of the piezoelectric material located at a predetermined point to effect the selective damping needed to minimize the undesired responses and to minimally interfere with the desired mode of operation.

Abstract: In the piezoelectric transducer, the elastic member vibrates, being excited by the first electromechanical transducing element. The impedance element on the second electromechanical transducing element is adjusted so that the vibration frequency and the resonance frequency of the elastic member should be almost the same. In the ultrasonic motor using the piezoelectric transducer, the vibration having the same frequency as that of the vibration of the elastic member is applied to the elastic member. This applied vibration has a direction differnt from that of the viration of the elastic member. The applied vibration and the vibration of the elastic member form approximate elliptical vibration, thereby rotating the rotor. The piezoelectric transducer of variable structure can control the resonance frequency in a wide range without electric power.

Abstract: A transducer for a stringed musical instrument incorporating an electrically conductive ground plane, along with a plurality of piezoelectric transducers and a conductive strip. The ground plane, piezoelectric transducers and conductive strip are secured in an elongated unitary structure with the ground plane and conductive strip disposed on opposite sides of the transducers. A conductive shield is disposed about the unitary structure and electrical leads connect to the ground plane and conductive strip, respectively.

Abstract: A method of filtering an AC signal using a piezoelectric beam is provided. A piezoelectric film is formed on a mechanical support and a portion of the piezoelectric film forms a beam which extends beyond the mechanical support so that a cavity is formed underneath the beam, and the beam is free to vibrate in the cavity at a resonant frequency when an acoustic wave is propagated in the piezoelectric layer.A depletion region is formed under a Schottky contact which serves as a drive electrode. An unfiltered AC signal is coupled to the drive electrode thereby establishing an acoustic wave when the unfiltered AC signal comprises a component at the resonant frequency. Surface charge on the piezoelectric film resulting from vibration of the beam allows the resonant frequency component of the unfiltered AC signal to pass through the depletion region. Alternatively, the resonant frequency component can be passed by a tunnel current through the cavity.

Abstract: A vibrating force transducer suitable for use in a pendular accelerometer mprises a flat elongated strip of piezo-electric material having end portions arranged for being securely connected to elements which apply a force to be measured along the direction of elongation when the transducer is in service. The strip is fractionated by slits parallel along the direction of elongation and orthogonal to major faces of the strips into a central beam and lateral beams which are in a common plane, the lateral beams carrying electrode means for flexural vibration in the common plane at a resonance frequency indicative of the value of the force applied to the end portions and the central beam carrying a resistive temperature sensor.

Abstract: A transducer assembly includes a hollow support member disposed in a looped configuration and having an axial opening. A hollow transducer supported within the support member may be made from a piezoelectric material and may be provided with an axial opening corresponding to position to the axial opening in the support member. In one embodiment, the outer surface of the support member may be thinned at spaced positions as by sockets or spaced axial grooves extending partially through the support member. The support member may be thinned at strategic positions to control the vibrational frequency and the frequency bandwidth of the transducer assembly. The thinned portions of the support member may receive a compliant material such as urethane to smoothen the outer surface of the support member. In another embodiment, the hollow interior of the transducer assembly may be filled with a compliant material, such as urethane, which may be provided with air chambers.

Abstract: A piezoelectric vibration generator interconnecting a base and a vibratory conveyor table of a piezoelectrically driven vibratory parts feeder includes a pair of resilient plate members joined together at their lower ends and disposed in a configuration substantially folded about the joint therebetween. The vibration generator of the folded configuration has a relatively small length and hence is capable of reducing the overall height of the vibratory parts feeder. A further advantage attained by the folded vibration generator is that the amplitude of vibrations is not limited depending upon the distance between the base and the vibratory conveyor table.

Abstract: There is disclosed an improved electromechanical resonator for use in multiresonator mechanical bandpass filters. The resonator is constructed using two resonator rods attached to a ceramic transducer which is substantially centrally located. The thus-formed electromechanical resonator resonates at the desired frequency in the third torsional mode, which is characterized by three motional nodes. Support pins are attached at the two outer nodes to provide physical support, and are also used for signal and ground connections, while the ceramic is positioned on or near the center node, which maximizes the achievable electromechanical coupling. Multiresonator mechanical bandpass filters which use such third-mode electromechanical resonators in conjunction with second-mode interior resonators have improved spurious rejection.

Abstract: A direction selective transducer which includes a center mass fixed between two active transducer element stacks and two head masses. The center mass couples the two stacks and allows the ratio of radiation produced by each head mass to be selected as desired by varying the amplitude and phase of drive voltages applied to the stacks. The transducer can also be used as a directional receiver.

Abstract: A monolithic resonator for a vibrating beam accelerometer is provided which comprises an outer structure including a mounting structure, a proof mass structure, a plurality of flexure beams extending between the mounting and proof mass structures; and an inner structure including first and second isolator masses, first and second isolator beams connected to one portion of the isolator masses, respectively, and a vibrating beam extending between other portions of the isolator masses. The monolithic resonator is non-planar in that the outer structure has a thickness greater than said inner structure.

Abstract: An impulse sensor comprises a transducer container vessel of a cylindrical shape including a pair of stocky sections connected to one another by a midsection of a reduced cross section area, a force transmitting member extending from one end of the transducer container vessel and a force receiving member connected to the force transmitting member, wherein two Piezo electric elements are respectively contained in two cavities respectively included in the two stocky sections of the transducer container vessel. Each of the two Piezo electric elements has a pair of electrodes respectively disposed on the two opposite sides of a reference plane including the central axis of the combination of the transducer container vessel and the force transmitting member. Electrical signals supplied from the four electrodes are combined in such a way that the noises generated by the mechanical vibrations are cancelled and signals representing forces experienced by the force receiving member are obtained.

Abstract: An impact detector for use with a grain loss monitor of a harvesting machine includes a damped detector plate member and a transducer associated with a surface of said detector plate member. The detector plate member is provided with signal damping means only around its periphery, whereby a substantial area of the detector plate member is delimited which is void of any signal damping means.

Abstract: A technique is described for tailoring the configuration of electrodes on a piezoelectric beam such that the tendency of the beam to vibrate in a predetermined flexure mode is enhanced. The mode has a predetermined longitudinal strain versus longitudinal position profile. At least two electrodes are mounted on the beam, and the configuration of at least one electrode varies as a function of longitudinal position, such that when a voltage difference is applied between the electrodes, the longitudinal force produced by the electrodes, as a function of longitudinal position, approximates the longitudinal strain versus longitudinal position profile. The configuration may be varied by varying the width of the electrode or the position of the electrode on the underlying beam surface.

Abstract: An apparatus and method to generate high intensity sound having a strong directional characteristic. The apparatus preferably uses a sound element (e.g. piezo sounder) which is capable of generating a high intensity, power efficient sound, but which has poor directional characteristics because of its high frequency (e.g. 3000 Hz). The apparatus drives the sound element with a variable frequency signal which sweeps across the resonant bandwidth of the sound element. The sweep rate of the frequency shift is less than about 1200 Hz which gives the sound a directional characteristic--resulting in periodic bursts of high intensity sound that is strongly directional. The apparatus may be incorporated into a wide variety of applications where high intensity, power efficient, strongly directional sound is desirable.

Abstract: A resonant scanner has at least one torsionally rigid damper located at at least one torsional node point of a torsion bar. At least one node of an unwanted vibrational mode is determined to be at a distinct node point, whereby the damper damps the unwanted vibrations while passing desired torsional oscillations. The damper serves as the only physical coupling of the torsion bar to the housing and damps transmission of vibrations into and out of the scanner. One or both ends of the torsion bar may be configured as the rotor of a motor. The rotor fits within but is not physically coupled to a bobbin coupled to the frame. Two coils are wound on the bobbin at approximate right angles to each other to minimize a cross-coupling between the coils.

Abstract: A device for determining the filling level in a container including an oscillator with two rotational oscillation elements (10, 12) of the same resonance frequency which oscillate oppositely. The oscillation elements (10, 12) are arranged coaxially, have a common rotational axis, masses of the same size, and a common mass center. Both oscillation elements (10, 12) are fixed to a common membrane which serves as a retraction spring, through which a common drive of both oscillation elements (10, 12) is possible.

Abstract: A linear motor is arranged to have two legs each of which have a different resonance frequency, when one of the legs is induced to resonate by applying a vibration having a frequency which corresponds to the resonance frequency of one of the legs, to the chassis of the motor, the motor proceeds in a first direction, while when a vibration having a second frequency which corresponds to the resonance frequency of the other leg is applied, the motor is propelled linearly in the other direction.

Abstract: A method of testing piezo-electric transducers includes locating one end (11) of a rod (10) of solid material over the active head (20) of the transducer, the rod (10) simulating the normal acoustic impedance presented to the transducer by the normal medium, in which the transducer is intended to operate, energizing the transducer and detecting the acoustic wave propagated through the rod at the other end of the rod. A loading rod for use in testing a piezo-electric transducer is an elongated solid body so dimensioned as to simulate the normal operating acoustic impedance presented to a piezo-electric transducer to be tested.

Abstract: A solid sensor, for sensing a physical parameter such as pressure, comprises a resonantly vibratable beam formed across a cavity in a substrate by micro-machining, and arranged such that changes in the parameter vary its resonant frequency. The beam either consists of or has deposited on it a material exhibiting piezo-electric effect, so that vibration of the beam can be excited by using the effect. This is achieved using light, either by forming a photodiode in the substrate in or near the beam, so that illuminating the photodiode causes a voltage to be applied to the beam, or, in the case where the piezo-electric material exhibits surface piezo-electric effect, by directly illuminating the beam.

Abstract: A vibrating fiber optic display unit is provided for use as an aircraft pilot display unit and for overcoming the problem of manually adjusting the display unit due to temperature changes. The display unit has a fiber optic ribbon having a plurality of fibers which form a display pattern at the free ends of the fibers during vibration of the fiber optic ribbon. The ribbon has light emitting diodes for the fibers. A microprocessor provides signals to the diodes for forming light dots in the display pattern. A piezo film transducer is mounted on the ribbon. Drive means vibrates the ribbon. An optocoupler has a shutter portion mounted on the ribbon. A ribbon oscillator network receives signals from the optocoupler and from the piezo film transducer and provides signal to the drive means, whereby the ribbon is vibrated at its natural frequency, and whereby the drive means automatically adjusts to changes in the ribbon natural frequency due to temperature change.

Abstract: In order to implement a vibrating beam accelerometer, preferably in a dual beam configuration, a monolithic piezoelectric structure which includes at least a first mounting surface, a second mounting surface spaced therefrom and between the mounting surfaces and coupled thereto a vibrating beam, is provided. The two mounting surfaces are connected to each other by flexures so that relative movement between them is possible. This structure results in a closed path from mounting surface to vibrating beam to mounting surface avoiding problems present in prior art devices in which there were joints at three different points within the closed path.