Showing papers on "Transducer published in 1987"

Dynamic piezoelectric translation devices

Abstract: The principle of inertial sliding of a platform on a periodically accelerated support is exploited for the design of a piezoelectric fine‐positioning device. The device provides step sizes of 0.04–0.2 μ, speeds of up to 0.2 mm/s, and practically unlimited translation range. It is powered by a sawtooth electric waveform of 60–300‐V amplitude and useable for loads of up to 1 kg and probably even more. Mechanical parts and driver electronics are extremely simple, reliable, and easy to operate.

Method for removing cellular material with endoscopic ultrasonic aspirator

Abstract: A method and apparatus for endoscopic removal of compliant biological tissues utilizing an endoscopic ultrasonic aspirator comprising irrigation and aspiration means, a piezoelectric ultrasonic transducer, a first resonator such as a half-wave stepped velocity transformer, a probe including a second resonator such as a constant-stress velocity transformer, a blunt or modified working tip of open channel means or restricted tubular means for application of ultrasonic energy to cellular material, and a capacitive fluid sensor to detect the presence of irrigation fluid adjacent these transformers within the instrument. The surgery is advantageously performed by operating the transducer in the 10-20 kHz range to achieve maximum cavitation of the intracellular fluids in the tissues to be removed.

Apparatus and process for reagent fluid dispensing and printing

Abstract: This invention relates to a system for printing and dispensing chemical reagents in precisely controlled volumes onto a medium at a precisely controlled location. A jetting tube, comprising an orifice at one end and a fluid receiving aperture at the other end, is concentrically mounted within a cylindrical piezo-electric transducer. The fluid receiving aperture is connected to a reservoir containing a selected reagent by means of a filter. The reservoir may be pressurized by a regulated air supply. An electrical signal of short duration is applied to the transducer. The pulse causes the transducer and the volume defined by the jetting tube to expand, thereby drawing in a small quantity of reagent fluid. The cessation of the pulse causes the transducer and the volume of the jetting tube to de-expand, thereby causing at least a substantially uniformly sized droplet of reagent fluid to be propelled through the orifice. The droplet may be directed to impact a printing medium or collected in a dispensing recepticle.

Systems for measurement and analysis of forces exerted during human locomotion

Abstract: Systems including piezoelectric sensor elements advantageously mounted between supporting hard plastic material of various types or other mechanically similar materials. The sensor can further be supported by backup plate structures. Some backup plates show full shoe coverage and others show partial sole coverage. Detachable mounting formed by mechanically interengaging parts allow transducer inserts to be made in a modular manner for use in different sensor shoes or sensor insole pads, thus allowing many more patients to be analyzed and treated through use of the invention. Also disclosed is a digital charge signal integrator circuit.

System of therapeutic ultrasound and real-time ultrasonic scanning

Abstract: A system is described for obtaining in real-time cross-sectional and 3-dimensional images of a body under study using ultrasonic energy. A piezoelectric transducer is positioned to emit ultrasonic energy and receive echo pulses. The transducer is electronically swept or physically rotated to produce a series of sectored scan planes which are separated by a known angular distance. The echo pulses are processed to produce an ultrasonic image in pseudo 3-dimensional display. By using data from one scan plane, processed as a B-scan image, cross-sectional data can be obtained. Such is combined in a display with an overlay to visually portray the object and positioning information or comparative data. The system is combined with a computer for data analysis and a therapeutic transducer for treatment.

In vivo registration of Achilles tendon forces in man. I. Methodological development.

Abstract: Mechanical behavior of muscle and its control is largely unknown under normal movement conditions. The present report deals with the methodological development to record directly in vivo forces from the human achilles tendon (AT) when the subjects perform normal movements ranging from slow walking to maximal sprinting and jumping. The development began with animal experiments, which dealt with the transducer design, surgical operation procedures, and duration of implantation. The first human experiment utilized an E form transducer implanted around the AT under local anesthesia. The transducer was kept in situ for 7 days, and on the 8th day recordings were made on simple plantar flexion movements and during slow walking. Further development led to final selection of a "buckle"-type transducer, and the measurements can be made immediately after operation and they usually last 2-3 h. The AT transducer can be calibrated by placing the subject in a prone position on to a calibration table. His operated foot was placed in a special shoe, the axis of which coincided with that of the ankle joint. A pulley system with known weights was used to dorsiflex the foot. Taking into consideration the geometrical arrangement of the AT transducer, axis of rotation, and the pulley system, the exact values of AT forces could be calculated. The actual measurements incorporate the use of EMG recordings of the leg extensor muscles and various external force measurements, such as long force platform or oscillating ergometers. The transducer is removed immediately after the measurements and the subjects recover.

Apparatus for optically detecting an extraneous matter on a translucent shield

Abstract: An apparatus for optically detecting the attachment state of extraneous matters to a translucent shield member. The optically detecting apparatus comprises a light-emitting unit having a plurality of light-emitting elements each emitting a light ray toward the translucent shield member, a photoelectric transducer unit having a plurality of transducer elements each receiving each of the light rays reflected on the translucent shield member, and a data processing unit coupled to the transducer unit. The transducer unit generates detection signals corresponding to the quantities of the received light rays and the data processing unit successively compares the level of each of the detection signals with a predetermined level to produce binary signals in accordance with the results of the comparison so that a binary signal pattern is defined at the respective transducer elements. The data processing unit determines the attachment state of the extraneous matters to the translucent shield member by comparing the defined binary signal pattern with a reference pattern.

Ultrasound therapy device.

Abstract: An ultrasound therapy device is provided which maintains a selected constant electrical drive power to a transducer regardless of the load on said transducer by means of an analog servo feedback circuit. The device is operable in either a continuous or pulsed mode and if operated in the pulsed mode, both the pulse period and the pulse duration can be selected by the operator. Circuitry is provided to prevent the operator from selecting a pulse duration greater than the selected pulse period. Touch pad input switches may be used to input values of the operating parameters, and the chosen parameters may be displayed on digital readouts on the front panel of the device.

Vibration apparatus preferably for endoscopic ultrasonic aspirator

Abstract: A method and apparatus for endoscopic removal of compliant biological tissues utilizing an endoscopic ultrasonic aspirator comprising irrigation and aspiration means, a piezoelectric ultrasonic transducer, a first resonator such as a half-wave stepped velocity transformer, a probe including a second resonator such as a constant-stress velocity transformer, a blunt or modified working tip of open channel means or restricted tubular means for application of ultrasonic energy to cellular material, and a capacitive fluid sensor to detect the presence of irrigation fluid adjacent these transformers within the instrument. The surgery is advantageously performed by operating the transducer in the 10-20 kHz range to achieve maximum cavitation of the intracellular fluids in the tissues to be removed.

Sensor conditioning method and apparatus

Abstract: An adaptable method and apparatus for calibrating and conditioning sensor output to conform to a desired transfer function is provided. In one form, the invention allows use of a sensor system having nonlinear output characteristics when measuring a physical quantity and provides a response which varies linearly to changes in the physical quantity. In the calibration phase, a look-up table is built based on inputs from the sensor system and a reference transducer which behaves in the desired fashion to changes in the physical quantity. In the operation phase, the sensor system measures the unknown physical quantity and enters the look-up table to determine a corresponding reference value. Thus, the present invention adapts a sensor system to an application without restrictive considerations to individualized operating performance of the sensor system or environment of the application.

Portable ultrasonic probe

Abstract: A hand-held portable ultrasonic scanning probe for use with energizing and receiving means for imaging sections of a body includes a fluid-filled enclosure coupled to a handle portion which houses a DC drive motor The output shaft of the drive motor is directly coupled to a level wind drive screw A holder assembly incorporating a pawl which coacts with the drive screw and a plano-concave transducer moves back and forth across the drive screw as a result of the DC motor output shaft rotation The linear travel of the transducer creates a linear scan thereby eliminating the diagnostic imaging problems of sector scans

IC-Processed piezoelectric microphone

Abstract: A miniature diaphragm pressure transducer having sensitivity to acoustic signals at the level of conversational speech has been fabricated by combining micromachining procedures (to produce a thin silicon-nitride diaphragm) with ZnO thin-film processing. The sensor consists of a patterned ZnO layer (which acts as a piezoelectric transducer) deposited on a thin square micromachined diaphragm made of LPCVD silicon nitride. The diaphragm, 2 µm in thickness, is the thinnest yet reported for a piezoelectric readout structure of relatively large area (3 × 3 mm2). The transducer shows an unamplified response of roughly 50 µV/µbar when excited by sound waves at 1 kHz with the variation of the sensitivity from 20 Hz to 4 kHz being approximately 9 dB. These results are obtained using a 0.1-mm-wide annular pattern that measures 3.6 mm in circumference.

Multipoint pressure-sensing catheter system

Abstract: A capacitive pressure sensor suitable for making highly sensitive, low pressure measurements is disclosed. The sensor may be mounted into a 0.5 mm OD catheter suitable for multipoint pressure measurements from within the coronary artery of the heart. The sensor employs a transducer which consists of a rectangular bulk silicon micro-diaphragm several hundred microns on a side by two microns thick, surrounded by a supporting bulk silicon rim about 12 microns thick. Both the diaphragm and the rim are defined by a double diffusion etch-stop technique. The transducer fabrication process features a batch wafer-to-glass electrostatic seal followed by a silicon etch, which eliminates handling of individual small diaphragm structures until die separation and final packaging. An addressable read-out interface circuit may be used with the sensor to provide a high-level output signal, and allows the sensor to be compatible for use on a multisite catheter having only two electrical leads.

Telemetry system for water and energy monitoring

Abstract: A water quality monitor computer (10) repeatedly accesses transducers (12) which monitor physical properties of a water system, such as total dissolved solids, pH, and the like. The water quality monitor computer determines from the monitored water conditions when bleeding or the addition of water treatment chemicals is required. An energy and water management computer (20) periodically accesses the water quality computer and operates valves and pumps (22) to bleed the system or add chemicals, as is appropriate. The management computer further monitors the quantity of chemical supplies on hand with chemical inventory transducers (24), the amount of electrical energy consumed with kilowatt transducer (28) and the like. The energy and water management computer controls energy usage and stores energy and chemical consumption data in a memory (40). A polling station (B) selectively polls one or more of the remote stations to change the energy or water management programs or to receive data and water system physical property data therefrom. One of the polling stations includes a central computer (250) which polls each remote station daily. The central computer causes a printer ( 254) to generate daily reports indicating abnormal conditions at each remote station and to generate shipping orders and invoices for replacement chemicals as replacement becomes necessary. The central polling computer also generates a monthly report of energy and chemical consumption, water treatment system physical property data, energy savings, and the like.

Capsulectomy cutting apparatus

Abstract: A capsulectomy apparatus which comprises a console, a handpiece and a needle. The handpiece operates from a vibrating transducer which drives a rod within the sleeve of the needle for actively engageing the anterior lens capsule which is to be severed. The head of the needle which engages and cuts the anterior lens capsule of the eye has a specific angular relationship with the rod within the needle. Also, the cutting edges and surfaces associated with the head of the needle have a specific configuration for enhancing the cutting quality of the apparatus. The needle is disposable and specifically configured to be removeably affixed to the handpiece.

Portable electro-therapy system

Abstract: A portable non-invasive apparatus for electro-therapeutic stimulation of tissue and bone healing readily worn or carried by a patient, capable of generating an energy-efficient signal coacting with a suitable transducer of the signal, thereby realizing portability and stimulating tissue and bone healing.

Linear suction control system

Abstract: A linear suction control system 10 includes a linear solenoid valve 11 which exhibits a flow through rate having a known proportional relationship with the current through the solenoid 30. Regulated fluid pressure 12 is fed through the linear solenoid valve 11 to a venturi-type pressure vacuum converter 17. The resulting vacuum is proportional to the flow rate through the valve 11 and thus to the current through the solenoid 30. A transducer 16 samples the vacuum output and produces a signal fed to a differential amplifier 17. The signal is compared in negative feedback fashion with a variable input voltage set by a potentiometer 18 or other variable voltage source, so that the transducer signal tracks the voltage source signal. The voltage source can comprise a potentiometer 18 actuated by a foot switch 19 or the like, so that angular position of the foot switch 19 relates directly and predictably to the vacuum output of the converter 13. The linear solenoid valve 11 includes an electromagnetic coil 30 arranged to translate a valve member 36, with an elastic member 35 biasing the valve member closed with a generally linear restoring force.

Biomedical pressure transducer

Abstract: A biomedical transducer which is useful for interposing between a tissue and apparatus or another tissue or organ which is applying pressure to the tissue, in order to estimate the pressure applied to a selected area of the tissue. The biomedical pressure transducer comprises: a first flexible layer carrying at least one electrical contact; a second flexible layer carrying at least one electrical contact and cooperating with the first flexible layer to define a pressurizable chamber wherein the contacts are normally touching when the chamber is not pressurized; and pressure estimation means for selectably pressurizing the pressurizing chamber so as to move at least one of said flexible layers sufficiently to separate the electrical contacts, and for indicating the lowest selected pressure at which the contacts are separated.

Automatic control system for filling beverage containers

Abstract: An automatic, ultrasonic system for controlling the filling of different sizes of beverage containers which may or may not contain various quantities of ice. The system includes a transducer assembly and a control module, both preferably connected to a beverage dispenser valve assembly. The transducer assembly includes a pair of piezo-electric crystals for separately transmitting and receiving ultrasonic wave energy from the grate, the cup lip, the top of any ice in the cup, and the rising liquid level. The control module includes a microcomputer and associated circuitry.

A Stress State Transducer for Soil

Abstract: Atransducer was developed that measured normal pressures in six predetermined directions to provide data for mathematically determining the complete stress state in soil. The stress state transducer was evaluated under hydrostatic loading in both a sand and a clay. All six sensing elements registered within 6% of the applied pressure.

SAW Temperature Sensor and Remote Reading System

Abstract: A system for remotely reading a SAW temperature sensor has been adapted from an existing, commercially available personnelherchandise detector system. The SAW sensor is a Lithium Niobate wafer with an inter-digital transducer (IDT) which is directly connected to a small transducer which is directly connected to a small microwave antenna and two reflectors. The reading system is a special Fhl radar. The FM electromagnetic signal is transmitted by the system and picked up by the small antenna that is connected to the IDT and is subsequently, converted into a surface acoustic wave in the Lfib03 wafer, reflected by the reflectors, converted back to an electromagnetic wave and returned to the FM radar. The acoustic velocity varies as a function of the ambient temperature and results in varying time delay of the echoes, which is detected by the system. The resolution and accuracy of such a system arr investigated theoretically and experimentally. The operating principle is also suitable for other remote reading SAW sensors.

Random artificially perturbed liquid apparatus and method

Abstract: A frequency-stabilized oscillator is frequency modulated by band-limited random varying signals used to drive a suitable transducer randomly to and artificially perturb fluid jets in an electrostatic fluid jet applicator. Such random artificial pertubation is desirable (especially with longer cross-machine orifice plates) so as to obscure printing irregularities caused by standing wave or other phenomena. However, such random variations are best made with respect to a highly stabilized center frequency.

Vibration wave motor

Abstract: A vibration wave motor for driving a movable member by a travelling vibration wave generated by applying a periodic signal to an electro-mechanical energy transducer element such as an electrostrictive device or piezoelectric device is disclosed. A drive status of the vibration wave motor is detected, a phase difference between the detected signal and the periodic signal applied to the transducer element is detected, a frequency of the periodic signal is selected such that the phase difference is equal to a predetermined constant and the vibration wave motor is driven in a resonance state.

Electropneumatic transducer system

Abstract: A temperature compensation circuit is provided which can be used for span temperature compensation in an electropneumatic transducer system and which includes a constant current generator circuit coupled to a bridge of piezo resistances in a pressure transducer to supply a constant current through one piezo resistance of the bridge to common. The Electropneumatic Transducer System includes a zeroing circuit, a voltage chopping circuit, a linearity correction circuit, a low-current shut-off circuit, and a high-current shut-off circuit to provide hard turn-ons and hard turn offs of the system at the lower and upper ends of the pressure output range or span. The Electropneumatic Transducer System also includes a voltage railsplitting circuit arrangement to minimize the operating currents and voltages. With these features, the Electropneumatic Transducer System is particularly adapted for use in hazzardous combustible atmospheres where Intrinsic Saftey and accuracy are required.

Ultrasonic fuel quantity gauging system

Abstract: A method of measuring aircraft fuel quantity and density in a fuel container using an ultrasonic transducer; a stillwell liquid fuel; a computer control, an indicator and an altitude sensor. The computer control includes a central processing unit connected to each of the ultrasonic transducers. The altitude sensor is connected to the central processing unit. The indicator means is connected to the central processing unit. The stillwell is supported by the container. Each ultrasonic transducer is supported within the stillwell by the container. The liquid fuel is supported within the container. An ultrasonic signal is transmitted from the transducer within the stillwell. The reflected ulrasonic signal is received by the transducer within the stillwell. The round-trip time period from sending to reciving the signal is measured. The quantity of fuel in the container is determined from the round-trip time period and stored data on the container volume in the central processing unit.

Ultrasonic heating apparatus and method

Abstract: A method and apparatus for the treatment of tumors by heating with ultrasonic energy. A transducer assembly is provided in a housing having a refractive assembly disposed between the tumor and the transducer. The refractive assembly moves with respect to the transducer assembly. The refractive assembly includes one or more refractive elements. The refractive assembly is interchangeable to provide treatment of different types of tumors using the same transducer assembly and housing. The refractive assembly may focus, deflect or diffuse the ultrasonic energy depending on the arrangement of elements. Motion of the refractive assembly relative to the tumor results in a time-averaging spatial deposition pattern which is more highly uniform due to the averaging of maxima and minima which occurs in the near field.

Range Finding and Surface Characterization Using High-Frequency Air Transducers

Abstract: The design and applications of high-frequency piezoelec- tric air transducers are described. Two types of thickness mode air transducers are designed and fabricated using newly synthesized acoustic matching layers with an acoustic impedance as low as 0.3 Mrayls. The insertion losses of these transducers are improved by 32- 45 dB compared to that of the transducer without a matching layer. Use of a l-MHz double matching layer transducer with a good RF pulse response for range finding has revealed that the measurement range accuracy is of the order of 0.1 mm. For surface profile and defect mea- surements of solid objects, a focused transducer with a single matching layer is found suitable due to its small focal spot diameter of 1.3 mm and range accuracy of 0.1 mm. Other applications described here are the analysis of a cloth surface state using the acoustic signals propa- gating along the cloth surface and passing through the cloth. air transducers mentioned above. This paper describes the design of these transducers and their applications to range finding, profile measurement of solid objects, and surface state measurement of cloth.

Design and characterization of a high temperature fiber-optic pressure transducer

Abstract: We have measured the pressure response of a high temperature pressure transducer fabricated from a super alloy. This transducer contains a microbend fiber-optic sensor to measure diaphragm deflection and a reference fiber to help reduce light source fluctuations caused by perturbations in the fiber leads. The transducer was characterized at pressures up to 22.8 MPa and temperatures to 430°C. The experimental data taken at constant temperature shows a 0.58 percent (of full scale pressure) minimum deviation between the fiber-optic pressure transducer output and output of a calibrated gage pressure transducer. Over the entire temperature range of 20-430\deg C, the fiber-optic pressure transducer output exhibits a 1.2-percent (of full scale pressure) maximum deviation from calibrated pressure.

Coupler for ultrasonic transducer probe

Abstract: A coupler for use between an ultrasonic transducer probe and a sample to be examined thereby to keep the ultrasonic transducer probe and the sample spaced a prescribed distance from each other includes an acoustic lens in an area through which a ultrasonic signal is to pass from the ultrasonic transducer probe. The acoustic lens allows the focusing point of the lens of the ultrasonic transducer probe to be shifted to a desired position. Since the ultrasonic transducer probe and the sample are spaced from each other by the coupler, the image of an observed region of the sample can be positioned in a wide field of view on a screen.

Pressure sensor with improved capacitive pressure transducer

Abstract: A pressure sensor comprises an improved capacitive pressure transducer having a first capacitor plate secured to a limited portion of a first surface of a relatively rigid ceramic substrate and having a diaphragm with an electrically conductive surface forming a second capacitor plate, the diaphragm being secured to the ceramic substrate at a location spaced inwardly from the periphery of that first substrate surface for disposing the second capacitor plate in spaced, overlying relation to the first capacitor plate to be movable in response to applied pressure for varying the capacitor formed by the plates. Support means bear against opposite surfaces of the ceramic substrate at the periphery of the substrate for mounting the transducer with the diaphragm thereof substantially free of mounting stresses to be exposed to a pressure force in a pressure zone to be monitored.