scispace - formally typeset
Search or ask a question

Showing papers on "Transducer published in 1997"


Patent
11 Mar 1997
TL;DR: A biosensing transponder for implantation in an organism including a human comprises a biosensor for sensing one or more physical properties related to the organism after the device has been implanted, including optical, mechanical, chemical, and electrochemical properties as mentioned in this paper.
Abstract: A biosensing transponder for implantation in an organism including a human comprises a biosensor for sensing one or more physical properties related to the organism after the device has been implanted, including optical, mechanical, chemical, and electrochemical properties, and a transponder for wirelessly transmitting data corresponding to the sensed parameter value to a remote reader. Disclosed embodiments utilize temperature sensors, strain sensors, pressure sensors, magnetic sensors, acceleration sensors, ionizing radiation sensors, acoustic wave sensors, chemical sensors including direct chemical sensors and dye based chemical sensors, and photosensors including imagers and integrated spectrophotometers. The transponder includes an energy coupler for wirelessly energizing the device with a remote energy source, and a control circuit for controlling and accessing the biosensor and for storing identifying data. The energy coupler can be an inductive circuit for coupling electromagnetic energy, a photoelectric transducer for coupling optical energy, or a piezoelectric transducer for coupling ultrasonic energy. The control circuit can be configured to delay, either randomly or by a fixed period of time, transmission of data indicative of the sensed parameter value to thereby prevent a data collision with an adjacent like device. Methods for using an implantable biosensing transponder include the steps of associating the device with an implant, including temporary implants, prostheses, and living tissue implants, physically attaching the device to a flexible catheter, sensing parameter values in an organism, and transmitting data corresponding to the sensed parameter values to a remote reader.

871 citations


Patent
03 Feb 1997
TL;DR: In this paper, a three way valve controlled by the circuit connected the duct transducer to gas metered to the cavity is used to determine the rate of pressure change after the valve connection.
Abstract: A method and apparatus detect occlusion in a tube to a passage into a body cavity. An argon gas supply output received by plural selectable flow orifices so one or more of the orifices delivers predetermined metered gas. A duct with a volume of gas selectively provides metered gas to the passage. The tube connects the passage and the duct periodically so a duct pressure transducer can signal. A circuit tests signals of tube equalization with a back pressure. A three way valve controlled by the circuit connects the duct transducer to gas metered to the cavity. The valve alternatively connects the duct transducer to the tube to equalize the tube with metered gas to the back pressure. A monitor of the signals determines the rate of pressure change after the valve connection. The monitor indicates pressure equalization after a timed interval with a timer to establish intervals for checking back pressure. The monitor remembers cavity pressure before connecting the duct transducer to the metered gas and compares remembered pressure with the back pressure after each test interval. Plural orifices provide specific gas flows to the handset and the valve for equalizing them with metered gas as a function of the flow. Connecting plural orifices to meter gas output, delivering the metered gas output with one or more of the orifices, containing the volume of gas in the duct connected to the metered gas output, selectively connecting the duct to the passage, connecting the tube to the passage with the duct and the transducer to periodically signal are steps. Coupling the circuit to one or more orifices, equalizing the tube with back pressure in response to the signals and coupling the transducer to the metered gas output are steps. Connecting the duct transducer to the tube permits periodic back pressure equalization with metered gas output, signaling the monitor with the transducer, determining periodically the rate of pressure change in the tube by the transducer, indicating in the interval with the monitor equalized tube pressure and remembering cavity pressure before connecting the metered gas output and the transducer for intervals and providing specific flows to the handset and the valve to make the back pressure a function of the selectable flow are steps.

620 citations


Patent
07 Apr 1997
TL;DR: In this paper, an apparatus for interfacing the movement of a shaft with a computer includes a support, a gimbal mechanism having two degrees of freedom, and three electromechanical transducers.
Abstract: An apparatus for interfacing the movement of a shaft with a computer includes a support, a gimbal mechanism having two degrees of freedom, and three electromechanical transducers When a shaft is engaged with the gimbal mechanism, it can move with three degrees of freedom in a spherical coordinate space, where each degree of freedom is sensed by one of the three transducers A fourth transducer can be used to sense rotation of the shaft around an axis The method includes the steps of defining an origin in 3-dimensional space, physically constraining a shaft in the 3-dimensional space such that a portion of the shaft always intersects the origin and such that a portion of the shaft extending beyond the origin defines a radius in a spherical coordinate system, transducing a first electrical signal related to a first angular coordinate of the radius with a first transducer, transducing a second electrical signal related to a second angular coordinate with a second transducer, transducing a third electrical signal related to the length of the radius with a third transducer, and coupling the transducers to a computer

503 citations


Patent
27 Feb 1997
TL;DR: In this article, the relative movement between respective frames of the image data is automatically estimated by a motion estimator, based on frames of data from the tracking arrays, and features of the target remain within the image planes of the tracking array.
Abstract: An ultrasonic imaging system includes an ultrasonic transducer having an image data array and a tracking array at each end of the image data array. The tracking arrays are oriented transversely to the image data array. Images from the image data array are used to reconstruct a three-dimensional representation of the target. The relative movement between respective frames of the image data is automatically estimated by a motion estimator, based on frames of data from the tracking arrays. As the transducer is rotated about the azimuthal axis of the image data array, features of the target remain within the image planes of the tracking arrays. Movements of these features in the image planes of the tracking arrays are used to estimate motion as required for the three-dimensional reconstruction. Similar techniques estimate motion within the plane of an image to create an extended field of view.

483 citations


Patent
24 Dec 1997
TL;DR: An acoustic touch sensing device, comprising a substrate, having a surface; and an acoustic wave transducer (11, 12), transducing a bulk wave in the substrate propagating through the substrate along an axis intersecting the surface, wherein energy of bulk wave is coupled to a wave having a converted wave mode with energy at the surface and propagating along the surface by the gratings transducers (5a, 5b, 8a, 8b) as discussed by the authors.
Abstract: An acoustic touch sensing device, comprising a substrate, having a surface; and an acoustic wave transducer (11, 12), transducing a bulk wave in the substrate propagating through the substrate along an axis intersecting the surface, wherein energy of bulk wave is coupled to a wave having a converted wave mode with energy at the surface and propagating along the surface by the gratings transducers (5a, 5b, 8a, 8b).

319 citations


Patent
28 Nov 1997
TL;DR: In this article, the position and orientation of an ultrasound transducer are tracked in a frame of reference by a spatial determinator, which is used to generate processed images from the images acquired by the transducers.
Abstract: The present invention provides a system and method for visualizing internal images of an anatomical body. Internal images of the body are acquired by an ultrasound imaging transducer. The position and orientation of the ultrasound imaging transducer is tracked in a frame of reference by a spatial determinator. The position of the images in the frame of reference is determined by calibrating the ultrasound imaging transducer to produce a vector position of the images with respect to a fixed point on the transducer. This vector position can then be added to the position and orientation of the fixed point of the transducer in the frame of reference determined by the spatial determinator. The position and orientation of a medical instrument used on the patient are also tracked in the frame of reference by spatial determinators. The position and orientation of the instrument is mapped onto the position and orientation of the images. This information is used to generate processed images from the images acquired by the transducer. The processed images are generated from a view spatially related to the position of the instrument. The system is expandable so that more than one instrument and more than one transducer can be used.

313 citations


Patent
07 Apr 1997
TL;DR: In this paper, a transducer is mounted on a sliding window of an aerodynamically supported slider with an air bearing surface, and a temperature sensor is employed to measure the slider operating temperatures and provide a temperature sensitive input to the temperature control circuit.
Abstract: A device for reading and recording magnetic data includes an aerodynamically supported slider with an air bearing surface, and a transducer mounted to the slider for movement toward and away from the air bearing surface responsive to changes in the slider operating temperature. In one embodiment, the transducer movement is primarily due to a difference in thermal expansion coefficients between a transducing region of the slider incorporating the transducer, and the remainder of the slider body. In another embodiment, a strip of thermally expansive material is incorporated into the slider near the transducer to contribute to the displacement by its own expansion. A temperature control circuit, coupled to the strip of thermally expansive material or to a resistance heating element on the slider, employs a variable current source to control the slider temperature and transducer displacement. Nominal slider operating temperatures can be set to achieve a predetermined transducer flying height, to compensate for variations in flying heights among batch fabricated sliders. Optionally, a temperature sensor can be employed to measure the slider operating temperatures and provide a temperature sensitive input to the temperature control circuit.

267 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated defect detection methods for rolling element bearings through sensor signature analysis, specifically the use of a new signal processing combination of the high-frequency resonance technique and adaptive line enhancer.

256 citations


Journal ArticleDOI
TL;DR: In this article, the moonie transducers were modified systematically by using finite element analysis combined with experimental techniques, and a new transducer design was developed with larger displacement, larger generative forces, and more cost-effective manufacturing.
Abstract: This paper presents original results obtained in the development of the moonie-type transducers for actuator applications. The moonie-type actuators fill the gap between multilayer and bimorph actuators, but its position-dependent displacement and low generative force are unacceptable for certain applications. The moonie transducers were modified systematically by using finite element analysis combined with experimental techniques. A new transducer design, named "cymbal transducer", was developed with larger displacement, larger generative forces, and more cost-effective manufacturing. The cymbal transducers consist of a cylindrical ceramic element sandwiched between two truncated conical metal endcaps and can be used as both sensors and actuators. The cymbal actuator exhibits almost 40 times higher displacement than the same size of ceramic element. Effective piezoelectric charge coefficient, Eff. d/sub 33/, of cymbal is roughly 40 times higher than PZT itself.

241 citations


Patent
14 Feb 1997
TL;DR: In this article, a field transducer for determining position or orientation in a medical instrument locating system is placed at an arbitrary position and orientation with respect to a feature (62) of the instrument.
Abstract: A field transducer (30) for determining position or orientation in a medical instrument locating system is placed at an arbitrary position or orientation with respect to a feature (62) of the instrument (46). The transducer (30) may be attached at an arbitrary location on the instrument (46), or the instrument (400, 404) may be bent as desired by the user. A transform relating position or orientation of a feature of the instrument to position or orientation of the transducer is obtained in a calibration cycle. A field transducer may be part of a disposable unit which is irrevocably altered when used with an instrument, so that the unit cannot be reused.

228 citations


PatentDOI
TL;DR: In this article, a transducer is mounted on a silicon die attached to a flexible circuit, and a jacket is designed to protect the transducers from light and electromagnetic interferences.
Abstract: A housing for shielding a transducer of the type mounted on a silicon die attached to a flexible circuit. The housing provides a jacket which protects the silicon die from physical damage. The jacket, in cooperation with the top and bottom cups, further provides a shield for the silicon die from light and electromagnetic interferences. An acoustic port located on the top portion of the jacket furnishes the means by which acoustic energy enters the jacket to contact the transducer. A back cavity, formed between the bottom cup and the silicon die, serves as the acoustic pressure reference which allows the microphone to function properly.

Patent
Jean M. Beaupre1
09 Jul 1997
TL;DR: In this article, a transducer assembly adapted to vibrate at an ultrasonic frequency is used to propagate the ultrasonic vibration from a first-end to a second-end.
Abstract: The present invention relates to surgical devices. A surgical instrument in accordance with the present invention includes a transducer assembly adapted to vibrate at an ultrasonic frequency. An end effector is adapted to receive ultrasonic vibration from the transducer assembly and to propagate the ultrasonic vibration from a first end to a second end. The end effector is rotatable with respect to the handpiece assembly while the transducer assembly vibrates at the ultrasonic frequency. A method of applying ultrasonic energy to tissue of a patient is also provided. The method includes the steps of providing a handpiece assembly carrying an acoustic assembly having a transducer assembly and an end effector, and energizing the transducer to cause the end effector to vibrate. The method further includes the steps of rotating the end effector with respect to the handpiece assembly while the transducer assembly is vibrating, and contacting the tissue of the patient with the end effector.

Journal ArticleDOI
TL;DR: In this paper, the authors present the data of a mode-I fracture experiment where the samples are broken under imposed pressure and the acoustic emission of microfractures before the breakup of the sample is registered.
Abstract: We present the data of a mode-I fracture experiment. The samples are broken under imposed pressure. The acoustic emission of microfractures before the breakup of the sample is registered. From the acoustic signals, the position of microfractures and the energy released are calculated. A measure of the clustering of microfractures yields information about the critical load. The statistics from energy measurements strongly suggest that the fracture can be viewed as a critical phenomenon; energy events are distributed in magnitude as a power law, and a critical exponent is found for the energy near fracture. [S0031-9007(97)04346-9] PACS numbers: 62.20.Mk, 46.30.Nz Fracture is a problem which has recently received a lot of attention in the physics community [1–3]. It is troublesome to calculate the force needed to break a heterogeneous material. Instead, it is customary to resort to tests involving the destruction of the sample. Therefore it is interesting to provide additional knowledge about cracks by studying the events that occur prior to the fracture. Besides , despite great experimental and numerical efforts [1– 6], many aspects still remain unclear about the fracture process itself. Conceptually simple models, such as per-colation [6] and self-organized criticality [7], are attractive but often fail to convey the complex phenomenology observed. The main motivation of this work is to understand if these models can reproduce the main features of crack formation. We report here some experimental results that may help to gain valuable information in that direction. Our main tool is the monitoring of the microfractures, which occur before the final breakup, by recording their acoustic emissions (AE). Because of its ability to pinpoint the emission source, this technique has been widely used in seismography and to map the nucleation of fractures [8]. From these signals, we have also obtained the acoustic energy of each microfracture, which is a fraction of the total energy released. The behavior of the energy just before fracture is a good parameter to compare with the above mentioned models. In order to avoid noise, we have designed a setup in which there are no moving parts, the force being exerted by pressurized air (see Fig. 1). A circular sample having a diameter of 22 cm and a thickness of 5 mm is placed between two chambers between which a pressure difference P ෇ P 2 2 P 1 is imposed. The deformation of the plate at the center is bigger than its thickness, then the load is mainly radial [9,10]. Therefore, the experience can be thought of as a mode-I test with circular symmetry. The pressure difference P supported by the sample is slowly increased and it is monitored by a differential transducer. This measure has a stability of 0.002 atm. The fracture pressure for the different tested materials ranges from 0.7 to 2 atm. We regulate P by means of a feedback loop and an electronically controlled valve which connects one of the two chambers to a pressurized air reservoir. The time taken to correct pressure variations (about 0.1 s) is smaller than the characteristic time of the strain rate. An inductive displacement sensor gives the deformation at the center of the plate with a precision of about 10 mm (the deformation just before fracture is of the order of 1 cm). The apparatus is placed inside a copper box covered with a thick foam layer to avoid both electrical and acoustical noise. Four wide-band piezoelectric microphones are placed on the side of the sample (see Fig. 1). The signal is amplified, low-pass filtered at 70 kHz, and sent to a digitizing oscilloscope and to an electronic device which measures the acoustic energy detected by the microphones. The signal captured by the oscilloscope is sent to a computer where a program automatically detects the arrival time of the AE at each microphone. Afterwards, a calculation yields the position of the source inside the sample. A fraction of the detected events is rejected, either as a result of a large uncertainty of the location, or because they are regarded as noise. The mean standard error for the calculated positions is about 6 mm, which results mainly from the uncertainty of the arrival time. The electronic device that measures the energy performs the square of the AE amplitude and then integrates it over a time window of 30 ms, which is the maximum duration of one acoustic event. The output signal is proportional to the energy of the events [11], and

Patent
22 Aug 1997
TL;DR: In this paper, an ultrasound system and a method for improving resolution and operation is presented, which applies different imaging parameters within and outside a region of interest in an ultrasound image to improve spatial and/or temporal resolution inside a region.
Abstract: An ultrasound system and method are provided for improving resolution and operation. The system applies different imaging parameters within and outside a region of interest in an ultrasound image to improve spatial and/or temporal resolution inside a region of interest. The system also increases an apparent frame rate within a region of interest in an ultrasound-image frame by generating a motion-compensated interpolated image based on measured motion. The ultrasound imaging system also performs a method for automatically adjusting ultrasound imaging parameters in at least a portion of an ultrasound image in response to transducer or image motion to improve spatial or temporal resolution. With the measured motion, the system can also alter an operating mode of an ultrasound transducer array in response to an absence of transducer motion. Further, the system corrects distortion in an acquired ultrasound image caused by transducer or image motion.

PatentDOI
TL;DR: In this paper, the authors described mathematical reconstruction procedures for producing images from transducer signals, and specific arrangements of transducers were illustrated, where the transducers are moved to collect data from multiple locations, to facilitate imaging.
Abstract: Methods and apparatus for measuring and characterizing the localized electromagnetic wave absorption properties of biologic tissues (12) in vivo, using incident electromagnetic waves to produce resultant acoustic waves (26). Multiple acoustic transducers (33) are acoustically coupled to the surface of the tissue for measuring acoustic waves produced in the tissue when the tissue is exposed to a pulse of electromagnetic radiation. The multiple transducer signals are then combined to produce an image of the absorptivity of the tissue, which image may be used for medical diagnostic purposes. In specific embodiments, the transducers are moved to collect data from multiple locations, to facilitate imaging. Specific arrangements of transducers are illustrated. Also, specific mathematical reconstruction procedures are described for producing images from transducer signals.

Patent
17 Mar 1997
TL;DR: In this article, a system for performing surgery by vibrational heating employs an ultrasonic transducer 80 for focusing a spherical ultrasound wave on a focal region, where a refraction plate 410 having a spherical surface facing the transducers and a refracting surface with refractive pyramid elements 450 facing the subject causes the ultrasound beam to impinge on a plurality of overlapping focal regions and thereby expand the focal area.
Abstract: A system for performing surgery by vibrational heating employs an ultrasonic transducer 80 for focusing a spherical ultrasound wave on a focal region. In one embodiment a refraction plate 410 having a spherical surface facing the transducer and a refracting surface with refracting pyramid elements 450 facing the subject causes the ultrasound beam to impinge on a plurality of overlapping focal regions and thereby expand the focal area of the transducer. In a second embodiment the refraction plate comprises a phased lens 600 having a constant thickness at any angular location but with its thickness varying linearly over 2π radians or multiples thereof.

Patent
24 Apr 1997
TL;DR: In this article, a perforated flexible web conformable to a patient, at least one electroacoustic transducer attached to the web, an a-c current source being operatively connected to the transducers for energizing with an electrical signal of a pre-established ultrasonic frequency to produce a first pressure wave.
Abstract: A medical system incorporates a perforated flexible web conformable to a patient, at least one electroacoustic transducer attached to the web, an a-c current source being operatively connected to the transducer for energizing the transducer with an electrical signal of a pre-established ultrasonic frequency to produce a first pressure wave. At least one acoustoelectric transducer is attached to the web, while an analyzing component is operatively connected to the acoustoelectric transducer for determining three-dimensional shapes of internal organs of the patient by analyzing signals generated by the acoustoelectric transducer in response to second pressure waves produced at internal organs of the patient in response to the first pressure wave. An image of internal organic structures derived through the ultrasonic signal analysis is displayed on a video monitor for enabling direct observation of invasive diagnostic and therapeutic operations. Instruments are inserted into the patient through apertures in the flexible ultrasonic sensor web.

Patent
05 May 1997
TL;DR: In this article, an ultrasonic imaging system capable of transmitting and receiving ultrasound over a wide frequency range, i.e., 500 KHz-300 MHz, is described. But the system requires a large number of transducer elements, each having a unique resonant frequency.
Abstract: An ultrasonic imaging system capable of transmitting and receiving ultrasound over a wide frequency range, i.e., 500 KHz-300 MHz. Ultrasound may be transmitted from a single transducer array at multiple frequencies simultaneously or sequentially via separate, acoustically isolated transducer elements, each having a unique resonant frequency. Signal-to-noise ratio may be enhanced through use of multiple piezoelectric layer transmit transducer elements and single piezoelectric layer receive transducer elements, both on a single transducer array. Aspect ratios approaching unity for transducer elements of the array may be obtained, which can be used to reduce grating lobes. Sparsely populated transducer arrays are included in the imaging system. Methods of ultrasound imaging and ultrasound therapy obtainable with the present imaging system are included in the invention.

Patent
02 Jun 1997
TL;DR: A bending plate transducer is typically a unimorph, bimorph, or other conventional vibratory transducers capable of imparting pressure waves in a direction generally normal to the plane of the transducers as mentioned in this paper.
Abstract: A catheter comprises a catheter body having a bending plate transducer disposed at or near its distal end. The bending plate transducer is typically a unimorph, bimorph, or other conventional vibratory transducer capable of imparting pressure waves in a direction generally normal to the plane of the transducer. The bending plate transducers may be disposed at a distal end of the catheter body, for example, as a cantilever beam, or may alternately be disposed within the catheter body. The catheters may further comprise lumens for drug delivery, balloons for encircling the transducer structures, or the like. The catheters are useful in a variety of lumenal therapeutic procedures, including drug delivery, stenotic disruption within blood vessel, and the like.

Patent
05 May 1997
TL;DR: An ultrasonic transducer array having a plurality of transducers, at least some of which have multiple piezoelectric and electrode layers, can be found in this paper.
Abstract: An ultrasonic transducer array having a plurality of transducer elements, at least some of which have multiple piezoelectric and electrode layers The resonant frequency of the transducer elements may range from 500 kHz to 300 MHz or more A single array may have transducer elements of different resonant frequencies, and the array may be sparsely populated Highest frequencies are typically obtained when the piezoelectric layers are made from vapor deposited PZT in accordance with a disclosed deposition process The array may have a 1-D configuration, 15-D or 2-D, configuration The array may be positioned in a probe

Patent
28 Mar 1997
TL;DR: In this paper, an apparatus for interfacing an elongated flexible object with an electrical system is described, which includes an object receiving portion and a rotation transducer coupled to the object receiving part adapted to determine the rotational motion of the elongated rigid object when the object is engaged with the receiving portion, and provide an electromechanical interface between the object and the electrical system.
Abstract: An apparatus for interfacing an elongated flexible object with an electrical system. The apparatus includes an object receiving portion and a rotation transducer coupled to the object receiving portion adapted to determine the rotational motion of the elongated flexible object when the object is engaged with the object receiving portion and to provide an electromechanical interface between the object and the electrical system. In a preferred embodiment, the rotation transducer includes an actuator and translational transducer to provide a translational electromechanical interface between the object and the electrical system.

Patent
29 Dec 1997
TL;DR: In this paper, a power meter is disclosed for determining power parameters for power lines having periodic 3-phase voltage and current signals distributed to a plurality of power equipment, where the power lines are connected to at least one transducer which generates analog signals representing the voltage and currents signals.
Abstract: A power meter is disclosed for determining power parameters for power lines having periodic 3-phase voltage and current signals distributed to a plurality of power equipment. The 3-phase voltage and current signals have a fundamental frequency. The power lines are connected to at least one transducer which generates analog signals representing the voltage and current signals. The power meter includes receiving circuitry which can be connected to the at least one transducer to receive the analog signals. An analog to digital converter receives the output signal from the receiving circuitry and converts the voltage and current signals to digital data representing the analog signals. A processor receives the digital data and includes logic for calculating the power parameters. The power meter compensates for errors caused by not sampling synchronous to the fundamental frequency of the signals.

Journal ArticleDOI
TL;DR: In this paper, a kinetic energy optimization technique (EOT) has been derived, and numerical issues are addressed and applied to real experimental data obtained from a model of an asymmetric long span bridge.

Patent
Viktors Berstis1
26 Mar 1997
TL;DR: In this article, a method and system for controlling a display of a data processing system using first and second wireless position control devices, and a control base unit, is presented, where the first wireless position controller includes an acoustical transducer for transmitting a first ultrasonic carrier signal upon which X-Y position control and/or action control signals generated by the device are imposed.
Abstract: A method and system for controlling a display of a data processing system uses first and second wireless position control devices, and a control base unit. The first wireless position control device includes an acoustical transducer for transmitting a first ultrasonic carrier signal upon which X-Y position control and/or action control signals generated by the device are imposed. A second wireless position control device includes and acoustical transducer for transmitting a second ultrasonic carrier signal upon which X-Y position control and/or other action control signals generated by the second control device are imposed. The first and second ultrasonic carrier signals have different frequencies. The control base is associated with the data processing system and includes circuitry for receiving and differentiating the first and second ultrasonic carrier signals to generate decoded display control signals. The display control signals are then used to drive the display device. Two users may thus control the display device simultaneously.

Patent
22 Aug 1997
TL;DR: In this paper, a transducer, in response to a transmit beamformer, transmits ultrasonic energy at a first frequency band into a subject, which is kept free of added ultrasound contrast agent throughout the entire imaging session.
Abstract: An ultrasound method and system are provided for producing three dimensional images. During an imaging session, a transducer, in response to a transmit beamformer, transmits ultrasonic energy at a first frequency band into a subject. The subject may be kept free of added ultrasound contrast agent throughout the entire imaging session. A receive beamformer receives ultrasonic echo information associated with the transmitted ultrasonic energy. Information signals associated with a second frequency band, such as a harmonic frequency band, are obtained from the echo information. A three-dimensional reconstruction is formed or a volume quantity is calculated in response to the information signals. The transmission of ultrasonic energy may also include energy focused along an elongated high power region or a line focus.

Patent
15 Jul 1997
TL;DR: In this article, a method of treatment by ultrasound comprises providing a first, ultrasound field intensity-to-voltage transducer sized for insertion into the vicinity of a treatment site and a second ultrasound treatment transducers.
Abstract: A method of treatment by ultrasound comprises providing a first, ultrasound field intensity-to-voltage transducer sized for insertion into the vicinity of a treatment site and a second ultrasound treatment transducer. The free field intensities created by the second transducer in response to various second transducer exciting signal levels are determined. The first transducer outputs in the free field in response to various second transducer exciting signal levels are also determined. The first transducer is inserted into the vicinity of the treatment site, and the second transducer is positioned to create an ultrasound field at the treatment site. The distance from the second transducer to the first transducer is determined. An exciting signal is applied to the second transducer. The output of the first transducer is determined. The level of the exciting signal applied to the second transducer, the determined distance and the first transducer output are employed to determine the attenuation coefficient of the tissues between the second transducer and the first transducer.

Patent
13 Mar 1997
TL;DR: In this article, a transducer receives electrical signals from a generator and transforms it into ultrasound at a preselected frequency, which is transmitted from the transducers to the application site via an acoustic transmission line.
Abstract: The present invention relates to devices and methods for enhancing the rate and efficacy of permeation of a drug into and through skin and into the circulatory system utilizing ultrasound A transducer receives electrical signals from a generator and transforms it into ultrasound at a preselected frequency The ultra sound is transmitted from the transducer to the application site via an acoustic transmission line In a closed loop embodiment a sensor, eg a temperature sensor, provides a feedback signal via a control electronic circuit to the generator

Patent
06 Jun 1997
TL;DR: In this paper, an improved controller for externally powered prosthetic limb devices or similar extension devices such as orthotic devices or a sensor probe device is described. And the improved controller operates a highly efficient, compact, reliable and low-maintenance tactile force feedback system for translating a sensed pressure force from a prosthesis contacting an object or surface into a tactile sensory feedback pressure force to the user.
Abstract: The present invention relates to improved controllers for externally powered prosthetic limb devices or similar extension devices such as orthotic devices or a sensor probe device. The improved controller operates a highly-efficient, compact, reliable and low-maintenance tactile force feedback system for translating a sensed pressure force from a prosthesis contacting an object or surface into a tactile sensory feedback pressure force to the user. The tactile force feedback system comprises at least one contact-responsive transducer which translates a sensed contact pressure from a portion of an extension device which contacts an object or surface into a corresponding electrical signal. The electrical signal is received by a microprocessor and processed into a proportional output voltage for producing a proportional torque from a motor. The motor is connected to a backdrivable planetary gearbox having a rotatable shaft connected to one end of a lever such that the gearbox output causes the lever to move in an arc segment. The opposite end of the lever has an attached tip member positioned to contact, and slightly depress, the user's skin when the shaft is forwardly rotated. The contact pressure of the tip member is, thus, applied to the user's skin with a contact pressure force proportional to the contact pressure force sensed by the contact-responsive transducer. In addition, the improved controller may permit the user to initiate self-calibration of various selected user-dependent operating parameters whenever desired and an adaptive filter for permitting user control of the rate of movement of the device such that smooth and steady control of either slow or more rapid prosthesis movement is achieved. The improved controller may also recognize multiple trigger patterns from signal input generated from either a single or from multiple control sites to effect switching between modes of operation, i.e., degrees of freedom, and/or functions.

Journal ArticleDOI
TL;DR: A new formulation for obtaining the absolute backscatter coefficient from pulse-echo measurements is presented, and the final correction is a weak function of frequency when the scattering volume is near the focal area, rather than the frequency squared dependence proposed by earlier investigators.
Abstract: A new formulation for obtaining the absolute backscatter coefficient from pulse-echo measurements is presented. Using this formulation, performing the diffraction correction and system calibration is straightforward. The diffraction correction function for the measurement of backscatter coefficient and the acoustic coupling function for a pulse-echo system are defined. Details of these functions for two very useful cases are presented: a flat disk transducer and a spherically focused transducer. Approximations of these functions are also provided. For a flat disk transducer, the final formulation appears as a modification to the established Sigelmann-Reid formulation. For a focused transducer, the final correction is a weak function of frequency when the scattering volume is near the focal area, rather than the frequency squared dependence proposed by earlier investigators.

Patent
17 Nov 1997
TL;DR: In this paper, the rotary movement of at least one wheel on a roller skate is transmitted to a receiver worn on a user's wrist by a transducer, which produces electrical pulses corresponding to the angular velocity of the wheel.
Abstract: An in-line roller skate includes a transducer portion capable of sensing the rotary movement of at least one wheel on the roller skate and transmitting information concerning the same to a receiver worn on a user's wrist. In the preferred embodiment, the transducer portion includes a magnet attached to one of the plurality of wheels and a sensor positioned in a shoe portion to detect the magnet and produce electrical pulses containing information corresponding to the angular velocity of the wheel. The transducer portion also includes a micro-controller, a transmitter and an antenna. The micro-controller creates a digital data stream containing information corresponding to the angular velocity of the wheel, which is then modulated onto a carrier wave produced by the transmitter. The transmitter transmits the coded signals to the receiver. The receiver demodulates the carrier wave, reproducing the digital data stream. A microprocessor processes the modulated signals and drives the display to produce a real time visual representation of selected portions of information contained in the digital data stream, including speed and distance travelled by the skate.