Showing papers on "Transducer published in 2008"

Transducers and Arrays for Underwater Sound

Abstract: The subject of this book is the theory, development and design of electroacoustic transducers for underwater applications. It is more comprehensive than any existing book in this field. It includes the basics of the six major types of electroacoustic transducers and shows why piezoelectric ceramic transducers are the most suitable for underwater sound. It presents the basic acoustic concepts and models needed in transducer and transducer array development, and discusses most currently used transducer designs. It analyzes nonlinear effects and describes methods of transducer evaluation and measurement. The extensive Appendix and numerous diagrams provide an up to date source for use by students and practicing engineers and scientists. A complete set of exercises and solutions from the book are currently available on the Springer website.

Piezoelectric and Acoustic Materials for Transducer Applications

Abstract: Fundamentals of Piezoelectricity- Thermodynamics of Ferroelectricity- Piezoelectricity and Crystal Symmetry- Crystal Chemistry of Piezoelectric Materials- Piezoelectric and Acoustic Materials for Transducer Technology- Lead-Based Piezoelectric Materials- KNN-Based Piezoelectric Ceramics- Bismuth-based Piezoelectric Ceramics- Electropolymers for Mechatronics and Artificial Muscles- Low-Attenuation Acoustic Silicone Lens for Medical Ultrasonic Array Probes- Carbon-Fiber Composite Materials for Medical Transducers- Transducer Design and Principles- Piezoelectric Transducer Design for Medical Diagnosis and NDE- Piezoelectric Transducer Designs for Sonar Applications- Finite Element Analysis of Piezoelectric Transducers- Piezoelectric Transducer Fabrication Methods- Piezoelectric Fiber Composite Fabrication- Composition Gradient Actuators- Robocasting of Three-Dimensional Piezoelectric Structures- Micropositioning- Piezoelectric Actuator Designs- Piezoelectric Energy Harvesting using Bulk Transducers- Piezocomposite Ultrasonic Transducers for High-Frequency Wire Bonding of Semiconductor Packages- Piezoelectric MEMS: Materials and Devices- High-Frequency Ultrasonic Transducers and Arrays- Micromachined Ultrasonic Transducers

Temperature controlled ultrasonic surgical instruments

Abstract: A surgical instrument includes a transducer configured to produce vibrations at a predetermined frequency. An ultrasonic blade extends along a longitudinal axis and is coupled to the transducer. A controller receives a feedback signal from the ultrasonic blade. A lumen is adapted to couple to a pump. The lumen conducts a fluid therethrough based on the feedback signal.

Optimizing energy transmission in a leadless tissue stimulation system

Abstract: Method and systems for optimizing acoustic energy transmission in implantable devices are disclosed. Transducer elements transmit acoustic locator signals towards a receiver assembly, and the receiver responds with a location signal. The location signal can reveal information related to the location of the receiver and the efficiency of the transmitted acoustic beam received by the receiver. This information enables the transmitter to target the receiver and optimize the acoustic energy transfer between the transmitter and the receiver. The energy can be used for therapeutic purposes, for example, stimulating tissue or for diagnostic purposes.

Integration of 2D CMUT arrays with front-end electronics for volumetric ultrasound imaging

Abstract: For three-dimensional (3D) ultrasound imaging, connecting elements of a two-dimensional (2D) transducer array to the imaging system's front-end electronics is a challenge because of the large number of array elements and the small element size. To compactly connect the transducer array with electronics, we flip-chip bond a 2D 16 times 16-element capacitive micromachined ultrasonic transducer (CMUT) array to a custom-designed integrated circuit (IC). Through-wafer interconnects are used to connect the CMUT elements on the top side of the array with flip-chip bond pads on the back side. The IC provides a 25-V pulser and a transimpedance preamplifier to each element of the array. For each of three characterized devices, the element yield is excellent (99 to 100% of the elements are functional). Center frequencies range from 2.6 MHz to 5.1 MHz. For pulse-echo operation, the average -6-dB fractional bandwidth is as high as 125%. Transmit pressures normalized to the face of the transducer are as high as 339 kPa and input-referred receiver noise is typically 1.2 to 2.1 rnPa/ radicHz. The flip-chip bonded devices were used to acquire 3D synthetic aperture images of a wire-target phantom. Combining the transducer array and IC, as shown in this paper, allows for better utilization of large arrays, improves receive sensitivity, and may lead to new imaging techniques that depend on transducer arrays that are closely coupled to IC electronics.

Non-contact Method for Producing Tactile Sensation Using Airborne Ultrasound

Abstract: This paper describes a new tactile device which produces stress fields in 3D space. Combined with 3D stereoscopic displays, this device is expected to provide high-fidelity tactile feedback for the interaction with 3D visual objects. The principle is based on a non-linear phenomenon of ultrasound, acoustic radiation pressure. We fabricated a prototype device to confirm the feasibility as a tactile display. The prototype consists of 91 airborne ultrasound transducers packed in the hexagonal arrangement, a 12 channel driving circuit, and a PC. The transducers which were in the same distance from the center of the transducer array were connected to form a 12 channel annular array. The measured total output force within the focal region was 0.8 gf. The spatial resolution was 20 mm. The prototype could produce sufficient vibrations up to 1 kHz.

Devices and methods for decreasing residual chucking forces

Abstract: Devices and methods are disclosed for holding a reticle or analogous object, particularly a planar object. An exemplary reticle-holding device includes a reticle chuck having a reticle-holding surface on which a reticle is placed to hold the reticle. The device includes at least one ultrasonic transducer (as an exemplary vibration-inducing device) sonically coupled to the reticle to excite, whenever the ultrasonic transducer is being energized, a vibrational mode in the reticle or reticle chuck, or both. The vibration mode is sufficient to reduce an adhesion force holding the reticle to the reticle-holding surface. Sonic coupling can be by direct contact with the transducer or across a gap.

Importance of transducer position in the assessment of apical rotation by speckle tracking echocardiography.

Abstract: Background Speckle tracking echocardiography is increasingly used to quantify left ventricular (LV) twist. However, one of the limitations of the assessment of LV twist by speckle tracking echocardiography is the crucial dependence on correct acquisition of a LV apical short-axis. This study sought to assess the influence of transducer position on LV apical rotation measurements. Methods The study population consisted of 58 consecutive healthy volunteers (mean age 38 ± 13 years, 25 men). To obtain parasternal short-axis images at the LV apical level, the following protocol was used. From the standard parasternal position (LV and aorta most inline, with the mitral valve tips in the middle of the sector) an as-circular-as-possible short-axis image of the LV apex, just proximal to the level with end-systolic LV luminal obliteration, was obtained by angulation of the transducer (position 1). From this position, the position of the transducer was changed to one (position 2) and two (position 3) intercostal spaces more caudal with subsequent similar transducer adaptations. Results In 8 volunteers (14%) parasternal image quality was insufficient for speckle tracking echocardiography. In 13 volunteers (22%) the LV apical short-axis could only be obtained from one transducer position. In the remaining volunteers with two (n = 27) or three (n = 10) available transducer positions, a more caudal transducer position was associated with increased measured LV apical rotation. Mean measured LV apical rotation was 5.2 ± 1.8 degrees at position 1, 7.3 ± 2.6 degrees at position 2 ( P P P Conclusion A more caudal transducer position is associated with increased measured LV apical rotation.

Method for providing and utilizing an electronic lapping guide in a magnetic recording transducer

Abstract: A method for providing an electronic lapping guide (ELG) for a structure in a magnetic transducer are described. The structure has a front edge and a back edge. The ELG includes a stripe having a top edge and a bottom edge. The method includes calibrating a sheet resistance of the stripe and calibrating an offset of the top edge of the stripe from the back edge of the structure. The method further includes terminating the lapping based at least on the sheet resistance and offset of the ELG.

Electroactive polymer transducers for sensory feedback applications

Abstract: PROBLEM TO BE SOLVED: To further improve haptic feedback capabilities, particularly in the context of user productivity and efficiency in data entry, through further improvement in characteristics and quality of haptic sensation communicated to a user.SOLUTION: Electroactive polymer transducers for sensory feedback applications are disclosed. A user interface device having sensory feedback includes; a user contact surface; an electroactive polymer transducer having an output member coupled to the contact surface; a sensor for sensing mechanical force on the user contact surface and providing an activation signal to the transducer (activation of the transducer moves at least a portion of the user contact surface); and a sealing material adapted to substantially hermetically seal the transducer.

Method and system for providing a magnetic head using a composite magnetic material in the recording transducer

Abstract: A method and system for providing a magnetic transducer for recording to media is described. The method and system include providing a first pole, a main pole, at least one coil and at least one auxiliary pole. The main pole is for providing a magnetic field for recording to the media. The coil(s) are for energizing the main pole. The auxiliary pole is magnetically coupled with the main pole. The shield(s) are for magnetically isolating a portion of the magnetic transducer. At least one of the first pole, the auxiliary pole, and the at least one shield includes a composite magnetic material including a plurality of ferromagnetic grains in an insulating matrix.

Multiple end effectors ultrasonic surgical instruments

Abstract: A surgical instrument includes a transducer configured to produce vibrations along a longitudinal axis at a predetermined frequency. The transducer includes a first end and a second end. A first resonator portion includes a first end coupled to the first end of the transducer. The first resonator includes a second end adapted to receive a first ultrasonic transmission waveguide. A second resonator portion includes a first end coupled to the second end of the transducer. The second resonator includes a second end adapted to receive a second ultrasonic transmission waveguide.

Micro-actuator enabling single direction motion of a magnetic disk drive head

Abstract: A magnetic recording device comprises a slider body having a slider interface surface and a magnetic transducer having a lower surface coplanar with an air bearing surface of the magnetic recording device The magnetic transducer has a transducer interface surface perpendicular to the air bearing surface The magnetic recording device further comprises a piezoelectric actuator operably connecting the slider interface surface and the transducer interface surface The piezoelectric actuator is configured to translate the magnetic transducer with respect to the slider body in a direction substantially parallel to the slider and transducer interface surfaces The piezoelectric actuator comprises a plurality of elongate flexures disposed in parallel planes within a body of the piezoelectric actuator

Characterization of Mn-modified Pb(Mg1∕3Nb2∕3)O3–PbZrO3–PbTiO3 single crystals for high power broad bandwidth transducers

Abstract: The effect of MnO2 addition on the dielectric and piezoelectric properties of 0.4Pb(Mg1∕3Nb2∕3)O3–0.25PbZrO3–0.35PbTiO3 single crystals was investigated. Analogous to acceptor doping in “hard” Pb(Zr,Ti)O3 based polycrystalline materials, the Mn doped crystals exhibited enhanced mechanical Q (∼1050) with low dielectric loss (∼0.2%), while maintaining ultrahigh electromechanical coupling k33>90%, inherent in domain engineered single crystals. The effect of acceptor doping was also evident in the build-up of an internal bias (Ei∼1.6kV∕cm), shown by a horizontal offset in the polarization-field behavior. Together with the relatively high usage temperature (TR-T∼140°C), the Mn doped crystals are promising candidates for high power and broad bandwidth transducers.

Patient wye with flow transducer

Abstract: A patient wye for use in connection with a ventilator having one or more integrated transducers is provided. A transducer is integrated into the patient wye by locating the transducer within a branch of the patient wye. A transducer can be located between the center point of the wye and the port of the branch with which it is associated. More particularly, the transducer can be located so that it is on a side of a wall defining the branch in which it is placed that is opposite a connection surface for attaching tubing associated with a corresponding limb of the ventilator to the patient wye. Accordingly, flow or other transducers can be added to a patient circuit without necessarily increasing the volume of the patient circuit.

Device And Method for Non-Invasive Neuromodulation

Abstract: One embodiment involves modifying neural transmission patterns between neural structures and/or neural regions in a noninvasive manner. In a related exemplary method, sound waves are directed toward a first targeted neural structure and characteristics of the sound waves are controlled at the first target neural structure with respect to characteristics of sound waves at the second target neural structure. In response, neural transmission patterns modified to produce the intended effect (e.g., long-term potentiation and long-term depression of the neural transmission patterns). In a related embodiment, a transducer produces the sound for stimulating the first neural structure and the second neural structure, and an electronically-based control circuit is used to control characteristics of the sound waves as described above to modify the neural transmission patterns between the first and second neural structures.

Measuring transducer movement methods and systems for multi-dimensional ultrasound imaging

Abstract: Methods and systems for measuring transducer movement are provided. For example, free-hand scanning for three-dimensional imaging is provided. An optical sensor within the transducer measures motion along the skin surface similar to measuring movement of a personal computer mouse with an optical sensor. Alternatively or additionally, the transducer is tilted at an angle other than perpendicular to the skin surface generally towards or away from the direction in which the transducer is translated. The transducer is then translated while maintaining the angle. Motion to or from the transducer is measured, and a component of the motion measured while the transducer is maintained at an angle is parallel to the direction of translation. The component of motion is angle corrected and used to determine a distance of travel.

Improved surgical instruments

Abstract: A surgical device. The surgical device may comprise a transducer, an end effector, a generator and a control circuit. The transducer may be configured to provide vibrations. The end effector may be coupled to the transducer and may extend from the transducer along the longitudinal axis. The generator may provide an electrical signal to the transducer. Also, the control circuit may modify a current amplitude of the electrical signal in response to a change in a vibration frequency of the end effector. Accordingly to various embodiments, the control circuit may detect a first contribution to a vibration frequency of the end effector, the first contribution originating from tissue in contact with the end effector. Also, according to various embodiments, the control circuit may indicate a change in a vibration frequency of the end effector.

System and method for generating energy from activation of an input device in an electronic device

Abstract: In this disclosure, a description of a system for providing feedback signals relating to input signals provided to an electronic device is provided. The system comprises: an input device; a transducer associated with the input device; and a feedback module to generate a feedback signal indicating activation of the input device on the electronic device based on signals from the input device. The input device may be a touchpad; the transducer may be a piezoelectric element; and the feedback module may cause the transducer to vibrate upon receiving an activation signal relating to activation of the input device. The feedback module may provide a voltage generated by the transducer during the activation of the input device to an energy storage circuit.

Time-Domain Spectral Element Method for Built-In Piezoelectric-Actuator-Induced Lamb Wave Propagation Analysis

Abstract: An investigation was performed to develop a computational model based on a spectral element method to simulate piezoelectric-actuator-induced acousto-ultrasonic wave propagation in a metallic structure. The model solves the coupled electromechanical field equations simultaneously in both three-dimensional and two-dimensional plane strain conditions, and so it can accept any arbitrary waveform of electrical voltage as input to any piezoelectric transducer and produce piezoelectric sensor output in voltage as a result of the excitation generated by the transducer. Basically, the model inputs electrical voltage to actuators and outputs electrical signals of sensors. To visualize the transient dynamic wave motions in the structure generated by the transducer, the code is integrated with commercial pre/postprocessing software to provide graphical outputs of the dynamic deformations of the structure. The code was verified by comparison with experimental results. Performance of the model was examined in terms of solution convergence compared with the finite element method.

System and method for three-dimensional ultrasound imaging

Abstract: Under one aspect, an ultrasound system for producing a representation of an object includes: a concave transducer array configured to transmit ultrasonic pulses into the object and to receive ultrasonic pulses from the object, the ultrasonic pulses from the object containing structural information about the object, each transducer in the array generating an output signal representative of a portion of the structural information about the object; a multi-focal lens structure for focusing the transmitted ultrasonic pulses; a multiplexing structure in operable communication with the concave transducer array and including logic for coupling the output signals from at least one pair of transducers in the concave transducer array; and a beamformer in operable communication with the multiplexing structure and including logic for constructing a representation of structural information about the object based on the coupled output signals from the multiplexing structure

Piezoelectric energy harvester

Abstract: A mechanism for capturing mechanical energy and converting it to electrical energy for use continually charging or providing emergency power to mobile, battery-powered devices comprises a plurality of elongated piezoelectric elements mounted at one or support points to one or more support structures. The plurality of piezoelectric elements are preferably structured and arranged so that at least each three-dimensional coordinate axis has at least one element with a dominant mode of deflection in a plane normal to the axis, in order to permit harvesting energy from forces applied in any direction without regard to the orientation of the energy harvesting mechanism to the source of forces. This results in improved coupling of the transducer with the random movements or vibrations that may not confined to any particular plane or in a plane that is not necessarily aligned with the plane in which a piezoelectric element is designed to bend, thus improving the efficiency of energy capture.

MEMS device and process

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalization of the air volumes above and below the membrane.

System and Method for Alignment of Instrumentation in Image-Guided Intervention

Abstract: The invention provides systems and methods for aligning or guiding instruments during image-guided interventions. A volumetric medical scan (image data) of a patient may first be registered to patient space data regarding the patient obtained using a tracking device. An ultrasound simulator fitted with position indicating elements whose location is tracked by the tracking device is introduced to the surface of the anatomy of the patient and used to determine an imaginary ultrasound scan plane for the ultrasound simulator. This scan plane is used to reformat the image data so that the image data can be displayed to a user in a manner analogous to a handheld ultrasound transducer by re-slicing the image data according to the location and orientation of the ultrasound simulator. The location of an instrument fitted with position indicating elements tracked by the tracking device may be projected onto the re-sliced scan data.

Light Weight Wireless Ultrasound Probe

Abstract: A wireless ultrasound probe has a probe case enclosing a transducer array stack, a microbeamformer coupled to the transducer array, an acquisition module, an ultra wideband transceiver, a power circuit, and a rechargeable battery with a total weight of 300 grams or less Preferably the total weight of these components does not exceed 150 grams, and most preferably the total weight of these components does not exceed 130 grams The transceiver wirelessly transmits echo information signals to an ultrasound system host where the signals may undergo additional ultrasound signal processing such as further beamforming, image processing and display The battery is preferably a rechargeable battery and the antenna for the transceiver is located at the end of the probe opposite the transducer stack

Imaging algorithms for locating damage via in situ ultrasonic sensors

Abstract: Permanently mounted ultrasonic sensors arranged as a spatially distributed array are being considered for in situ monitoring of the integrity of structural components. Here we consider two imaging algorithms for locating damage based upon changes in received signals. All transducer pairs in the array are considered, with each transducer acting in turn as a transmitter and the remaining transducers as receivers. The first imaging algorithm is based upon spatially distributing the differenced signals between each transducer pair as per expected arrival times for discrete scatterers. The resulting images, which consist of concentric ellipses, are summed over all pairs to form the final image. The second algorithm is based upon the cross correlation between waveforms originating from the same transmitter and received by two different transducers. The cross correlation waveforms, which capture the time difference of arrival between two pairs, are similarly distributed and summed to form the final image via a hyperbolic rather than an elliptical relationship. Results are shown for artificial damage in an aluminum plate.

Wedge transducer design for two-dimensional ultrasonic manipulation in a microfluidic chip

Abstract: We analyze and optimize the design of wedge transducers used for the excitation of resonances in the channel of a microfluidic chip in order to efficiently manipulate particles or cells in more t ...

Fabrication of Flexible Transducer Arrays With Through-Wafer Electrical Interconnects Based on Trench Refilling With PDMS

Abstract: Flexible transducer arrays are desired to wrap around catheter tips for side-looking intravascular ultrasound imaging. We present a technique for constructing flexible capacitive micromachined ultrasonic transducer (CMUT) arrays by forming polymer-filled deep trenches in a silicon substrate. First, we etch deep trenches between the bottom electrodes of CMUT elements on a prime silicon wafer using deep reactive ion etching. Second, we fusion-bond a silicon-on-insulator (SOI) wafer to the prime silicon wafer. Once the silicon handle and buried oxide layers are removed from the back side of the SOI wafer, the remaining thin silicon device layer acts as a movable membrane and top electrode. Third, we fill the deep trenches with polydimethylsiloxane, and thin the wafer down from the back side. The 16 by 16 flexible 2-D arrays presented in this paper have a trench width that varies between 6 and 20 ; the trench depth is 150 ; the membrane thickness is 1.83 ; and the final substrate thickness is 150 . We demonstrate the flexibility of the substrate by wrapping it around a needle tip with a radius of 450 (less than catheter size of 3 French). Measurements in air validate the functionality of the arrays. The 250- by 250- transducer elements have a capacitance of 2.29 to 2.67 pF, and a resonant frequency of 5.0 to 4.3 MHz, for dc bias voltages ranging from 70 to 100 V.

Three-dimensional photoacoustic imager and methods for calibrating an imager

Abstract: A photoacoustic imaging apparatus is provided for medical or other imaging applications and also a method for calibrating this apparatus. The apparatus employs a sparse array of transducer elements and a reconstruction algorithm. Spatial calibration maps of the sparse array are used to optimize the reconstruction algorithm. The apparatus includes a laser producing a pulsed laser beam to illuminate a subject for imaging and generate photoacoustic waves. The transducers are fixedly mounted on a holder so as to form the sparse array. A photoacoustic (PA) waves are received by each transducer. The resultant analog signals from each transducer are amplified, filtered, and converted to digital signals in parallel by a data acquisition system which is operatively connected to a computer. The computer receives the digital signals and processes the digital signals by the algorithm based on iterative forward projection and back-projection in order to provide the image.