Ferroelectrics are essential components in a wide range of applications, including ultrasonic transducers, sensors, and actuators. In the single crystal form, relaxor-PbTiO3 (PT) piezoelectric materials have been extensively studied due to their ultrahigh piezoelectric and electromechanical properties. In this article, a perspective and future development of relaxor-PT crystals are given. Initially, various techniques for the growth of relaxor-PT crystals are reviewed, with crystals up to 100 mm in diameter and 200 mm in length being readily achievable using the Bridgman technique. Second, the characterizations of dielectric and electromechanical properties are surveyed. Boundary conditions, including temperature, electric field, and stress, are discussed in relation to device limitations. Third, the physical origins of the high piezoelectric properties and unique loss characteristics in relaxor-PT crystals are discussed with respect to their crystal structure, phase, engineered domain configuration, macr...

/pdf/high-performance-ferroelectric-relaxor-pbtio3-single-3cp5am04w0.pdf

High performance ferroelectric relaxor-PbTiO3 single crystals: Status and perspective

Advantages and Challenges of Relaxor-PbTiO3 Ferroelectric Crystals for Electroacoustic Transducers- A Review.

Systems including an implantable receiver-stimulator and an implantable controller-transmitter are used for leadless electrical stimulation of body tissues. Cardiac pacing and arrhythmia control is accomplished with one or more implantable receiver-stimulators and an external or implantable controller-transmitter. Systems are implanted by testing external or implantable devices at different tissue sites, observing physiologic and device responses, and selecting sites with preferred performance for implanting the systems. In these systems, a controller-transmitter is activated at a remote tissue location to transmit/deliver acoustic energy through the body to a receiver-stimulator at a target tissue location. The receiver-stimulator converts the acoustic energy to electrical energy for electrical stimulation of the body tissue. The tissue locations(s) can be optimized by moving either or both of the controller-transmitter and the receiver-stimulator to determine the best patient and device responses.

Leadless tissue stimulation systems and methods

Probing Systems in Dimensional Metrology

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.

Optimizing energy transmission in a leadless tissue stimulation system

Nondestructive measurement of microscale features remains a challenging metrology problem. For example, to assess a high aspect ratio small hole it is currently common to cut a cross section and measure the features of interest using an atomic force microscope, scanning probe microscope, or scanning electron microscope. Typically, these metrology tools may be suitable for surface finish measurement but often lack the capability for dimensional metrology. The aim of this article is to discuss the development of a high aspect-ratio microscale probe for measurement of microscale features. A 700:1 high aspect ratio probe shank is fabricated with a 7μm diameter, and attached at one end to an oscillator. The oscillator produces a standing wave in the oscillating probe shank as opposed to conventional probes that use a microscale sphere on the end of a comparatively rigid shank. As a result of the standing wave formed in steady state vibration, the free end of the shank generates an amplitude of oscillation grea...

Development of a virtual probe tip with an application to high aspect ratio microscale features

A closed loop motion control system employing at least one relaxor actuator which controls the position of a moving member having mass by controlling an electric field applied to the relaxor actuator. The actuator comprises a body of relaxor material dimensionally variable under the influence of the electric field applied in the form of a voltage to electrodes on at least two surfaces of the actuator. The voltage is applied in response to a feedback signal produced by at least one feedback sensor, which may be a displacement sensor or some other type of sensor. Thus, by constantly monitoring the displacement or other variable of the actuator device, the position of the moving member may be precisely controlled.

Closed loop control systems employing relaxor ferroelectric actuators

Design and performance of a dual drive system for tip-tilt angular control of a 300 mm diameter mirror

A compact, fiber-coupled, six degree-of-freedom measurement system which enables fast, accurate calibration, and error mapping of precision linear stages is presented. The novel design has the advantages of simplicity, compactness, and relatively low cost. This proposed sensor can simultaneously measure displacement, two straightness errors, and changes in pitch, yaw, and roll using a single optical beam traveling between the measurement system and a small target. The optical configuration of the system and the working principle for all degrees-of-freedom are presented along with the influence and compensation of crosstalk motions in roll and straightness measurements. Several comparison experiments are conducted to investigate the feasibility and performance of the proposed system in each degree-of-freedom independently. Comparison experiments to a commercial interferometer demonstrate error standard deviations of 0.33 μm in straightness, 0.14 μrad in pitch, 0.44 μradin yaw, and 45.8 μrad in roll.

Development of a compact, fiber-coupled, six degree-of-freedom measurement system for precision linear stage metrology

An apparatus for profiling the surface of a workpiece, including a probe adapted to make contact with the surface of a workpiece, a sensor for determining or deriving the force between the probe and the workpiece surface, an actuator that adjusts the position of the probe along an axis, which is generally perpendicular to the surface of the workpiece, in order to maintain a constant force between the probe and the surface, and a closed control loop, including a controller that controls the operation of the actuator based on information from the sensor.

Shane C. Woody

Papers

Development of a virtual probe tip with an application to high aspect ratio microscale features

Closed loop control systems employing relaxor ferroelectric actuators

Design and performance of a dual drive system for tip-tilt angular control of a 300 mm diameter mirror

Development of a compact, fiber-coupled, six degree-of-freedom measurement system for precision linear stage metrology

Method and apparatus using a closed loop controlled actuator for surface profilometry