Measurement of LiNbO₃ Rectangular Plate Under Large Vibration Velocity of the First Longitudinal and Second Flexural Modes

Abstract

We have studied a miniature ultrasonic motor using a piezoelectric single-crystal LiNbO3. The crystal vibrator retains superior characteristics even when the vibrational velocity is large. On the other hand, a vibrator using a resonance mode shows no signs of an operating limit and fractures itself when the vibrational velocity exceeds the limit. Such behavior causes a problem in controlling the achievement of a large output power from the motor. Therefore we must investigate the vibrational characteristics at a high vibration level and at the fracture limit. In this study, the samples were examined for their vibrational characteristics at a high driving level and at the fracture limit. First, the characteristics of the resonance vibration of the first longitudinal and second flexural modes in an X128°-rotated Y-cut rectangular plate were measured. Second, to evaluate the difference caused by the cut angle of the X-rotation, the characteristics for the first longitudinal mode of X128°-, X135°-, X140°- and X155°-rotated Y-plates were measured; additionally, for each rotation-angle plate, we measured the characteristics of the rectangular plates whose longer side was directed along the x- or z′-axis. In this paper, we describe the experimental results for the high-power characteristics and the fracture limits.

A Shear-Mode Ultrasonic Motor Using Potassium Sodium Niobate-Based Ceramics with High Mechanical Quality Factor

“…For the driving elements of ultrasonic motors, piezoelectric ceramics should possess a high mechanical quality factor Q m as well as a high piezoelectric constant d and electromechanical coupling factor k. However, lead-free piezoelectric ceramics that meet these demands have not yet been developed. To date, ultrasonic motors driven with lead-free materials were only reported by Tamura et al 4) and Doshida et al 5) The material employed in the former study was LiNbO 3 single crystal, which will increase the cost; the latter one employed multilayer-type piezoelectric elements as well as a displacement-enhancing mechanism to obtain sufficient displacement for the motor operation, obviously increasing the cost and size of the motors, which may decrease the advantage of ultrasonic motors. Therefore, ultrasonic motors made of a single plate of lead-free ceramics are desired at present.…”

Introduction of measurement techniques in ultrasonic electronics: Basic principles and recent trends

“…Filters=duplexers [208][209][210][211][212][213][214][215][216][217][218] Resonators [219][220][221][222][223] SAW sensors 20,209,[211][212][213]216,217,219, Ultrasonic transducers [262][263][264][265][266][267][268][269][270][271] Functional modules [272][273][274][275] Piezoelectric transformers 276) Nonlinear devices 260,277,278) Acoustic sensors (physical, chemical, bio, etc. )…”

“…By employing this feature, SAW devices are used as sensors, which are called SAW sensors. 20,209,[211][212][213]216,217,219, Since piezoelectric devices are essentially electromechanical transducers, they are very often used as ultrasonic transducers [262][263][264][265][266][267][268][269][270][271] and in functional modules [272][273][274][275] as sensors and actuators. Piezoelectric transducers generally have reversibility in their operation.…”

A high-temperature piezoelectric linear actuator operating in two orthogonal first bending modes

“…A typical design for a miniature piezoelectric actuator is to use a double-mode piezoelectric rectangular plate actuator in which the first longitudinal (L 1 ) and the second bending (B 2 ) vibration modes are excited synchronously. [15][16][17][18] The resultant motion of the two vibration modes is a desired elliptic motion, which is then used to drive a contacted slider into linear motion via friction force. In order to keep piezoelectric motor working stable above 150 C, piezoelectric materials without serious depolarization and capable of generating vibrations at such harsh circumstance are needed.…”