Views:1 Author:Site Editor Publish Time: 2019-03-31 Origin:Site
In the past 20 years, piezoelectric ceramics transducers have developed rapidly at home and abroad. Due to its simple production, low cost and good stability, it has been widely used in the fields of electronics, light, heat and acoustics, and has a broad development. prospect. Ultrasonic transducers made of piezoelectric ceramics can produce ultrasonic waves with good directivity. They are ideal for measuring parameters such as speed and distance, and can work stably and reliably even under harsh environmental conditions.
Piezoelectric ultrasonic transducers are made using the piezoelectric effect of piezoelectric materials. The polarized piezoelectric material undergoes mechanical deformation under the action of an applied electric field. This is called the inverse piezoelectric effect. Conversely, the mechanical deformation of the piezoelectric material also generates a voltage, which is called the positive piezoelectric effect. By using the inverse piezoelectric effect, the high-frequency voltage can be converted into high-frequency mechanical vibration to generate ultrasonic waves; the positive piezoelectric effect can also be used to convert the received ultrasonic vibration into an electrical signal. This is how the ultrasonic transducer works. A distance measuring transducer can be regarded as a four-terminal network J having an electrical end and a mechanical end. The force F and the velocity of the mechanical end, the voltage and current of the electrical terminal are linear with each other, wherein z is a constant voltage (or The electrical impedance of an electrical short circuit; the electrical conductance at a constant speed; A is called the force factor, and these parameters are generally a function of frequency.
Selection of piezoelectric materials
Piezoelectric materials for making ultrasonic sensor transducer include piezoelectric single crystals, polycrystalline piezoelectric ceramics, piezoelectric high polymers, and piezoelectric composite materials. Among them, lead zirconate titanate piezoelectric ceramics have the advantages of high mechanical strength, temperature and humidity resistance, low cost and good electromechanical coupling effect, and have been widely used in ultrasonic transducers. The ultrasonic transducer in the ultrasonic range finder uses the lead zirconate titanate piezoelectric ceramic as the vibrator material.