Application of Piezoelectric Ceramics

Piezoelectric ceramics refer to ferroelectric ceramics made of mixed oxides (zirconia, lead oxide, titanium oxide, etc.) after high-temperature sintering and solid-phase reaction, and through DC high-voltage polarization treatment to make it have piezoelectric effect Collectively. It is a functional ceramic material that can convert mechanical energy and electrical energy. Due to its good mechanical properties and stable piezoelectric properties, piezoelectric ceramics are used as an important force, heat, electricity, and light-sensitive functional material. And it has been widely used in sensors, ultrasonic transducers, micro-displacers, and other electronic components.

 

Since the birth of the first ceramic piezoelectric material barium titanate in 1942, as an application product of piezoelectric ceramics, it has spread all aspects of people's lives. As the link of electromechanical coupling,  the application of piezoelectric materials can be roughly divided into two aspects: the application of piezoelectric ceramic frequency control devices represented by piezoelectric resonators and the application of quasi-static that convert mechanical energy and electrical energy.

 

Piezoelectric vibrator and piezoelectric ceramic frequency control device

 

The polarized piezoelectric ceramic, that is, the piezoelectric vibrator, has a natural vibration frequency determined by its size. It uses the natural frequency of the piezoelectric vibrator and the piezoelectric effect to obtain stable electrical oscillation. When the frequency of the applied voltage is the same as the natural vibration frequency of the piezoelectric vibrator, resonance will be caused, and the amplitude will be greatly increased. In this process, the alternating electric field generates strain through the inverse piezoelectric effect, and the strain generates a current through the positive piezoelectric effect. This achieves the maximum mutual conversion of electrical energy and mechanical energy. Using the characteristics of piezoelectric vibrators, various filters, resonators, and other devices can be manufactured.

 

These devices have the characteristics of low cost, small size, non-moisture absorption, long life, and good frequency stability. In addition, their equivalent quality factor is higher than that of the LC filter, the applicable frequency range is wide, and the accuracy is high. Especially used in multi-channel communication, amplitude modulation receiving, and various radio communication and measuring instruments can improve the anti-interference ability. So it has replaced a considerable part of electromagnetic oscillators and filters, and this trend is still developing.

 

Piezoelectric transformer

 

Piezoelectric transformers are made by using the characteristics of the mutual conversion of electrical energy and mechanical energy of the piezoelectric effect. It is composed of two parts, an input end, and an output end, and the polarization directions are perpendicular to each other. The input end is polarized in the thickness direction, and the alternating voltage is applied for longitudinal vibration. Due to the inverse piezoelectric effect, there will be a high voltage output at the output.

 

The piezoelectric ceramic transformer is a new type of solid-state electronic device. Compared with the traditional electromagnetic transformer, it has advantages of a simple structure, small size, lightweight, large transformation ratio, good stability, no electromagnetic interference and noise, high efficiency, high energy density, high safety, no winding, no combustion, no magnetic leakage phenomenon and electromagnetic radiation pollution.

 

According to the working mode of the piezoelectric ceramic transformer, it can be divided into the following categories: Rosen type piezoelectric ceramic transformer, thickness vibration mode piezoelectric ceramic transformer, radial vibration mode piezoelectric ceramic transformer, etc.

 

In recent years, some piezoelectric transformers with better performance have appeared, such as the third-order vibration mode Rosen-type piezoelectric ceramic transformer with two input terminals and the high-power multilayer piezoelectric ceramic transformer. At present, piezoelectric ceramic transformers are mainly used in AC-DC, DC-DC, and other power devices and high-voltage generating devices, such as cold cathode tubes, neon tubes, laser tubes and small X-ray tubes, high-voltage electrostatic spraying, high-voltage electrostatic flocking, and radar display tube drive, etc.

 

Piezoelectric transducer

 

The piezoelectric transducer uses the piezoelectric effect and the inverse piezoelectric effect of piezoelectric ceramics to realize the mutual conversion of electric energy and sound energy. It is an underwater acoustic device that transmits and receives ultrasonic waves underwater. Under the action of sound waves, the piezoelectric transducer in the water induces electric charges at both ends of the transducer, which is the sound wave receiver. If an alternating electric field is applied to a piezoelectric ceramic sheet, the ceramic sheet will sometimes become thinner and sometimes thicker, and at the same time, it will vibrate and emit sound waves. This is the ultrasonic transmitter.

 

Piezoelectric transducers are also widely used in the industry for underwater navigation, ocean exploration, precision measurement, ultrasonic cleaning, solid detection, and medical imaging, ultrasonic diagnosis, and ultrasonic disease treatment. Another application field of today's piezoelectric ultrasonic transducers is telemetry and remote control systems. The specific application examples mainly include piezoelectric ceramic buzzers, piezoelectric igniters, and ultrasonic microscopes.

 

Piezoelectric ultrasonic motor

 

The piezoelectric ultrasonic motor is a new type of micromotor that uses the inverse piezoelectric effect of piezoelectric ceramics to generate ultrasonic vibration, amplifies the micro deformation of the material through resonance, and is driven by the friction between the vibrating part and the moving part, without the usual electromagnetic coil.

 

Compared with traditional electromagnetic motors, it has low cost, simple structure, small size, high power density, good low-speed performance (can achieve low-speed operation without deceleration mechanism), torque and braking torque, fast response, control high precision, no magnetic field and electric field, no electromagnetic interference and electromagnetic noise.

 

Due to its own characteristics and performance advantages, piezoelectric ultrasonic motors are widely used in precision instruments, aerospace, automatic control, office automation, micromechanical systems, micro-assembly, precision positioning, and other fields. At present, Japan is in a leading position in this field. Piezoelectric ultrasonic motors have been widely used for automatic focusing of cameras and video cameras, and a large-scale series of products have been formed.

 

With the continuous research and improvement of material technology, and the rapid development of high-tech fields such as electronics, information, aerospace, etc., the production technology and application development of piezoelectric ceramics containing high-intelligence new materials are hot topics of concern. Weifang Jude is the China famous piezoelectric manufacturers, having rich piezoelectric ceramics knowledge. If you want to know more information, contact us now!