Piezoelectric ceramics are widely used in aerospace, electronics, computers, laser, ultrasound, energy and other fields. The application of piezoelectric ceramics is mainly divided into two categories; piezoelectric vibrator and piezoelectric transducer. The former are such as oscillators, resonators, filters, and delays. These devices mainly use the principle of electric-mechanical and mechanical-electrical energy conversion to work, requiring stable piezoelectric, dielectric, and elastic properties, and high mechanical quality factors . The latter, such as microphones and ultrasonic transducers, are mainly used for energy conversion and require high electromechanical coupling coefficients and quality factors.
1. Application on high voltage generating device
The high-voltage generating device is a high-voltage generating element made of the electromechanical conversion characteristics of piezoelectric ceramic materials.
(1) Piezoelectric ceramic igniter
Piezoelectric ceramic igniter is a device that uses piezoelectric ceramics to convert mechanical force into electric spark. The principle of piezoelectric ceramic igniter generates high-voltage power. It uses piezoelectric ceramic elements to undergo elastic deformation by mechanical force to generate high-voltage output. High-voltage spark discharge ignites flammable fuel gas. Piezoelectric ceramic igniters include piezoelectric lighters, piezoelectric high-voltage generators and household piezoelectric ceramic igniters.
Piezoelectric ceramic igniter
(2) Piezoelectric ceramic transformer
Piezoelectric ceramic transformer is a device that uses the secondary conversion of piezoelectric ceramic electric energy→mechanical energy→electric energy to obtain the highest boost output at the resonance frequency. The principle is that when an alternating electric field of a certain frequency is applied to the driving part, mechanical deformation is generated by the inverse piezoelectric effect, which causes mechanical resonance and propagates along the length of the ceramic sheet. This mechanical resonance, through the positive piezoelectric effect, causes the end face of the power generation part of the ceramic chip to gather a large amount of bound charge; the more the bound charge is, a relatively high voltage output is obtained on the end electrode of the power generation part.
The material used to make piezoelectric ceramic transformers should have high electromechanical coupling coefficient, especially the transverse electromechanical coupling coefficient. The coupling coefficient with longitudinal electromechanical is high. The thermal stability of the material should be good to prevent heat loss, and the mechanical quality factor should be appropriately high, which requires good frequency temperature stability and time stability. In addition, it must have sufficient mechanical strength and high AC field strength.
Piezoelectric transformer applications include continuous ignition devices, high-voltage power converter multilayer composite structure piezoelectric ceramic transformer and so on.
Piezoelectric ceramic transformer
(3) Other applications
Such applications include remote piezoelectric signal generators, such as wired remote control, ultrasonic remote control, wireless remote control, and electro-optical remote control. Piezoelectric button switches, in most electronic devices such as electronic computers, there are actions to start or stop, and piezoelectric switches can be used obtain a lightweight non-contact switch.
Piezoelectric power switch, which is a switching element composed of piezoelectric ceramic elements and amorphous semiconductors. In addition, there is a portable small power supply (power charger), which can use piezoelectric ceramics to generate electricity to charge the battery for the second time without changing the battery.