Ultrasound sensor is a kind of sensor based on the characteristics of ultrasound. Ultrasound is a kind of mechanical wave whose vibration frequency is higher than that of sound wave. It is generated by the vibration of transducer wafer under the excitation of voltage. It has the characteristics of high frequency, short wavelength, small diffraction phenomenon, especially good direction and directional transmission.
Ultrasound has great penetration ability to liquid and solid, especially in sunlight opaque solids, which can penetrate tens of meters deep. When ultrasound touches impurities or interfaces, it will produce significant reflection and form echoes. When it touches a moving object, it will produce Doppler effect. Therefore, ultrasonic testing is widely used in industry, national defense, biomedicine and other areas. Ultrasound as a means of detection must produce and receive ultrasound. The device to accomplish this function is the ultrasonic sensor, which is customarily called the ultrasonic transducer, or the ultrasonic probe.