What does ultrasonic sensor work

Using the flexural vibration of the conventional piezoelectric bimorph element vibrator, it is impossible to achieve this purpose when the frequency of ultrasonic module distance measuring transducer is higher than 70kHz. Therefore,by high frequency detection, piezoelectric ceramics with vertical thickness vibration mode must be used. In this case, the matching of the acoustic impedance of piezoelectric ceramics with air becomes very important. The acoustic impedance of piezoelectric ceramics is 2.6×107kg/m2s, and the acoustic impedance of air is 4.3×102kg/m2s. The difference of 5 powers will cause a lot of loss on the vibration radiation surface of piezoelectric ceramics. A special pzt material is adhered to piezoelectric ceramics as an acoustic matching layer to match the acoustic impedance of air. This structure can enable the ultrasonic sensor to work normally at frequencies up to hundreds of kHz.

Application of ultrasonic sensors

Ultrasonic sensing technology is applied in different aspects of production practice, and medical application is one of its most important applications. The following technology uses medicine as an example to illustrate the application of high frequency ultrasonic transducer . 

The application of ultrasound in medicine is mainly to diagnose diseases, and it has become an indispensable diagnostic method in clinical medicine. The advantages of ultrasound diagnosis are no pain, no damage to the subject, simple method, clear imaging, high diagnostic accuracy, etc. Therefore, it is easy to promote and is welcomed by medical workers and patients. Ultrasound diagnosis can be based on different medical principles. Let's take a look at one of the representative so-called A-type methods. This method uses the reflection of ultrasound. When ultrasonic waves propagate in human tissue and encounter two media interfaces with different acoustic impedances, reflected echoes are generated at the interface. When it is encountering a reflective surface, the echo is displayed on the screen of the oscilloscope, and the impedance difference between the two interfaces also determines the amplitude of the echo.

In industry, the typical applications of custom ultrasonic transducer are non-destructive testing of metals and ultrasonic thickness measurement. In the past, many technologies were hindered because they were unable to detect the inside of the object's tissues. The emergence of ultrasonic sensing technology changed this situation. Of course, ultrasonic sensors are fixedly installed on different devices to quietly detect signals that people need in the future.

In application, ultrasound will be combined with information technology and new material technology, and more intelligent and highly sensitive ultrasonic sensors will appear. In future life, the role of ultrasonic sensors will become more and more important.