With the rapid development of science and technology, it is not difficult to find the application of ultrasonic sensors in real life. Ultrasound sensors are widely used in manufacturing, electric power, metallurgical measuring building materials, chemical industry, grain, automobile, warehousing, ship, textile, transportation, exploration, liquid level, level monitoring, open ditch flow detection, robotic food processing and other industries because of their high measurement accuracy, stable operation and temperature compensation function. Level measurement in solid material industry.

Ultrasound is widely used, but as the saying goes, no one is perfect. From our previous understanding and experience of the use of ultrasonic sensors, do they have any advantages and disadvantages? Will these advantages and disadvantages bring some impact on our lives? These are what we need to pay attention to when we deeply understand the ultrasonic sensors. Next, we explore this issue.

First of all, we will talk about the working principle of the ultrasonic sensor: the ultrasonic sensor is a sensor developed by using the characteristics of ultrasound. The ultrasonic probe is mainly composed of piezoelectric wafers, which can emit and receive ultrasound. In fact, piezoelectric ultrasonic generator works by the resonance of piezoelectric crystal. It has two piezoelectric wafers and a resonant plate. When the frequency of the external pulse signal at its two poles equals the natural oscillation frequency of the piezoelectric wafer, the piezoelectric wafer will resonate and drive the resonant plate to vibrate, and then produce ultrasonic wave. Conversely, if no voltage is applied between the two electrodes, when the resonant plate receives the ultrasonic wave, the piezoelectric wafer will be compressed to vibrate, and the mechanical energy will be converted into electrical signals, then it will become an ultrasonic receiver. Low power ultrasonic probes are mostly used for detection. They have many different structures. They can be divided into straight probe (longitudinal wave), oblique probe (shear wave), surface probe (surface wave), Lamb wave probe (Lamb wave), double probe (one probe reflects, one probe receives).

Secondly, there are many advantages in measuring objects by using the characteristics of ultrasound, because ultrasound 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. The sensor based on ultrasonic characteristics is called "ultrasonic sensor", which is widely used in industry, national defense, biomedicine and so on.

However, because the Curie point of piezoelectric materials is generally higher, especially the power of ultrasonic probe used in diagnosis is smaller and the working temperature is lower, it can work for a long time without failure. The temperature of medical ultrasound probe is relatively high, so it needs separate refrigeration equipment. Sensitivity depends mainly on the chip itself. The electromechanical coupling coefficient is large and the sensitivity is high; on the contrary, the sensitivity is low. There are three reasons:

1. Driving voltage is relatively high, generally between 100Vp-p and 1500Vp-p. Pulse transformer boost is needed in many low voltage equipments, but it also brings some complicated problems. It would be better if there were sensors with 3-5V low-voltage drive (higher power);

2. Nowadays, the frequencies of ultrasonic sensors are relatively fixed. For example, 40KHz sensors can only be used on 38-42KHz. Other frequencies are similar. At present, there are few sensors with wide frequency range, such as 40KHz-500KHz products.

3. Sensitivity should be higher.

It can be seen that ultrasonic sensors can emit, receive and analyze sounds that our ears cannot detect. In the detection aspect, the use of ultrasonic sensors can achieve the functions of ultrasonic ranging, ultrasonic flaw detection, and can be used to detect submarines, enemy submarines and display metal internal injuries. These technologies can be applied in industry, agriculture, light industry and medical treatment, and are closely related to our lives.