Performance Indicators Ultrasonic Distance Sensor

Ultrasonic distance sensor can be widely used in related fields such as level, liquid level, monitoring, robot anti-collision, various ultrasonic proximity switches and anti-theft alarms. It is reliable in the operation, easy to install, waterproof, with small angle of launch, high sensitivity and convenience. It is connected to an industrial display instrument and also provides a probe with a large angle of emission. The designing principle of the ultrasonic distance sensor is that the ultrasonic sensor is a sensor developed by utilizing the characteristics of ultrasonic waves. Ultrasonic wave is a kind of mechanical wave with a vibration frequency higher than that of sound waves. It is generated by the vibration of the transducer wafer under the excitation of voltage. It has high frequency, short wavelength, small diffraction phenomenon, especially good directivity can be ray oriented. Characteristics such as communication. 

Ultrasonic waves have a great ability to penetrate liquids and solids, especially in the sunlight-opaque solids, which can penetrate depths of several tens of meters. When an ultrasonic wave hits an impurity or an interface, it will produce a significant reflection to form a reflection into an echo, which can produce a doppler effect when it hits a moving object. Therefore, ultrasonic testing is widely used in the industrial, national defense, biomedical and other fields. Ultrasound is used as a detection means, and ultrasonic waves and ultrasonic waves must be generated. The device that performs this function is ultrasonic distance measurement sensor, which is customarily called an ultrasonic transducer or an ultrasonic probe. Ultrasonic distance sensor performance indicators, the core of the ultrasonic probe is a piezoelectric film in its plastic jacket or metal jacket. There are many kinds of materials constituting the wafer.The size of the wafer, such as diameter and thickness,it is different, so the performance of each probe is different. We must know its performance before using. The main performance indicators of ultrasonic sensors include the following aspects.

2. Working temperature.
Since the curie point of the piezoelectric material is generally high, in particular, the diagnostic ultrasonic probe uses less power, so the operating temperature is lower and can work for a long time without causing failure. Medical ultrasound probes are relatively hot and require separate refrigeration equipment.

It mainly depends on the manufacturing of the wafer itself. The electromechanical coupling coefficient is large, the sensitivity is high, and the sensitivity is low. The working of ultrasonic distance sensor structure of voltage is applied to piezoelectric ceramics, which will cause mechanical deformation with the changes in the voltage and frequency. On the other hand, an electric charge is generated when the piezoelectric ceramic is vibrated. With this principle, when a vibrator is composed of two piezoelectric ceramics or a piece of piezoelectric ceramic and a metal piece is called a bimorph element, an ultrasonic signal is emitted due to bending vibration when an electric signal is applied. Conversely, when ultrasonic sensor to measure distance is applied to the bimorph element, an electrical signal is generated. Based on the above effects, piezoelectric ceramics can be used as an ultrasonic sensor. Like an ultrasonic sensor, a composite vibrator is flexibly fixed to the base. 

The composite vibrator is a combination of a resonator and a bimorph vibrator composed of a metal and a piezoelectric ceramic . The resonator is horn-shaped to effectively radiate ultrasonic waves generated by vibration and to effectively concentrate the ultrasonic waves in the central portion of the vibrator. Ultrasonic sensors must have good sealing to prevent ingress of dew, rain and dust outdoor. The piezoelectric ceramic is fixed on the inner side of the top of the metal case. The base is fixed to the open end of the case and covered with a resin.For ultrasonic distance sensor datasheet,which is used in industrial robots, accuracy is required to be 1 mm and strong ultrasonic radiation is required. With the bending vibration of a conventional bimorph element vibrator, it is impossible to achieve this at a frequency higher than 75 kHz. Therefore, piezoelectric ceramics of vertical thickness vibration mode must be used in the high frequency detection. In this case, the matching of the acoustic impedance of the piezoelectric ceramic with the air becomes important. The acoustic impedance of the piezoelectric ceramic is 2.6 x 107 kg/m2s and the acoustic impedance of air is 4.3 x 102 kg/m2s. The difference can result in a large loss on the surface of the piezoelectric ceramic vibrating radiation. A special material adheres to the piezoelectric ceramic as an acoustic matching layer to match the acoustic impedance of the air. This structure allows the ultrasonic sensor to still operate normally at frequencies up to 100 kHz.