What is an ultrasonic transducer sensor?

With the further development of information technology in the chemical, petroleum and hydropower sectors, ultrasonic transducer sensor are widely used in oil level, water level and other liquid level measurement. Utilizing the characteristics of ultrasonic, we know that it can also be made into an ultrasonic ranging transducer. Today, let me explain the ultrasonic sensor and its application further.

Introduction of ultrasonic sensors

Ultrasonic sensors are developed by using the characteristics of ultrasound. Ultrasonic is a mechanical wave with a vibration frequency higher than that of sound waves (20kHz). 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, which can become ray and directional propagation. Ultrasonic waves have a great ability to penetrate liquids and solids, especially in solids that are opaque to sunlight. It can penetrate to a depth of tens of meters. When the ultrasonic wave hits the impurity or the interface, it will produce a significant reflection to form an echo, and it can produce a doppler effect when it hits a moving object. Therefore, ultrasonic testing is widely used in industry, national defense, biomedicine, etc.

Components of an ultrasonic sensor

The ultrasonic level transducer is mainly composed of piezoelectric wafers, which can transmit and receive ultrasonic waves. Low-power ultrasound probes are mostly used for detection. It has many different structures, which can be divided into straight probe (longitudinal wave), oblique probe (transverse wave), surface wave probe (surface wave), Lamb wave probe (Lamb wave), dual probe (one probe reflection, one probe reception) Wait.

Working principle of ultrasonic sensor

When voltage is applied to piezoelectric ceramics, mechanical deformation will occur with changes in voltage and frequency. On the other hand, when the piezoelectric ceramic is vibrated, an electric charge is generated. Using this principle, when an electrical signal is applied to a vibrator composed of two piezoelectric ceramics or a piezoelectric ceramic and a metal sheet, so-called piezoelectric bimorph element, ultrasonic waves will be emitted due to bending vibration. On the contrary, when ultrasonic vibration is applied to the piezoelectric bimorph element, an electrical signal is generated. Based on the above effects, piezoelectric ceramics can be used as ultrasonic sensors. Like ultrasonic sensors, a composite vibrator is flexibly fixed on the base. The composite vibrator is a combination of a resonator and a piezoelectric bimorph element vibrator composed of a metal sheet and a piezoelectric ceramic sheet. The resonator is in the shape of a horn, and the purpose is to effectively radiate the ultrasonic waves generated by vibration and to effectively concentrate the ultrasonic waves in the center of the vibrator.

Ultrasonic sensors for outdoor use must have good sealing properties to prevent the intrusion of dew, rain and dust. Piezoelectric ceramics are fixed inside the top of the metal box. The base is fixed on the open end of the box and covered with resin. For ultrasonic transducer distance measurement used in industrial robots, it is required to have an accuracy of 1 mm and strong ultrasonic radiation.