Capacitive micromachined ultrasonic transducer (CMUT) is a new type of ultrasonic transducer The research results in mainland China are increasing
Capacitive micromechanical ultrasonic transducer (CMUT) is a device for ultrasonic testing based on the principle of capacitive sensing and micromechanical (MEMS) technology.
CMUT is a multi-layer structure, which includes a substrate, a vibrating film, a capacitor, etc. The working principle of CMUT is that in the transmitting state, the DC voltage is applied to generate an electric field, so that the vibrating film undergoes simple harmonic vibration to produce ultrasonic waves, and in the receiving state, the vibrating film receives ultrasonic waves, and is vibrated by sound pressure, causing the capacitance value of the capacitor to change, and the ultrasonic detection is realized by detecting the change of capacitance value, and the sound energy is converted into an electrical signal for output.
The function of an ultrasonic transducer is to convert electrical energy into sound energy. Traditional ultrasonic transducers are made of piezoelectric ceramics, which have problems such as low consistency and difficulty in forming arrays. According to the "2024-2029 China Capacitive Micromechanical Ultrasonic Transducer (CMUT) Industry Market In-depth Research and Development Prospect Forecast Report" released by the Xinsijie Industry Research Center, CMUT is a new type of ultrasonic transducer with wide frequency bandwidth, high energy conversion efficiency, high receiving sensitivity, high detection accuracy, easy to form arrays (high-density, small-size arrays can be manufactured), can be integrated with CMOS, can be miniaturized, The characteristics of low mass production cost have been widely studied internationally.
Ultrasound diagnosis is an important part of medical imaging technology, which has the advantages of non-invasive, intuitive results, wide range of application, low cost, etc., and has a high market penetration rate. With the continuous progress of medical technology, precision medicine has become a development trend, and the requirements for high definition of medical imaging are increasing.
In addition, high-intensity focused ultrasound (HIFU) can also be realized based on CMUT, which can be used in the field of tumor treatment, using the heat generated by high-intensity ultrasound to necrosis tumor tissue. In addition to the medical field, CMUT can also be used in biosensing, biometrics, chemical sensing, underwater ultrasound, etc., and is widely used in electronic appliances, instrumentation, industrial non-destructive testing, military defense and other fields.
Industry analysts said that the mainland government is paying more and more attention to CMUT. In the 2023 National Key R&D Program "Basic Scientific Research Conditions and R&D of Major Scientific Instruments and Equipment", it is proposed to develop capacitive micromechanical ultrasonic transducer arrays, and break through key technologies such as MEMS ultrasonic transducer chips, ultrasonic transducer linear arrays, and high-precision and low-stress processing of all-silicon diaphragms.
The number of CMUT-related journal papers published in mainland China is increasing rapidly, and the main research institutions are North University of China and Tianjin University. In 2023, North University of China cooperated with the Institute of Electronic Engineering of the Chinese Academy of Engineering Physics to design a wideband CMUT that can be used to actively detect objects more than 20cm away from itself, and the related research results were published in the journal "Micro/Nano Electronics Technology".