Ultrasonic Transducer Applied to Electronic Sphygmomanometer

Ultrasonic transducer is one of the key components of medical ultrasonic equipment, and its characteristics directly affect or even limit the performance of the entire equipment. With the continuous development of piezoelectric materials and MEMS technology, small size, light weight, wide frequency band, high resolution, high frequency, and high sensitivity will be the main development direction of medical ultrasonic transducers in the future.


1. High-frequency capacitive micro-machined ultrasonic transducer


At present, the clinical requirement for ultrasonic transducers is to be able to obtain higher frequencies with smaller devices. The capacitive micro-machined ultrasonic transducer of the ultrasonic probe prepared by MEMS technology is easier to array than the ordinary piezoelectric ceramic ultrasonic probe, and the acoustic impedance is close to that of water, with strong penetrability, small size, and high frequency. The human body is scanned, playing an increasingly important role in the field of medical imaging. Capacitive micro-machined ultrasonic transducers have overcome many shortcomings of traditional piezoelectric ultrasonic sensors and have the advantages of high sensitivity, wide frequency band, easy manufacture, low self-noise, wide operating temperature range and easy electronic integration, etc., and has a tendency to replace traditional piezoelectric ultrasonic sensors, and has broad application prospects in the field of medical imaging.


2. Application of ultrasonic transducer in electronic sphygmomanometer


The medical ultrasonic transducer is used to receive the pressure of the blood vessel. When the airbag pressurizes the blood vessel, the ultrasonic transducer cannot feel the pressure of the blood vessel because the applied pressure is higher than the vasodilation pressure; and when the airbag is gradually deflated, the ultrasonic transducer will not feel the pressure of the blood vessel. When the pressure of the blood vessel decreases to a certain value, the pressure of the two reaches a balance. At this time, the ultrasonic transducer can feel the pressure of the blood vessel, which is the systolic pressure of the heart, and an indication signal is sent through the amplifier to give the blood pressure value. The electronic sphygmomanometer can reduce the labor intensity of medical staff due to the cancellation of the stethoscope.


Telemetry and remote control In toxic, radioactive and other harsh environments, people cannot work close to work and need remote control. Electrical switches such as TV sets, electric fans, and electric lights need remote control. When the receiving transducer on the control system needs to be received, the acoustic signal is converted into an electrical signal to make the switch act. The application of medical ultrasonic transducer in the medical industry: Ultrasonic weight loss, using the cavitation effect of ultrasonic transducers and micro-mechanical vibrations, to crush and emulsify excess fat cells under the human skin and excrete them to achieve the purpose of weight loss and shaping.


At present, in response to the clinical demand for medical high-frequency ultrasonic transducers, high-frequency ultrasonic transducers made of piezoelectric PZT thick films, relaxor ferroelectric single crystal materials, composite piezoelectric materials, and lead-free piezoelectric materials are used. Ultrasonic transducers have become a research hotspot in the field of biomedicine. With the development of micro-electro-mechanical system technology, the wide application of high-frequency capacitive micro-machined ultrasonic transducers in future clinical practice has become an inevitable trend.

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