| Cardiovascular disease is the number one killer of human health today,its early stage of diagnosis and the onset of treatment are very difficult.The human arterial blood pressure and pressure waveform contains rich information about the heart,blood vessels,blood pressure,etc.,and is an important method for clinically evaluating such diseases.However,most of the current commercial instruments for obtaining continuous arterial pressure waveform are traditional rigid structures.It is difficult to achieve miniaturization,integration and intelligence,and continuous,real-time and long-term monitoring of arterial blood pressure waveform in people's daily life is difficult.In view of this,this subject plans to develop a flexible ultrasonic blood pressure sensor that can be attached to the body surface to achieve non-invasive continuous monitoring of daily blood pressure waveform,providing hardware support for health monitoring and disease prediction smart medical micro-system.First,the structure and function of traditional medical ultrasonic sensors are studied,the principle of noninvasive continuous detection of arterial blood pressure waveform based on pulse-echo method is explored,and the overall structure design of the sensor is completed according to the working principle of the device,including flexible electrode layer and piezoelectric array three partial layers and the adhesive layer,and each of the sensor assembly structural design and materials selected conducted a thorough discussion.Secondly,the simulation software is used for modal analysis and sound field analysis of the sensor;the sensor's emission frequency and directivity are used as targets to optimize the design of the sensor structure and corresponding characteristic parameters;and the sensor's emission power,center displacement amplitude and emission Simulation studies were conducted on relevant performance indicators such as voltage response.The simulation results show that the designed device has a resonance frequency of 2.068 MHz and a transmission power of 7.64 W.Further,based on the device structure and flexibility requirements,using femtosecond laser processing,magnetron sputtering coating,low temperature soldering and other technologies,we successfully prepared the required flexible buckling structure electrode with an electrode elongation greater than 120%;design The assembly scheme of the multi-layer structure of the miniature sensor was studied,and the key process technology of the alignment and connection between the various layers of the device was studied in depth;a flexible ultrasonic miniature sensor was prepared.The impedance of the prepared device was tested,the resonance frequency was 2.05 MHz,and the deviation from the design value was only 0.87%;and the variance of the dynamic parameter test results of each sensor array element was less than 4% of the average value of the test value,with good consistency,Prove that the device manufacturing process has good repeatability.Finally,the pulse-echo method blood pressure detection system was built,and the movement signal collection of the human brachial artery blood vessel wall was completed.The algorithm was designed and the relevant programs were written to complete the identification and extraction of the echo signal feature points of the anterior and posterior walls of the blood vessel.The human artery blood pressure-blood vessel diameter model was compared and analyzed,and the continuous waveform of the human brachial artery pressure was finally obtained,which verified the feasibility of the noninvasive continuous blood pressure detection scheme based on the pulse-echo method.The research results of this topic will provide theoretical guidance and technical support for the establishment of a non-invasive monitoring system for human blood pressure. |
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