Design And Application Of Flexible Bluetooth Sensor System Based On Integrative Printing Method

Flexible wearable electronics is one of the important consumption demands at present.However,due to the all flexible electronics are still in the primary research,their performances and reliabilities are not ready for the application.Considering the miniaturization of silicon-based chips,it’s an important choice to combine flexible printed circuits with traditional silicon-based electronics for better application and development.In this thesis,the printed flexible BLE hybrid circuit has been designed,carried on experiments,and fabricated for wearable sensors application.The main research contents are listed as follows.(1)The principle of self-powered triboelectric device was analyzed according to its self-powered characteristics and the nature of signal transmission.Then a flexible self-powered device combined with a Bluetooth Low Energy(BLE)chip(DA14580),which can obtain touch signal,is prepared on polyimide(PI)film.On the other hand,studies were focused on selection and treatment of the substrate,conductive silver paste and the process parameters for the integrative printing method and actual requirements of the flexible circuit.The silver paste was proved to meet the demands of the conductivity,viscosity and flexibility finally for application.(2)A Bluetooth antenna based on a flexible printed circuit was designed and fabricated.Firstly,the structure design and performance simulation of the antenna was carried out.Then,the screen-printing technology was used to fabricate the inverted-F structure Bluetooth antenna on the flexible PI substrate,and the oxidation resistance and bending resistance performance tests were also performed.The results show that the antenna still covers the Bluetooth frequency band(2.4-2.485GHz)after oxidation and bending tests,which means it meets the requirements of use.(3)Aiming at small size,flexibility and low power consumption,a practical wearable Bluetooth circuit system is designed and fabricated based on flexible hybrid circuit manufacturing technology.The integration method of flexible circuits and silicon-based electronic chips were researched,as well as the preparation of complex flexible hybrid circuits.The result confirmed that the integration between microchips with high-density pins and flexible printed circuits was reliable.Finally,a flexible hybrid circuit that integrates silicon sensors(including temperature sensor,heart rate sensor),low-power Bluetooth SOC,flexible Bluetooth antennas and self-powered devices has been integrated based on an integrative printed circuit.The sample can measure human physiological parameters with Bluetooth signal transmission.As an applied study focusing on flexible wearable electronics,this thesis prepared a flexible BLE wearable sensing system successfully.The flexible system can monitor the human body temperature with a resolution of 0.0625℃,and the heart rate within one time/min difference.And the flexible triboelectric sensor can also generate and send signal when it is touched.The data from sensors can be sent to mobile terminal based on the low energy BLE protocol.The research contents of this thesis open up possibility of the application of flexible wearable electronic products with low energy cost.