The board is usually very hard, but the US and Chinese researchers have collaborated to develop a thin, flexible circuit board that is proof-making as a 'smart bandage' that can be attached to the skin to monitor multiple physiological signals. According to a cover article in the British journal Nature Electronics, this 'smart bandage' is a stack of four layers of interconnected thin flexible boards. The overall size and thickness are similar to those of a 1-dollar coin.
The researchers say that the board uses a silicon-elastomer-based 'island-bridge' structure, where 'islands' are rigid small electronic devices such as sensors, antennas, Bluetooth chips, etc.; 'bridge' is stretchable copper Line, used to connect 'island', so that the board can be flexed and bent without affecting its function.
The author of the paper, Xu Sheng, a professor of nanoengineering at the University of California, San Diego, said that the design difficulty is not to stack the boards, but to make the current connections between the boards.
Xu Sheng team found that traditional lithography and etching techniques are not suitable for retractable elastomers. Therefore, they mix silicon elastomers with black organic dyes, make circuits and stack them, use lasers for soldering, and finally fill conductive materials. The board thus obtained has both normal functions and flexibility that is lacking in conventional boards.
Researchers say that 'smart bandages' made from this flexible circuit board are versatile and can be placed in different parts of the body to record ECG, EEG, eye movements and muscle behavior.
In addition, it can communicate wirelessly with a smartphone or laptop within 10 meters, and can also be used to remotely control the robotic arm.
The researchers said that after six months of continuous use, the circuit performance and scalability did not decrease.
Researchers from China University of Electronic Science and Technology and the US Air Force Research Laboratory participated in the research.
