Chinese and American researchers have developed thin flexible circuit boards that can be used as

WASHINGTON, August 13 (Xinhua) - Circuit boards are usually very hard, but researchers from the United States and China have collaborated to develop a lightweight and soft circuit board, which has been conceptually validated as an "intelligent bandage" that can be applied to the skin to monitor various physiological signals.
The cover article published on the 13th in the UK's Nature Electronics magazine showed that this "smart bandage" is composed of four layers of interconnected thin flexible circuit boards stacked together, with an overall size and thickness similar to a 1 yuan coin.
Researchers say that circuit boards use a "island bridge" structure based on silicon elastomers, where "islands" are rigid small electronic devices such as sensors, antennas, Bluetooth chips, etc; A "bridge" is a stretchable copper wire used to connect "islands", allowing circuit boards to stretch and bend without affecting their functionality.
Xu Sheng, the corresponding author of the paper and professor of nanoengineering at the University of California, San Diego, USA, said that the design difficulty is not stacking circuit boards, but rather achieving current connections between circuit boards.
Xu Sheng's team found that traditional lithography and etching techniques are not suitable for scalable elastomers. Therefore, they mixed silicon elastomers with black organic dyes, made circuits and stacked them, welded them using lasers, and finally filled them with conductive materials. The circuit board obtained in this way not only has normal functions but also has the elasticity that traditional circuit boards lack.

Researchers say that the "smart bandage" made of this flexible circuit board has a wide range of uses and can be applied to different positions of the body to record electrocardiogram, electroencephalogram, eye movements, and muscle behavior.
In addition, it can achieve wireless communication with smartphones or laptops within 10 meters, and can also be used for remote control of robotic arms.
The researchers stated that after 6 months of continuous use, the circuit performance and scalability of the device did not decrease.
Researchers from China University of Electronic Science and Technology and the US Air Force Research Laboratory participated in the research.