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112 DESIGN007 MAGAZINE I SEPTEMBER 2020 Next-Generation Flex Circuits: Textile Base Flex The COVID-19 pandemic remains active throughout the world as Phase 3 clinical tri- als are underway for many pharmaceutical companies. Large R&D investments from Big Pharma could bear fruit in the coming months as the race for a vaccine continues. Several equipment manufacturers are developing medical devices for both diagnosis and treatment to fight COVID-19. This market could be huge in the near future. Medical electronics is already a big segment of the industry. New medi- cal devices will require different performance standards than typical consumer electronics, such as smartphones, especially when attached to your body. These new wearable electronic devices require comfort as well as reliability. The device's base material must be elastic and per- meable to allow air and moisture to pass through it while addressing aller- gies and skin irritations. Traditional flexible dielectric materials, such as polyimide and PET films, are not suitable to satisfy these medical requirements. Traditional electronics devices focus on performance from stable substrates, and characteristically have high dimensional stability, no permeability, low moisture absorption, and high insulation resistance. This will not work for most of the wearable electronic medical devices, so where do we go from here? An assortment of textiles was developed over the years purely out of necessity (the mother of all inventions). There are many fibers that are stretchable and perme- able, and more than one could be suitable to use in wearable medical devices. Creating electronic circuits on fabric sub- strates is not easy. The subtractive processes in manufacturing use wet chemicals. This causes an adverse reac- tion with textiles, so a dry process is needed of generating circuits o n t h e t ex t i l e s u b - strates. I am experi- enced with two types of dry processes: a die stamping process, and screen-printable thick- film circuits. The die-stamping process uses a specially formed punching die to cut the copper foil with glue and bond the circuits onto textile sub- strates—a completely dry process. (Feel free to reach out to me for details on this technology). EPTE Newsletter by Dominique K. Numakura, DKN Research LLC