Life Cycle Assessment of Paper Based Printed Circuits

Abstract: Printed circuit boards have been massively manufactured and wildly used in all kinds of electronic devices during people’s daily life for more than thirty years since the last century. As a highly integrated device mainly consists of silicon base, an etched copper layer and other soldered components, massive production of printed circuit boards are considered to be environmentally unfriendly due to the wet chemical manufacturing mode and lack of recycling ability. On the other hand, the newly invented ink jet printing technology enables cost-effective manufacturing of flexible, thin and disposable electrical devices, which avoid acid etching process and lead to less toxic emissions into the environment. It is important to consider life cycle analysis for quantitative environmental impact evaluation and comparison of both printed circuit boards and printed electronics to enhance the sustainability of a new technology with product design and development. This thesis first reviews the current approaches to conventional and modern printing methods, as well as the state-of-the-art analysis of sustainability and environmental assessment methodologies. In the second part, a typical ink jet printed electronic device is introduced (an active flexible cable for wearable electrocardiogram monitoring). This active cable is designed for the interconnection between bio electrodes and central medical devices for bio signal transmission. As the active cable consists of five different metal transmission traces which are formed by printing conductive ink onto paper substrates, different shielding methods are investigated to ensure high quality bio signal transmission. Specifically, the results prove that passive shielding methods can significantly decrease the cross talk between different transmission traces, enabling the transmitting of bio signals for wearable ECG monitoring. This research also explores environmental issues related to printed electronics. For the full life cycle of printed electronics, we focused not only on quantitative environmental emissions to air, fresh water, sea and industrial soil, but also on resource consumption and impacts analysis. Finally, comparative environmental performance evaluation of traditional cables and ink jet printed active cables are made to examine the environmental impact and sustainability of both technologies, and the results show the strengths and weaknesses of each technology by analysis and assessment.