Technology for direct assembly of SMD components in stretchable textile electronics realized by printing

Abstract

In this article, a novelty direct assembly method for stretchable e-textile electronics based on printed technologies is presented. Presented technology utilizes the assembly of components directly into the wet base layout paste, without any interfacing contact material (such as conductive adhesive). Such assembly reduces the number of technological steps and exhibits more reliable behavior, as the number of interfaces is reduced and the conductive material is highly stretchable. Components are encapsulated using flexible encapsulation and the whole electrical system is realized on a foil, which is then thermo-transferred to the textile substrate. Samples are subjected to the bend test and cyclic stretch tests. Direct assembly is proven to be robust enough, as its increase of resistance during cyclic stretch testing is much lower (17% after 500 cycles) than assembly with isotopically conductive adhesive. Direct assembly also exhibits rapid regeneration of resistance after the end of mechanical load. In addition, a low and sufficient contact resistance of around 100 mΩ is achieved.