Conformable Electronics: Integration of electronic functions into static and dynamic free form surfaces

The ongoing miniaturization at different levels seems to be an constant in electronics development. It allows not only to increase in functionality in novel product generations, but also the spreading of electronics into new environments. In recent years, especially the application of electronic functions close to or onto the human skin (i.e. by textiles or band aids), implants and novel biomorphic user interfaces have attracted considerable development efforts. It turns out, however, that miniaturization alone does not cover all requirements in the indicated application fields. Typical systems consist of sensors/actuators, data processing and transmission, and quite often relatively bulky power supplies. In order to meet the mechanical requirements of novel products (softness, drapability), miniaturized system elements are laterally distributed and interconnected by appropriate wiring architectures. A common feature of the above indicated application cases is the conformation of the distributed electronic systems to three-dimensional free form surfaces, which are either dynamically moving (human skin) or static. In order to conform to different types of surfaces the systems typically need to sustain a certain elongation repeatedly (in dynamical applications) or at least once during a forming process. At Fraunhofer IZM a portfolio of technologies, summarized as conformable electronics, has been developed, encompassing textile, stretchable circuit boards, paste printed and thermo-formable electronics on a variety of dielectric carrier materials. Each technology provides on one hand the electrical interconnection network and on the other hand technologies to assemble, interconnect and encapsulate electronic components thereon. Having been developed separately it turned out, that combination of the technologies are possible which leads to a number of synergies and extended of application potentials.