Issue link: https://iconnect007.uberflip.com/i/1042925
54 FLEX007 MAGAZINE I OCTOBER 2018 Feature by Corné Rentrop HOLST CENTRE The seamless integration of electronics into flexible, curved, and even stretchable surfaces is being requested for several markets, such as automotive (dashboards, lighting, sensors), smart buildings (lighting facades, air quality, solar panels), medical (health patches, X-ray, analysis), and smart clothing (position track- ing, sports). The requirement for products that are light, take up less space, conformable, and easily integrated into an existing design will result in an improved user interface. Addition- ally, the product should be robust from a cost- effective process consuming less material, and the technology should be consistent with the Internet of Things (IoT) roadmap. The Printed Electronics Concept Printed electronics deliver smart surfaces for applications by creating printed circuits on polymer films and utilizing traditional graphi- cal printing techniques, such as screen printing and inkjet printing, to create the circuitry on foils in sheet or roll form. An obvious advantage of printing electronics is the speed that can be achieved. For example, there is roll-to-roll screen printing equipment at the Holst Centre that runs at a maximum speed of 60 metres per minute, creating seam- less circuits directly onto a roll (Figures 1 and 2). Photonic sintering of the metal ink allows high operating speeds to be maintained at a controlled temperature of approximately 130°C to prevent the foils from melting. In combina- tion with roll-to-roll printing, pick-and-place assembly technology can place electrical com- ponents on the roll. Conductive adhesives are usually used as interconnects. Crossovers and vias can be printed by alter- nating conducting and dielectric layers, which can maintain a PCB-like structure, only now on a roll. All polymer foil materials are suit- able substrates for printed electronics. Polyes- The Shape of Things to Come: Curved, Flexible, Stretchable, and Three-Dimensional Electronics Figure 1: Roll-to-roll printing of circuit on films at a maximum speed of 60 m/min.