Issue link: https://iconnect007.uberflip.com/i/1108006
70 FLEX007 MAGAZINE I APRIL 2019 Article by Pete Starkey I-CONNECT007 Of all of the technical user presentations I attended at the AltiumLive design summit in Munich, the one I found most fascinating intro- duced an innovative technology that encour- aged a bit of lateral thinking and appealed to my creative side. "IMSE: Creating Smart Sur- faces with Electronic Functionality" was the title of the presentation by Sini Rytky, VP of product management, and Tuomas Heikkilä, senior hardware specialist, both from TactoTek in Finland. Rytky explained that IMSE stood for injec- tion-moulded structural electronics—a tech- nique for integrating flexible printed circuitry and electronic components into three-dimen- sional moulded structures with touch-sensitive functional surfaces, using standard high-speed manufacturing methods and equipment. The IMSE manufacturing process was logical and straightforward in concept. Starting with a flat thermoplastic film—typically a polyure- thane or an in-mould labelling film—standard printed-electronics techniques were used to apply conductive features such as circuitry, touch controls, and antennas as well as dec- orative features and user-interface graphics. Surface-mounted components and LEDs were added by standard pick-and-place techniques while the substrate was still flat—presumably using conductive adhesive, although this was not disclosed. Then, the assembly was ther- moformed into a three-dimensional shape and injection-moulded to form a thin, lightweight, functional unit with a smart, touch-sensitive surface and all of the electronics fully encapsu- lated and embedded. Of the numerous poten- tial application areas, the most obvious was the integration of touch controls into automo- tive interior trim. Designs could incorporate one or two films with electronics on one or both. Rytky showed an example of the stackup for a two-film struc- ture. The top surface layer was an in-mould labelling film—although it could have been a natural material like leather or wood—printed with decorative inks. Next, came the first elec- tronic layer, which was printed with conduc- tive and dielectric inks and assembled with SMT components. At the centre of the stack was a layer of thermoplastic resin, polycarbon- ate, or polyurethane; then, the second elec- tronic layer; and finally, an in-mould labelling film. Rytky stressed that the essence of IMSE Creating Smart Surfaces with Electronic Functionality