Electronics in Textiles – Adhesive Bonding Technology for Reliably Embedding Electronic Modules into Textile Circuits

The interconnection of electronics and textile circuits is still a main challenge for the fabrication of reliable smart textiles. This paper investigates the thermoplastic adhesive bonding technology. Electronic modules are bonded to textile substrates with a thermoplastic non-conductive adhesive (NCA) film. The modules are placed onto textile circuits with an NCA-film in-between. By applying pressure and heat, the adhesive melts and contact partners touch. Subsequently cooling solidifies the NCA resulting in an electrical and mechanical contact of the electronic module and the textile circuit. This paper shows the suitability of this technology for knitted, woven, non-woven and embroidered fabrics with metal coated yarns as well as with litz-wires as conductors. Besides, it shows that the interconnection process works well with thermoplastically insulated conductors. In addition, the design of interposers has been improved in respect to contact formation and miniaturization compared to previous publications. The pitch of the contact pads is set to 1.27 mm. A textile display was realized with smart RGB-Pixels, which are controlled by an I²C-bus on a quadrupolic woven substrate. It demonstrates the applicability and the potential of this technology.