In this paper, we present the concept and describe the miniaturized packaging of a textile integrated wireless body-area-network (WBAN) node. The electronic modules have been laminated onto a textile antenna, by applying cutting edge integration technologies. The designed 868MHz UHF antenna is wrapped around the electronic module and consists of two layer of textile. Moreover, a layer of conductive textile has been mounted on a layer of non-conductive textile. For the mechanical and the electrical connection we have employed a thermoplastic non-conductive adhesive (NCA) and an isotropic conductive adhesive (ICA). The uniqueness of this process is to demonstrate how the electronic module was placed inside a textile UHF antenna. Precise packaging is important to avoid the negative effects of electronic components inside an UHF environment. The reliability of the mechanical and electrical connection of the electronic modules was tested. These tests were used to evaluate the adhesion strength between the electronic module and the base fabric (non-conductive textile). Moreover, they provided information about the contact resistance between the conductive textile and the antenna feed lines of the electronic module. Additionally, performed cross sections and X-Ray photography provided more insight in the reliability. The achieved results demonstrate the successful operation of the designed System in Package (SiP), consisting of an electronic module attached to a textile UHF antenna.
This document explains different approaches to integrating electronics in textiles. It discusses reliability standards and tests for electronics in textiles. Encapsulation technologies are evaluated concerning their applicability in textile integrated electronics.Furthermore a specific assembly with embroidered wiring and embroidered interconnections has been developed and improved. Two different encapsulation technologies have been developed for this assembly. Standardized tests have been carried out to assess the reliability of the assembly and its encapsulations. Finally the achievements are critically discussed.
An innovative technology for the mass production of stretchable printed circuit boards (SCBs) will be presented in this paper. This technology makes it possible for the first time to really integrate fine pitch, high performance electronic circuits easily into textiles and so may be the building block for a totally new generation of wearable electronic systems. An overview of the technology will be given and subsequently a real system using SCB technology is presented.
Commonplace electronic appliances for consumer or industrial use are still mostly rigid or at maximum flexible entities. The flexibility of foldable units like laptops or cell phones is usually realized through flexible circuit board (FCB) interconnectors. Although flexibility allows for considerably enhanced degrees of freedom in design, it is not compatible with more complex three dimensional curvatures and dynamics thereof. In the past years a number or approaches to realize stretchable electronic circuits in order to reach beyond unidirectional bending or folding of electronics have been reported. In the frame of the European Project STELLA a particular fabrication technology for stretchable electronic systems has been developed at Technische Universitaet Berlin. This technology, termed ?stretchable circuit board? (SCB) technology, is derived from conventional printed circuit board manufacturing. Stretchability of the boards is enabled by (i) using polyurethane instead of FR4 or polyimide as a carrier material of the copper structures and (ii) a meandering design of the Cu interconnects between commercial (rigid) electronic components. Such boards can be (once) extended by up to 300% before fracture of the Cu interconnections. For repeated elongation/relaxation cycles elongations with a few percent are allowable in order reach high cycle numbers. Electronic components are assembled after local application of a solder mask and surface finish for solderability. The electronic interconnection is established using a low temperature solder alloy (SnBi, Tm=142?C). For protection and enhanced system robustness all components are subsequently encapsulated within a polyurethane capping. Systems thus realized can be readily attached to different kinds of surfaces. Most interesting for various application cases is the easy attachment to textile substrates by a simple lamination process. The field use case studies of stretchable systems in the frame of the STELLA are mostly- sensor applications in the field of medical electronics like a breathing frequency monitor for babies, a shoe insole pressure sensor for diabetes patients, or a band aid inlay to measure pressure and humidity of an acute wound when pressure therapy is applied. The latter application will be described in more detail since different aspects of bio-medical applications can be explained with this example. Another emerging field of applications is textile electronics, where it has been proven, that stretchable electronics can serve a versatile building blocks for complex electronic systems integrated in textiles.
Permanently installed RFID tags in textiles have become a research topic of great interest in the industry. They could revolutionize the market and the daily life. Requirements for such tags are extremely high. They have to be non-obtrusive, very durable and cheap. This paper will describe a novel package and system layout that offers all these characteristics for applications which require domestic washing (e.g. clothing), but also for technical textiles. Results of different reliability tests will be presented, to prove the high durability of the developed package.
Today's electronic systems are based on an assembly of components onto rigid or flexible substrates, serving perfectly the needs of traditional product fields like automotive, computing or industry electronics. On the other hand, many of the demands from emerging applications like wearable and textile electronics cannot be met if standard technologies are used for their realization. These new fields have therefore become mayor drivers for the development of novel technologies. Among these 'stretchable electronics' have attracted strong attention. Especially for textile applications the potential of electronic systems to comply with the body shape and movement will improve the user comfort dramatically. A manufacturing technology for the realization of stretchable systems by common printed circuit board techniques, based on polyurethane as a stretchable matrix material has been developed. The stretchable circuit board technology has been used to realize a number of textile applications. As an example the realization of a fashion dress with integrated high brightness LEDs and movement sensing will be described.
Assembly of electronic components on rigid and/or flexible printed circuit boards is today the customary way to fabricate electronic systems in stationary, mobile and automotive applications. On the other hand, many of the demands from emerging application fields like wearable and textile electronics cannot be met if with standard technologies. These fields have therefore become mayor drivers for the development of novel technologies. Among these dasiastretchable electronicspsila have attracted much attention recently. Especially for textile applications the potential of the electronic system to comply with the body shape and movement will considerably improve the user comfort. In this paper we will present a cost effective technology for the realization of stretchable systems by common printed circuit board techniques like lamination, lithography, etching and micro via technology with polyurethane as a stretchable matrix/substrate material. Mastering of the adhesion between materials and the transitions region from stretchable to non-stretchable parts of the system are crucial for the mechanical performance and robustness. Technical approaches and the obtained results to tackle these issues will be presented. After a complete embedding of the components/interconnections the systems can be firmly attached to textile or non-woven cloth, which can be subsequently integrated into garments. The described process technology bears the potential for large scale roll to roll processing. Reliability aspects for stretchable electronic systems are so far not standardized and will be discussed briefly. Electrical and mechanical functionality of test vehicles subjected to multiple stretch and mild washing cycles will be presented. A functional electronic demonstrator with embedded passives, a micro controller, and LEDs which was realized with this technology will be shown.