Intelligent
textiles
Intelligent
textiles, variously known as smart fabrics, electronic textiles, or e-textiles, have attracted
considerable attentions worldwide due to their potential to bring revolutionary
impacts on human life. Despite many promising progresses in this
exciting newly emerged research field, there still exist a number of important
obstacles. One of the most
challenging issues is the conflict between the flexibility of the textiles and
the need to incorporate sensing and computation modules. To address this critical issue, an
innovative intelligent textile technology is proposed. The central
hypothesis is that practical intelligent textiles can be realized by integrating
fabrics with flexible transducers/electronics that are made using a unique,
¡®flexible-skin¡¯ technology.
The unique features of the silicon-based
flexible skins are extremely desirable for intelligent textiles. A novel approach of making intelligent
textiles by integrating the silicon-based flexible skins with textiles is
proposed. The most important
advantage of this novel technology is its compatibility with current MEMS and
IC technologies, since MEMS devices (micromachined transducers) and ICs can be
fabricated on the silicon wafer before the formation of the skin. This not only saves significant R&D
efforts by avoiding re-invention, but also enables the integration of abundant
sensing and computational capabilities offered by the silicon-based technology.
Figure 1. Top and cross section
views of the proposed flexible skin to be woven into textiles.
In order to be integrated with textiles, the original flexible skins
are modified and a new perforated structure is proposed as schematically shown
in Fig. 1. The new flexible skin
consists of 4 components: (1) silicon islands that host sensors, electronics,
and bonding pads; (2) metal interconnect wires between silicon islands; (3)
polymer layers that sandwich silicon islands and metal wires; and (4) stitching
holes etched through polymer layers, which allow the direct sewing into
fabrics. One of the fabricated
silicon flexible skins is shown in Fig. 2 (a). It can be easily twisted and bent
without breaking the interconnect traces and silicon islands as shown in Fig 2
(b)
(a) (b)
Figure 2. (a) A silicon flexible skin with stitching holes; (b) a folded silicon flexible skin.
The flexible transducers/circuits made by the proposed method can be
directly embroidered into textiles.
It is worth noting that the stitching methods and patterns have
substantial impact on the mechanical properties and robustness of the assembled
fabrics. Numerous stitching
patterns and methods, which have already been developed in the textile
industry, will be an excellent resource to exploit. The following picture shows
one skin stitched onto the surface of textiles using conductive yarns. The electrical contact was made by
conductive epoxy.
Figure 3. A silicon flexible skin stitched onto the surface of a piece of KEVLARÒ fabric.
To study the mechanical properties of the assembled intelligent textiles, diffused silicon strain gauges were integrated on silicon islands as shown in the following picture. These strain gauges enable in-situ measurement of the strains experienced by the silicon islands during stretching, twisting, or bending.
Figure 4. Flexible skin with integrated strain gauges
Funding:
This research is supported by NSF Grant
ECS-0501314.
References:
¡¤
R. B. Katragadda
and Y. Xu, ¡°A Novel Intelligent
Textile Technology Based on Silicon Flexible Skins¡±, Proceeding of the
International symposium on wearable computer 2005 (ISWC05),
Some links about intelligent textiles:
Georgia Tech Wearable Motherboard