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2.3.3 Applications in the clothing sector
2.3.3.1 Research projects and products
Optical fibres are currently used in textile structures for different application areas, such as
telecommunication, illumination, medical products and sensor technology.
At the AVANTEX 2002, a research team from Georgia Tech presented a smart shirt, called the
Georgia Tech Wearable Motherboard that makes use of optical fibres to locate the exact position of a
bullet’s impact. The Wearable Motherboard TM is probably the first intelligent suit that can be used for
medical purposes. The basic shirt includes an optical wiring structure that can be equipped with
conventional sensors to measure different body parameters.
Currently, optical fibres are used to create textile-based displays, so-called Optical fibre flexible
display (OFFD). For this purpose optical fibres as well as conventional fibres make up a woven fabric
structure. A small electronic device, integrated into the textile system, controls the LEDs that illuminate
groups of fibres. Each group provides light to one pixel (given area) on the matrix. A special control of
the LEDs enables various patterns to be displayed in both, dynamic and static manner. The fact that it
posses a very thin size and a ultra light weight makes the structure interesting.
In general, optical display textiles can be created on the one hand by existing or conventional textile
structures, into which optical fibres are inserted. On the other hand they can be produced by newly
developed textile materials. To the first group belong the works of the research group of Vladan
Koncar and of the research of Eric Deflin for France Telecom, as well as the products of the company
Luminex. Their projects will be described briefly in the following.
A research group around Vladan Koncar in France is working on a woven OFFD using Poly (methyl
methacrylate) (PMMA) fibres as weft threads and silk as warps. Silk was chosen to result in good
flexibility, fine titration and an improved capacity to diffuse and reflect the light emitted by the optical
fibres for better legibility of information. They also tested different finishing methods, e.g. coating, to
ensure the grid stability and flame resistance and to enable optimal light emission intensity and
contrast. The screen for fabric displays comprises a number of surface units or pixels, which are
directly formed on the optical fibres. The process consists of generating micro-perforations that reach
into the core of the fibre. The remainder of the fibre, which did not receive any specific processing,
conveys the light without being visible on the surface. Generally, two different processes can be used
to perforate the fibres, either a mechanical treatment by the projection of microparticles with different
velocities on the optical fibre’s cladding, or a chemical treatment by using different solvents. There are
three different methods to light ON and OFF static patterns on the fabric, like texts, logos and scanned
pictures. The first method uses a basic fabric. A stencil key delimits the lightening zone. The picture
remains static with a high resolution. In the second method, the zone to be lit is formed during weaving
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