Knitting specialists at the University of Manchester have developed high-tech battery-powered textile yarns that could be used to make clothing glow in the dark. These yarns could soon be integrated into clothing worn by cyclists, joggers, outdoor workers and pedestrians. These garments would be safer for users than current clothing used by emergency services which need external light sources to make them visible.
You can see on the left a EL yarn garment worn by a dummy close to a blurred person (Photo: Ed Swinden, for the University of Manchester). Here is a link to a larger version of this picture. This EL yarn has been developed at The William Lee Innovation Centre (WLIC) by a team led by Dr Tilak Dias, Head of WLIC and Senior Lecturer in Knitting, for the Intelligent Health Garment project. Dias is also one of the founders of Engineered Fibre Structures Ltd, a University of Manchester spin-out company established in 2001 and which "specializes in providing textile solutions for medical, healthcare, sportswear, personal protective equipment, industrial, engineering, aerospace, automotive and other technical applications."
So what is the real innovation behind this EL yarn? "EL yarn is a novel technology, which emits light when powered by a battery. Its development has been based on thin film electroluminescent technology. The yarn consists of an inner conductive core yarn, coated with electroluminescent ink -- which means it emits light when an electric current is passed through it -- and a protective transparent encapsulation, with an outer conductive yarn wrapped around it.
And how does this work? "When the EL yarn is powered with an inverter the resultant electrical field between the inner and outer conductor causes the electroluminescent coating to emit light. The emission of light occurs between the contact points between the outer yarn and the inner yarn."
So when will we see roadside workers equipped with this kide of glowing garments? Dias recognizes that there are still some problems associated with the flexibility of the garments, and said: "At the moment the EL yarn we have developed is less flexible than conventional yarns. But it is more flexible than current optical fibres that are incorporated within fabrics to provide illumination."
Over the mountains of the moon, down the valley of the shadow. Ride, boldly ride, the shade replied, in search of el Dorado.
—Leigh Brackett (1915–1978)
For more images of the EL yarn-based prototype garments, you can visit this WLIC page (links to images at the bottom).
Sources: University of Manchester, via EurekAlert!, October 26, 2007; and various websites
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