Researchers in the UK have developed battery-powered textile yarns that can be used to make clothing glow in the dark without a reflective light source.

The electroluminescent (EL) yarns, invented by The University of Manchester's William Lee Innovation Centre (WLIC), have the potential to be incorporated into clothing worn by cyclists, joggers and pedestrians.

The yarn consists of an inner conductive core, coated with electroluminescent ink that emits light when an electric current is passed through it. A protective transparent encapsulation, with an outer conductive yarn is wrapped around it.

When the EL yarn is powered, the 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.

Dr Tilak Dias, head of the WLIC, 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."

Current high visibility products such as those used by emergency services depend on external light sources to make them visible, while the EL yarns can be seen in dark places.

By Monica Dobie.