Printing of light emitting devices on textiles was the subject of a masterclass held by ESMA on 23rd June 2015 in Düsseldorf where German and Belgian researchers presented the results of a collaborative research project.
by Marianne Curtis, World Textile Information Network
The research, introduced by Prof. Wim Deferme of Hasselt University, Belgium, looked at three main technologies – preparation of textile and/or conductive coatings; ink formulation and printing of light emitting diodes (LEDs); and encapsulation of applications/devices.
For wearable textiles organic LEDs (OLEDs) were used. High barrier properties are required and carbon nanotubes were used to coat the textiles to maintain flexibility. For non-wearable textiles e.g. lamp shades and wallpaper, electroluminescence (EL) can be used. Less strong barrier properties are necessary and conductive yarns e.g. silver, are appropriate.
Recent developments in LEDs permit them to be used in environmental and task lighting. Advantages over incandescent light sources include lower energy consumption, longer lifetime, improved physical robustness, smaller size and faster switching. LEDs are finding applications in e.g. aviation lighting, automotive headlamps, advertising, general lighting, traffic signals and camera flashes. However, LEDs powerful enough for room lighting are still relatively expensive and require more precise current and heat management than compact fluorescent lamp sources of comparable output. Textiles provide a flexible medium for such applications.