A team of Korean engineers have developed wearable displays Integrating OLEDs (organic light-emitting diodes) for various applications including fashion, IT, and healthcare.
Professor Kyung Cheol Choi at the KAIST (Korea Advanced Institute of Science and Technology) School of Electrical Engineering said the research for realising displays on clothing gained considerable attention from academia as well as industry when research on luminescence formed in fabrics was introduced in 2011; however, there was no technology for commercialising it due to its surface roughness and flexibility.
His team used two different approaches, fabric-type and fibre-type, in order to realise clothing-shaped wearable displays. In 2015, they successfully laminated a thin planarisation sheet thermally onto fabric to form a surface that is compatible with the OLEDs approximately 200 hundred nanometers thick. They then introduced a dip-coating method, capable of uniformly depositing layers, to develop polymer light-emitting diodes, which show high luminance even on thin fabric. Now they have made fabric-based OLEDs, showing high luminance and efficiency while maintaining the flexibility of the fabric. Their wearable device facilitates the operation of OLEDs even at a bending radius of 2mm.
“Having wavy structures and empty spaces, fibre plays a significant role in lowering the mechanical stress on the OLEDs,” said Choi, adding that screens displayed on daily clothing is no longer a future technology.
"Light-emitting clothes will have considerable influence on not only the e-textile industry but also the automobile and healthcare industries,” he said
“It means a lot to realise clothing-shaped OLEDs that have the world’s best luminance and efficiency. It is the most flexible fabric-based light-emitting device among those reported. Moreover, noting that this research carried out an in-depth analysis of the mechanical characteristics of the clothing-spared, light-emitting device, the research performance will become a guideline for developing the fabric-based electronics industry.”
[OLEDs operating in fabrics. Photo: KAIST]