Researchers from Holst Centre (set up by TNO and imec), imec and CMST, imec’s associated lab at Ghent University, have demonstrated the world’s first stretchable and conformable thin-film transistor (TFT) driven LED display laminated into textiles. This paves the way to wearable displays in clothing providing users with feedback.
Wearable devices such as healthcare monitors and activity trackers are now a part of everyday life for many people. Today’s wearables are separate devices that users must remember to wear. The next step forward will be to integrate these devices into our clothing. Doing so will make wearable devices less obtrusive and more comfortable, encouraging people to use them more regularly and, hence, increasing the quality of data collected. A key step towards realizing wearable devices in clothing is creating displays that can be integrated into textiles to allow interaction with the wearer.
“Wearable devices allow people to monitor their fitness and health so they can live full and active lives for longer. But to maximize the benefits wearables can offer, they need to be able to provide feedback on what users are doing as well as measuring it. By combining imec’s patented stretch technology with our expertise in active-matrix backplanes and integrating electronics into fabrics, we’ve taken a giant step towards that possibility,” says Edsger Smits, Senior research scientist at Holst Centre.
The conformable display is very thin and mechanically stretchable. A fine-grain version of the proven meander interconnect technology was developed by the CMST lab at Ghent University and Holst Centre to link standard (rigid) LEDs into a flexible and stretchable display. The LED displays are fabricated on a polyimide substrate and encapsulated in rubber, allowing the displays to be laminated in to textiles that can be washed. Importantly, the technology uses fabrication steps that are known to the manufacturing industry, enabling rapid industrialization.
Following an initial demonstration at the Society for Information Display’s Display Week in San Jose, USA earlier this year, Holst Centre has presented the next generation of the display at the International Meeting on Information Display (IMID) in Daegu, Korea, 18-21 August 2015. Smaller LEDs are now mounted on an amorphous indium-gallium-zinc oxide (a-IGZO) TFT backplane that employs a two-transistor and one capacitor (2T-1C) pixel engine to drive the LEDs. These second-generation displays offer higher pitch and increased, average brightness. The presentation will feature a 32×32 pixel demonstrator with a resolution of 13 pixels per inch (ppi) and average brightness above 200 candelas per square meter (cd/m2). Work is ongoing to further industrialize this technology.
For further background information:
9.4: Stretchable 45 × 80 RGB LED Display Using Meander Wiring Technology, Ohmae et al. SID 2015, June 2015
1.2: Rollable, Foldable and Stretchable Displays, Gelinck et al. IMID, Aug. 2015.
13.4 A conformable Active Matrix LED Display, Tripathi et al. IMID, Aug. 2015
About Holst Centre
Holst Centre is an independent R&D center that develops technologies for flexible electronics, wearable health solutions and perceptive systems for the intuitive internet of things, in an open innovation setting as well as in dedicated research trajectories. A key feature of Holst Centre is its partnership model with industry and academia based around roadmaps and programs. It is this kind of cross-fertilization that enables Holst Centre to tune its scientific strategy to industrial needs.
Holst Centre’s fundamentals are to contribute to answering global societal challenges in healthcare, lifestyle and sustainability. This is visible through the motivation of its researchers, its different collaboration models and the choice of its research topics.
Holst Centre was set up in 2005 by imec (Flanders, Belgium) and TNO (The Netherlands) and is supported by local, regional and national governments. Located on High Tech Campus Eindhoven, Holst Centre benefits from, and contributes to, the state-of-the-art on-site facilities. Holst Centre has over 200 employees from some 28 nations and a commitment from more than 40 industrial partners.
Imec performs world-leading research in nanoelectronics. Imec leverages its scientific knowledge with the innovative power of its global partnerships in ICT, healthcare and energy. Imec delivers industry-relevant technology solutions. In a unique high-tech environment, its international top talent is committed to providing the building blocks for a better life in a sustainable society. Imec is headquartered in Leuven, Belgium, and has offices in Belgium, the Netherlands, Taiwan, USA, China, India and Japan. Its staff of about 2,200 people includes almost 700 industrial residents and guest researchers. In 2014, imec’s revenue (P&L) totaled 363 million euro. Further information on imec can be found at www.imec.be. Stay up to date about what’s happening at imec with the monthly imec magazine, available for tablets and smartphones (as an app for iOS and Android), or via the website www.imec.be/imecmagazine
Imec is a registered trademark for the activities of IMEC International (a legal entity set up under Belgian law as a “stichting van openbaar nut”), imec Belgium (IMEC vzw supported by the Flemish Government), imec the Netherlands (Stichting IMEC Nederland, part of Holst Centre which is supported by the Dutch Government), imec Taiwan (IMEC Taiwan Co.)and imec China (IMEC Microelectronics (Shanghai) Co. Ltd.) and imec India (Imec India Private Limited).
The Centre for Microsystems Technology (CMST) is an imec associated laboratory at the University of Ghent. CMST has about 55 employees, the vast majority having a university degree. CMST is a centre for smart micro-systems integration focusing on design as well as on technology development research in six domains: High-density interconnection, including 3D component stacking and assembly; Large-area electronics, including flexible and stretchable electronics; Polymer Structuring and Microfluidics, including sensor and electronics integration; Optical interconnects and sensors, including flexible waveguides; Display systems, including LCoS micro displays and LEDs; Smart-power ASIC design, including TCAD-based high-voltage device development. Imec-CMST has a state-of-the-art cleanroom of 770 m2, housing all necessary equipment and tools to perform its research in the aforementioned domains: thin-film and thick-film deposition and patterning equipment, large area and stretchable circuit fabrication and assembly equipment, laser ablation and structuring equipment, test and inspection equipment, etc. CMST plans and executes collaborative projects with numerous Flemish and international academic and industrial partners.
The 3800 TNO professionals put their knowledge and experience to work in creating smart solutions to complex issues. These innovations help to sustainably strengthen industrial competitiveness and social wellbeing. We are partnered by some 3000 companies and organisations, including SMEs, in the Netherlands and around the world. On the topic of Healthy Living we initiate technological and societal innovation for healthy living and a dynamic society.
For more information about TNO and the seven societal themes that are the focus of our work, go to www.tno.nl.
On the topic of Industrial Innovation we reinforce the innovative strength of industry through innovation in products and processes, with a strong focus on sustainability.