ROLLED project makes flexible light sources a reality
The EU-funded project ROLLED has succeeded in developing a flexible OLED (organic light emitting diode) light source that could make packaging more attractive, among other applications. The use of roll-to-roll printing technology makes it possible to mass produce the flexible OLED element, the project partners said. ROLLED was funded EUR 2.25 million under the 'Information society technologies' Thematic area of the EU's Sixth Framework Programme (FP6). Coordinated by the VTT Technical Research Centre in Finland, ROLLED's objective was to develop a cheaper, volume-scale, roll-to-roll manufacturing technology for the production of flexible organic light emitting diodes (OLEDs) with pixels of arbitrary sizes and shapes, the researchers said. The project partners explained that this latest method is more economical when compared with the conventional production method. This is because the cost of purchasing the equipment to produce the organic light emitting diodes is lower, while the production speed is higher than that of the conventional method. Each OLED element costs only tens of cents to produce. Researchers are currently evaluating other applications to cut the price even further. By using the element in a number of goods and in different locations, including supermarket shelves and posters, consumers will be drawn to the products, the researchers said. Added bonuses are that the elements can be used to thwart product copying efforts and be connected to sensors with the capacity to measure the freshness of packaged foods. The innovative light sources are similar to LED lights. However, OLED elements consume little power and because they are manufactured with organic materials, they can be produced with printing methods on large, flexible surfaces. This type of production makes them especially suitable for packaging. The element is encapsulated in a moisture barrier film, and has a thickness of 200-250 micrometres, which is equivalent to 3 or 4 sheets of paper, the team said. Project partners included the Swiss Centre for Electronics and Microtechnology, the Leibniz Institute for New Materials in Germany, PolylC (a German company specialising in printed electronics) and UPM (a Finnish company involved in the forest industry). The Swiss group was responsible for developing various patterning technologies and the Leibniz Institute focused on establishing anode inks and barriers. Besides developing the printing process, the Finnish Technical Research Centre set up a low work function cathode ink that improves the performance of the components by reducing power consumption and decreasing the power supply voltage. The elements can be used in all electronics components that are fit for print, such as solar cells and transistors. The researchers tried the production method in two demonstration tests. The first test was presented as a two-colour OLED element connected to a product package. A green tick is shown when the package is closed. Once the package is opened, the fuse is blown and the tick becomes a red cross. The second test indicated that a near field communication (NFC) telephone could power up the OLED element. The researchers used a business card printed with the EU flag whose stars, which were equipped with the elements, lit up when an NFC phone was placed near the card. According to VTT's Technology Manager, Arto Maaninen, the first OLED elements will be launched on the market within two years.
Countries
Germany, Finland