Fig. 1. OLED lights are flat and efficient light sources, with potential efficiencies up to 150 lumen W.
OLEDs could be used for power-efficient large area light sources
Philippe Christou, Michael Elwell and Bernhard Sailer believe that increased applications and energy efficiency mean that OLEDs will be among the next generation of general purpose lighting.
F
ollowing their discovery more than 50 years ago, organic light emitting diodes (OLEDs) have since been viewed as holding significant benefits, particularly for use in display technologies. Because OLEDs are classed as light emitters,
they do not require a backlight. This means that battery operated products with OLED fitted displays have the potential to perform better and even outlive their LCD equipped counterparts. More recently, with the EU’s objective of cutting at least 20 per cent in C02
emissions by 2020 and
studies by the JRC showing a huge potential for saving energy by creating better energy efficiency forming the backdrop, the lighting industry has gradually started to regard OLEDs as promising alternatives to conventional light sources. While solid state inorganic light emitting diodes (LEDs) comprise point light sources, OLEDs could be used for power- efficient large area light sources or general illumination with their revolutionary thin, flat, transparent, lightweight and flexible properties. OLEDs provide brighter, crisper displays than both conventional LEDs and liquid crystal displays (LCDs). They also consume up to 70 percent less energy compared to conventional light sources, meaning that OLED lighting could also help to reduce energy consumption. Hence, it’s hardly surprising that OLEDs are increasingly being seen as prime candidates for the next generation of lighting. The Fast2Light consortium, co-ordinated by Holst Centre,
brings together a group of 14 companies, research institutes and universities, with the objective of demonstrating that high quality and cost-efficient lighting foils are the future for lighting and signage applications. The project, which is partially funded under the European Union’s 7th Framework program as part of the ICT priority, is addressing large area deposition processes for fabricating cost effective, roll-to-roll light emitting OLED foils. OLEDs are sensitive to moisture and oxygen and require
protection from these in order to maintain a longer lifetime. As such, thin film barriers are one of the prerequisites for OLEDs. Having identified this, it soon became apparent to the Fast2Light consortium that measuring the properties of a barrier would be fundamental, as would standardisation of barrier materials. Within the consortium project, one of the key members,
Huntsman Advanced Materials, worked on developing a new barrier material, designed to significantly prolong the lifetime of OLEDs. The high performance, thin barrier coatings which Huntsman developed are now considered as state of the art and have recently been integrated in the world’s first flexible OLED system, on a racing car. In this year’s 24 Hours of Le Mans race, the ORECA
01 car from French racing team ORECA-Matmut used new rear view mirrors with an integrated flexible OLED on the back. The OLED itself was provided by Holst Centre. The
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