OLEDs for practical consumer application.
The "100" in the group's name points to the minimum target specifications:
100 lumens per Watt;
100 thousand hours useful lifetime;
1 meter square devices (100 cm by 100 cm);
100 Euros or less per square meter in production costs.
When most people think of OLEDs, they think of the applications that get all the press: pixilated full-color displays now found in cell phones and starting to appear as larger panels for televisions. Yet this type of color display may turn out to be just the tip of the iceberg for the OLED industry in the near term.
With some estimates claiming that lighting accounts for almost 20 percent of the worldwide energy consumption, the search for more efficient alternatives is gaming momentum. Incandescent bulbs are inefficient at about 15 lumens per Watt. Fluorescent tubes are the efficiency champions at about 90 lumens per Watt, but they generally use mercury which creates a hazardous waste disposal problem. White OLEDs are one of the brightest prospects for a lighting replacement that could be commercially viable as soon as next year. If the OLED 100.EU group is successful, the results eventually could cut worldwide energy demand by as much as 10 percent or more.
The research program is projected to cost nearly 20 million Euros over its three years lifespan, with 12.5 million Euros in funding coming from the European Union. The program is looking to improve all aspects of the solid state lighting technology, from substrates to the emissive materials.
This new program will stand on the shoulders of the previous OLLA project. The goal of that effort was to produce OLED lighting with 50 lumens per Watt efficiency with 10,000 hours lifetime. Development focused on the use of Novaled AG's PIN OLED technology. These are small molecule OLED materials that rely on doping of the hole and electron transport layers to increase efficiency while lowering the operating voltages and improving manufacturing yields.
Some of the new group's goals are clearly within reach. For example, researchers from University of Michigan and Princeton University have demonstrated 70 lumens per Watt from a novel white OLED design that includes a microlens layer to concentrate the light output (as reported in the August issue of Nature Photonics). This is 40 percent better than the OLLA result, and nearly five times better than the typical incandescent bulb. It also approaches the fluorescent lamp efficiency, but without the hazardous waste problems.
One of the biggest challenges for the OLED100.eu group is to make the technology advances practical, which means that these gains have to come off the production line and not just out of some test tube conditions in a lab.
The major participants in OLED 100.eu include Philips, OSRAM, Siemens, Novaled and Franhofer IPMS, all of which were among the 24 organizations that were involved in the OLLA project.
In addition to the technology advances and potential environmental benefits, this research is noteworthy for a third reason. It's easy to think that most of the display innovation is coming from North America and Asian countries, but remember that a lot of important original research is going on in Europe. OLED100. EU is a high-profile example of the kind of work underway on that "other" continent there that can have a major impact on lighting and display applications worldwide.
by Alfred Poor, Contributing Editor
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|Title Annotation:||ON THE LIGHT SIDE|
|Publication:||ECN-Electronic Component News|
|Date:||Sep 1, 2008|
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