Osram Claims Warm White Organic LED Breakthrough
Organic light emitting diodes (OLEDs) are very promising. They are more
expensive efficient than incandescents without the downsides of CFLs (fragility, mercury), and they have the potential to become less expensive than regular LEDs. Because of their thinness and flexibility, they could be used in all kinds of places (a designer's dream).
We're not quite there yet, but things are moving fast. In late 2005, Osram was announcing "a breakthrough in polymer-OLED technology by achieving a record 25 lumens-per-watt (lm/W) of device efficiency". Now, they are announcing that they manufactured warm white OLEDs with an efficiency of 46 lm/W and a life of more than 5000 hours at a brightness of 1000 cd/m2. That's close to the efficiency of fluorescent lamps, and more than twice that of incandescent lamps.
The color rendering index (CRI) of the almost 100 cm² large prototype is 80.
For comparison, an incandescent lightbulb has a CRI of 100 (the benchmark), and most fluorescent score between 50 and 90 (most on the low end).
OLEDs degrade rapidly in the presence of oxygen and water vapour. Heuser said the firm is using an undisclosed encapsulation process to block these - leading to the 5,000 hour life to half brightness.
For ease of manufacture, installation, and robustness flexible emitters are desirable, but the whole OLED industry is still looking for effective vapour-blocking barrier layers.
::OSRAM achieves high levels of efficiency and lifetime, ::Osram hits 46 lm/W in OLED lighting tile