OSRAM Opto Semiconductors announced it has developed new transparent OLED prototypes which are only a few hundred micrometers thick and do not need separate encapsulation. The samples have a luminous area of 210 cm² and are already showing the enormous potential of OLED light sources.

 
When it is switched off the OLED light source is barely noticeable. When it is switched on it produces an even light with high luminance over its entire surface.

The test samples were developed as part of the TOPAS research project funded by the Germany Ministry for Education and Research (BMBF). The aim of the project is to produce 1 m² large transparent OLED modules and will run until 2011.

Though the 17 x 17 cm² modules will have to be made larger they already have many of the properties that distinguish OLEDs from other light sources. They are extremely slim and no longer need expensive encapsulation. Their thickness is now defined only by the substrate as the carrier material – at present this is between 300 and 700 µm.

“Transparent OLEDs and flexible OLEDs at a later date will add an entirely new aesthetic dimension to lighting solutions”, said Dr. Karsten Heuser, head of the OLED division at OSRAM Opto Semiconductors. “The possibilities range from light sources that can be integrated in room dividers and furniture, for example, to entire windows that would allow natural light in during the day and flood the room with light at night.”

The OLED panels can be made transparent without any detracting structures. This is thanks to new developments in electrode design, a special component architecture and a new approach to thin-film technology. Without any additional conductor path structures on the light-emitting surface, the current is distributed evenly over the active surface, which in turn leads to uniform luminance. The new technology also simplifies the manufacturing process. The next stage is to integrate the processes into a stable manufacturing operation.

Current OLEDs are being showcased at PLDC (Professional Lighting Design Convention) from October 29 to 31, 2009 in Berlin to demonstrate the latest state of development.