Fraunhofer FEP's COMEDD developed new color-tunable transparent OLED lighting panels. These panels were presented at the LOPE-C exhibition last week, and they looked very nice.
According to the Fraunhofer color tunability is the most wanted feature (after flexibility) by lighting designers. The Fraunhofer uses a stacked approach (unlike Pioneer's stripe-pattered RGB-OLEDs, for example). A stacked approach enabled the Fraunhofer to make the panels both color-tunable and transparent - in any shape.
The current panels use blue and yellow OLED emitters on on top of the other. They say that a drawback of this technology is that it limits the size of the OLED - currently at about 80 mm diameter (due to the many transparent electrodes incorporated in the device).