Mr. Tian Yuansheng from Organic EL Lighting gave a speech on “OLEDs World Summit 2012”, he said that: in theory, the luminous efficiency of organic EL is the same as that of LED lighting technology. However, organic EL lighting applications have much higher efficiency, which can improve the luminous efficiency of the entire organic EL lighting products to 249lm/W, which is no doubt the highest luminous efficiency lighting technology in the world presently.
According to his introduction, the theoretical boundary value of luminous efficiency of white organic EL components is around 249lm/W at 4000K (single light-emitting construction), and 184lm/W for series construction. The theoretical boundary value is a laboratory data that based on the assumption of 100% light-extraction efficiency and 100% external quantum efficiency. The luminous efficiency of white-ray LED lighting components is around 260lm/W. If using single light-emitting construction, organic EL lighting applications can have a similar luminous efficiency as white-ray LED does. Organic EL is also named as organic LED, OLED. They have much similar light-emitting principles as LED. From this point, there is no doubt that these two technologies have much closed luminous efficiency.
Among all organic EL components that produced, some of them are closed to 100% in internal quantum efficiency, but with a light efficiency only 60%.
In the comparisons between LED and organic EL, Mr. Tian Yuansheng indicated that: “Even using the current organic EL technology, the luminous efficiency of the lighting equipment can reach the level of LED lighting applications. According to ‘DOE Multiyear Plan’ a technical report for LED technology issued in March, 2010 by Department of Energy (DOE), before 2009 the luminous efficiency of LED lighting products is only 32.3% that of led tunnel light sources.” This is quite normal, since exposed light sources will cause damages to human eyes. That is the reason why most LED lighting products are covered by frosted covers. Diffusion plates and other protective shells will reduce the luminous efficiency inevitably. However, in most cases, organic EL components can be directly used as lamp in organic EL lighting applications without any protective covers. Thus, usually the luminous efficiency of organic EL lamps is quite closed to commonly used LED lamps.