Top Emission---Efficient Use of Organic Electroluminescent Light
With OLED panels, there are two methods of utilizing light produced by the organic layer---top emission and bottom emission. In bottom emission, which has a comparatively simpler manufacturing process, the structure causes light, generated by the organic material, to travel downward toward the TFT. However, the presence of opaque pixel driver circuits partially block and therefore limit the amount of light, reducing brightness. Therefore, this method is comparatively inefficient in terms of utilizing light. By contrast, with top emission (the method used by Sony), the structure causes light to travel to the "top" side where there are no pixel circuits to limit the light. This is a much more efficient means of utilizing the light produced by the organic material and this method offers lower power consumption and longer life.