29.1: Full Color Active Matrix OLED Displays with High Aperture Ratio

Abstract

For the integration of organic light emitting diodes (OLEDs) on an active matrix backplane, an efficient top‐emitting OLED is essential since the TFT‐circuitry covers a large space of the pixel aperture. Moreover, for the integration on n‐channel transistors used in amorphous silicon technology an inverted (anode on top) OLED setup is necessary. We here present a way to manufacture efficient top emitting inverted OLEDs on active matrix substrates by applying our proprietary technology of intentionally doped charge carrier transport layers. We demonstrate their integration in full color active matrix displays with QVGA and VGA resolution.

10.4: High Performance and Innovative OLED Structures and Display

“…Such an inverted structure, although not straightforward to make, has been demonstrated by J. Blochwitz-Nimoth et al 4 . There are two major challenges involved in the inversion of the OLED stack.…”

High-efficiency p-i-n organic light-emitting diodes with long lifetime

“…Efficient top-emitting OLEDs using doped 15 and undoped 12 layers have been previously demonstrated, but usually a specially prepared substrate is needed for a good performance. One of the key advantages of PIN structures is not only the possibility to produce efficient top-emitting devices, but also to invert 15,16 the stack, forming a NIP OLED. It is therefore possible to apply doped OLEDs to a very wide range of substrates, as for example active matrix on a-Si n-channel TFTs using a pre-existing backplane technology.…”

64.4: Novel Materials and Structures for Highly-Efficient, Temperature-Stable, and Long-Living AM OLED Displays

“…Due to constraints of the backplane, the overall aperture ratio of bottom emitting AM OLED displays is in the range of 35 to 40%. By changing to a top emitting architecture the aperture ratio can be doubled since opaque TFTs, lines and capacitors do not longer decrease the active pixel area [1]. Thanks to their higher aperture ratio, top emission pixels need to be driven less bright.…”