Optimization of screen printing processes for OLED substrate patterning

The current standard for OLED substrate patterning is photolithography [1, 2]. This relatively expensive method allows very little structural resolution, but this is not necessary for OLED lighting [3]. One way to reduce the production cost of OLED substrates are alternative patterning methods, such as laser ablation and screen printing processes developed by Fraunhofer COMEDD [4]. This paper focuses onto the optimization and further development of these substrate patterning technologies on glasses and polymer films in sheet-to-sheet processes. For this, alternatives to the currently used printing pastes are examined in order to eliminate problems with residues of the printing paste at the active area, solvent residues and the large roughness of the printed layers. The goal of this optimization is a significant improvement of the substrate quality for subsequent deposition technology and a corresponding increase in the yield of flawless OLEDs.