73‐3: A Study on WAD Improvement of a large size AMOLED panel

In this work, the WAD Characteristics were improved by forming a concave‐convex scattering structure on the organic planarization layer of large size AMOLED backplane TFT. By using a slit mask of the scanner as a VIA mask on the photosensitive poly‐imide organic planarization film, a semi‐transmissive area and a contact hole were made simultaneously without adding a separate photo process to form a concave‐convex scattering structure. On top of that, ITO/Ag/ITO anode pixel, EL and cathode layers were sequentially formed to improve WAD Characteristics of the top emitting AMOLED panel. Confirming the effect of WAD improvement and reduction of frontal luminance when forming a concave‐convex structure from the existing EL Spectrum through simulation, angle of concave‐convex structure is 10~15° to satisfy the conditions of 30% improvement in WAD, 5% drop in frontal luminance, 40‐50% of Concave‐convex structure area ratio in the planarization film was derived. As a result of fabricating a large size AMOLED top emitting panel, when Concave‐convex scattering angle of 5 ~ 12° is formed, WAD 10~24% improvement and frontal luminance drop within 5% can be seen. it was possible to confirm uniformly improved WAD value within Δu'v' 0.014 ~ 0.018 at the center/edge 9 Points compared to the normal panel.