P‐103: Non‐Destructive FMM Shadow‐Level Evaluation with Fluorescence Lifetime Imaging Microscopy

When OLED materials are depositing on the back‐plane in the evaporation process, they can be mixed in pixels by the FMM shadow. As a result, the luminance is decreased and abnormal display panels are made. Previously, we measured the level of shadow using AFM (atomic force microscopy) technique, but this technique cannot be applied to actual display panel. So we have introduced the FLIM (fluorescence lifetime imaging microscopy) technique to identify the cause of the problem. We can analyze the mixed OLED materials using the lifetime of organic materials at a specific wavelength. Finally, we can define the level of shadow and distinguish the normal and abnormal pixels while the general PL (photoluminescence) method cannot measure the shadow. Therefore, this technique is very useful to confirm the shadow level with non‐destructive and high‐resolution imaging.