P-182: Analysis of Bright Lines in Passive-Matrix OLEDs using High-Speed Photography

Abstract

Horizontal bright lines are analyzed using high-speed photography. Although the shutter speed is set to the scan period, multiple scan buslines emit light. This is because the scan voltage is simultaneously applied to the multiple scan buslines. Therefore, the horizontal lines seem to be caused by short circuits between neighboring cathode electrodes, which are simultaneously used for the scan buslines. Vertical bright lines are also analyzed using high-speed photography. The vertical lines emit light when the corresponding scan buslines are selected. This is because the signal voltage applied to the vertical lines becomes higher. Therefore, the vertical lines seem to be caused by short circuits between anode electrodes and cathode electrodes in OLED pixels. Although the occurrence mechanisms of the horizontal lines and vertical lines may be different for each panel, it is found that the high-speed photography is a useful and interesting to analyze defects in passive-matrix OLEDs.