Study on Factors Affecting Black Matrix Charging of Positive Gamma LCD Products in High Humidity Operating Conditions

In this paper, we researched the abnormal greenish display of 33.8-inch liquid crystal display (LCD) in the high-humidity conditions. By applying voltage to the BM, it is found that the black matrix (BM) is negatively charged when the panel is green, and then the panels are exposed to different environmental conditions to study the effects of temperature and humidity. The results show that the accumulation of negative charge needs both high humidity and electric field, and the charge comes from the edge of the Panel. The scanning electron microscopy (SEM) analysis of the edge around the panel indicates that the charge is accumulated by passing through the over coat (OC) layer, the charge blocking effect of the thin OC film layer significantly reduced in high-humidity operating conditions. Therefore, the accumulation of charge in the BM effectively decreased by increasing the distance of the Sealant wrapped BM or the distance from BM in active area to the edge of panel.