Failure Analysis of Polarizer of Liquid Crystal Display

The polarizer film is an important component in the Thin-film-transistor liquid crystal displays (TFT-LCDs), which is a multilayer composite film developed by using dichromatic material stretching film technology. However, the polarizer film is liable to fail in hygrothermal circumstances. In this work, we analyzed a polarizer film shipped from China to Brazil that failed due to the ocean environment. By analyzing the structure, composition, and crystallinity of the polarizer film, Polyvinyl Alcohol (PVA) layer of the polarizer film has larger crystallinity, and there are bonding pores between the PVA layer and the Triacetyl Cellulose (TAC) layer. Under the action of the marine environment, the I-3(-) ions in the PVA layer were released, resulting in the separation of PVA layer and TAC layer at the bonding pores, and then forming bright spots. Furthermore, through analyzing the marine environment and simulated environmental experiments, it was determined that the thermal environmental factor induces the release of I-3(-) ions in the PVA layer. Finally, based on the failure process and failure mechanism of the polarizer, improvement measures to prevent the occurrence of bright spots of the polarizer are proposed.