A key substrate material supporting the development of foldable and rollable display technologies. Invar alloy (Fe-36Ni), with its low coefficient of thermal expansion, helps minimize dimensional changes during high-temperature OLED evaporation, encapsulation, and lamination processes, contributing to pixel alignment accuracy and production yield. The strip (approximately 0.02–0.05 mm thick) also offers good surface flatness, low magnetic hysteresis loss, and favorable etchability. It can be used as fine metal mask (FMM), support layer, or heat dissipation substrate for flexible AMOLED panels, playing a significant role in screen bending lifespan and display uniformity, and is an important material in the flexible display supply chain.