Flexible ultra‐thin glass with low Young's modulus for foldable display

Abstract Novel applications in the foldable electronics market require flexible substrates, notably ultra‐thin glass (UTG). While conventional UTG is known for its high robustness and resilience, its brittle characteristics commonly lead to cracks, breakages and other field failures. This study introduces super‐flexible and ion‐exchangeable glass for foldable displays, achieved by lowering the Young's modulus of the glass. Effective reduction of Young's modulus from 72 to 53 GPa was achieved when SiO 2 was substituted with B 2 O 3 and P 2 O 5 . Indentation and two‐point bending tests examined the bending characteristic of the glasses. The obtained low modulus glasses showed enhanced flexibility, including a high level of fracture toughness and resistance to flaw formation as well as decreased bending repulsive force, implying smaller folding radius. The enhanced flexibility of the glass, which makes it suitable for various foldable devices, was discussed based on structural changes induced by composition.