Impact testing of screen protectors for mobile devices

The mechanical damage resistance of phone components, particularly screens, is crucial for ensuring the longevity and functionality of modern smartphones. This study investigates the impact resistance of screen protector materials consisting of chemically strengthened glass and thermoplastic polyurethane (TPU) using a developed punch drop test method. The screen protectors were applied to ultra-thin glass (UTG) samples, serving as surrogates for phone screens. The impact resistance was assessed by measuring the average fracture drop height of UTG breakage beneath a screen protector for various punch tip diameters. This outcome was summarized in a parameter termed ?protectability?. The results indicate that glass screen protectors exhibit superior protection against sharp impacts due to their high stiffness, while the plastic screen protectors provide comparable protection against blunt impacts. Finite element simulations of glass and TPU screen protectors corroborate the experimental findings, highlighting the importance of material stiffness and thickness in enhancing protectability.