Crafting interior holes on chemically strengthened thin glass based on ultrafast laser ablation and thermo-shock crack propagations

To prevent glass cracking from external mechanical damages, chemically strengthened glass is usually employed. The cutting of strengthened glass becomes critical due to their residual tensile stress induced in the inner core of glass attributed to the ion exchange process. This paper describes a novel technique for dealing cutting interior holes and separation of strengthened ultrathin glass for the display unit of mobile communication and computational devices. This method integrates picosecond laser ablation with quenching induced thermo-shock for accomplishing such a task. Essential analyses are performed based on fracture mechanics and finite element method to provide the scientific basis of such an approach. Experimental results indicate that with a proper temperature control, the proposed method could achieve successful separations for various enclosed shapes with the associated surface roughness satisfying the requirement.