48.3: Novel Fracture Resistant Glass for Mobile Display Cover

Abstract

Novel fracture resistant glass named Dragontrail TM X for mobile display cover was developed through fracture analysis of smartphones and tablet PCs. Cover glass design guideline to prevent cover glass fracture, higher compressive stress and lower central tension, was confirmed by extensive impact fracture tests. The glass was designed to achieve high compressive stress over 1000MPa at 30m in depth of layer. The glass can be manufactured by float mass production process.

Product design for strong cover glass

“…Small curvature and sharp shape of the material which strikes the glass will be prone to damage the glass. The four‐point bending (4 PB) test is generally used to evaluate this mode; however, the cylinder impact test can be also applied. In the cylinder impact test, a pendulum tester with a cemented carbide cylinder strikes the glass edge.…”

“…σ ¼ K IC = YÂc 1=2 À CT; when DOL<c; (4) where σ is the stress at the fracture, K IC is the fracture toughness of the glass, Y is the geometric parameter of the flaw tip, and c is the depth of the flaw.…”

P‐60: High Edge Strength Glass for Mobile Devices

“…The cover glass of mobile devices demands to be unbreakable, but breakage sometimes occurs in daily use. Various types of glass have been proposed [3] [4]. However, the issue of breakage of cover glass is not yet solved.…”