Chemical Strengthening of Ultra-Thin Glass for Use as Cover Window of Flexible Displays

The recent commercial success of foldable smartphones is indebted in part to integration of ultra-thin glass (UTG) into the flexible display modules. To endow glass with such a foldability, while keeping its merits over polymeric materials, tons of complicated issues need to be resolved in addition to thickness reduction. Since UTG is subjected to repeated deformations during its service as a flexible cover window, extra care is required to minimize microcracks during the whole preparation process. Here, it is noteworthy that chemical strengthening via ion exchange should be performed to UTG for better durability. In this article, after briefly reviewing the current status of UTG in terms of production and process, its chemical strengthening is highlighted as a viable option to further innovate its functionalities. A new ion-exchange technique which is not adopting the molten-salt-bath is proposed, and some experimental demonstrations exemplifying the concept of ‘actively stress-managed glass’ are delineated.