Apple has patented a way to make its sapphire screens even tougher

The U.S. Patent and Trademark Office on Thursday published an Apple patent describing a method of implanting ions in a sapphire display structure, strengthening the already hard material without using chemical treatments. As noted in Apple’s “Sapphire property modification through ion implantation” patent filing, traditional chemical strengthening techniques used on glass screens may not be effective when applied to other materials such as sapphire. Thus, Apple proposes a new hardening method of impregnating the crystalline lattice structure of corundum, of which sapphire is a variety, with ions to create a compressive stress layer that enhances stability. The invention points out that when a sapphire structure fails or breaks, it’s usually the result of propagations of surface flaws when the component is put under stress. To prevent against cracks during a drop event, Apple’s ion implantation method embeds ions within the sapphire substrate, either between existing crystal lattice sites or naturally occurring voids. In one embodiment, ions may be embedded so as to form an amorphous, or non-crystalline, section within the sapphire substructure.