Apple has filed a patent for a system that would help a mobile device such an iPhone detect an impending drop and “protect” itself with a shock mount, or in one use case, retractable glass. The patent is fairly in-depth, but portions of it pertain to a more robust glass or glass-like construct made out of sodalime or borosilicate.
One of the more interesting aspects of the patent filing is a system of sensors that are able to vibrate at frequencies that would dampen the shock from the impact of a hard surface. The idea is to distribute the shock evenly throughout the surface of an object to prevent glass from cracking. Further chemical applications could strengthen the glass even more.
While there is no guarantee the patent will be implemented into a device, it does a lot to address the main concern of the iPhone 4′s design: its glass front and back.
Source: Patently Apple