Apple loves sapphire. The iPhone 5S has a sapphire cover over the fingerprint reader and also over the camera. Recently, Apple announced a multi-year agreement with GT Advanced Technologies (GTAT) to produce sapphire on a large scale at an Apple facility in Arizona.
Under the agreement, Apple is advancing $578 million to GT and GT will employ over 700 people at Apple’s Arizona facility to manufacture sapphire. The investment, although puny compared to the cash hoard atop which Apple sits, indicates to me that Apple is doing more than contracting with GT for camera covers and quite likely moving forward to device screens made of sapphire instead of glass.
This sapphire is not the same as naturally occurring sapphire gemstones, but a man-made version. Aluminum oxide is melted in specialized furnaces. When liquid aluminum oxide is allowed to cool slowly, it forms a large crystal. The sapphire crystal is cut to form screens.
In analyzing sapphire, it is important to understand that in theory sheets much thinner than a human hair can be cut from the crystals. New technologies are being developed to make it commercially possible. A human hair ranges from 17 to 181 microns (millionths of a meter). In comparison, most glass screens on mobile phones are of the order of a millimeter (thousandth of a meter). For reference, take a look at the fingerprint sensor that is built in the home button of the iPhone 5S. The Touch ID sensor is only 170 microns thin.
In comparing the cost of sapphire to Gorilla Glass, it is important to not make the mistake of comparing the cost of Gorilla Glass which has been produced in large volumes for a while with the cost of sapphire screens which have been produced in very small quantities so far…Read more at Forbes
