Apple’s latest patent application titled “Oleophobic coating on sapphire” published today by the U.S. Patent and Trademark Office may be the very first hard evidence that the Cupertino giant is indeed planning to include sapphire crystal in its next generation iPhone lineup. In addition to the illustration of an iPhone on the filing’s cover page, AppleInsider notes that the document “repeatedly mentions sapphire displays in phones and tablets”.
The application details methods by which an oleophobic or oil-repelling coating can be applied to a sapphire slab prior to installation in a mobile device. Apple iPhones and iPads since the iPhone 3GS have come with the oleophobic coating. However, its method of application used on Gorilla Glass does not necessarily apply to a material like sapphire. Apple highlights that normal methods of coatins and certain oleophobic treatments do not fair well when applied directly to sapphire glass.
“Apple proposes a transitional layer be disposed between the base substrate and the oleophobic coating. Further, a surface layer may be composed of alumina, silica or a combination of the two. In one embodiment, the transitional layer consists of a combination of base layer materials and other components like alumina-silica glass, a form of which is marketed by Corning as Gorilla Glass. The layer is applied via a sputtering process, physical or vapor deposition (PVP or CVP), or other suitable method.
Apple notes the end result of this sapphire-transitional layer-surface layer sandwich is a largely continuous and uniform structure that retains the benefits of sapphire’s hardness, while allowing for the operable application of an oleophobic coating.“
While it still remains unknown whether Apple will use sapphire as a display material in its upcoming ‘iPhone 6’ or not, the invention certainly solves a major hurdle in the way of mass production.