On the market for an iPhone? Here's a breakdown of all the currently shipping iPhones from Apple.
Patent: Multisided Full Screen Touch iPod
Apple describes the problems related to the use of a touch interface screen in the more traditional screen + touch interface together. The problems include obscuring the screen with your hand and introducing smudges onto the screen.
Instead the use of "back side touch" would eliminate these issues but still provide user interface feedback with the use of an on-screen cursor which identifies where the touch-interface is being used.
More specifically, a force-sensitive touch-surface is provided on a first or back-side surface of the device through which a user provides input (e.g., cursor manipulation and control element selection/activation)," the company wrote. "On a second or front-side surface, a display element is used to present one or more control elements and a cursor that is controlled through manipulation of the back-side touch-surface.
The patent is credited to John Elias who was one of the founders of Fingerworks, a company who had done much work in the field of touch-interfaces. Apple acquired Fingerworks in 2005.
Raw Data: Patent Application #20070103454