When you think of a touch screen you think of the front display. With that display you interact with your device by swiping up, down, left or right. In the future we may not be using the front display at all to interact with our smartphones or tablets.
Google has filed an application with the USPTO for back panel touch controls on a smartphone and even tablets. The intriguing part about the technology is that it will be able to distinguish contact from holding the device normally and contact intended to control an app or part of the device.
The patent sounds a lot like the PlayStation Vita's back touch panel, which is in place to free up the front OLED screen. It's possible that Google could be doing something similar in order to free up screen real estate from a users fingers, but that's just speculation. If it were to happen though, no doubt Sony would give Google a bit of flak.
Apple filed an application for a similar patent in 2006 for future tablets, before the making of the iPhone, but the USPTO denied it. It's possible that Google's application will get denied, or the USPTO may find it unique in that the patent is for a touch panel on the back of an Android smartphone and tablet.
The technology sounds great, especially for a device like the Note 2 with its 5.5-inch screen since some people have trouble using the device with one hand. It seems like it would be very tedious on a device with a smaller form factor though. Besides, what would happen to the back touch panel if you dropped your phone by accident? Again, it's all speculation at this point, we'll just have to wait and see what Google ends up doing with this.