A group of US researchers have come up with a novel new interface for mobile devices, which puts a touch sensitive panel on the back of the unit.

The idea is that users then have a full screen view to work with. The boffins claim the technology solves the problem of fingers getting in the way on touch screen devices like the Apple iPhone – a phenomenon apparently known as the “fat finger problem”.

The device would have what appears to be a transparent display so that the shadow of the user’s fingers can be seen through the screen but would not be in the way of the content. This could allow users to scroll around a web page, type an email or navigate a map without those pesky digits getting in the way.

LucidTouch also supports multi-touch input, allowing users to operate the device simultaneously with all ten fingers.

“Touch input on the small screen of a mobile device is problematic because a user’s fingers occlude the graphical elements he wishes to work with. LucidTouch is a mobile device that addresses this limitation by allowing the user to control the application by touching the back of the device. The key to making this usable is what we call pseudo-transparency: by overlaying an image of the user’s hands onto the screen, we create the illusion of the mobile device itself being semitransparent,” said the researchers, who are based in the Microsoft Research and Mitsubishi Electric Research Labs.