Tactus Technology is a company that develops a tactile user interface for touch-screen devices.
When needed, transparent physical buttons emerge from the screen and users can push them as required. When disabled, they recede back into the screen leaving the original flat touch-screen surface.
Shown at the recent CES2013, there’s a report and video from the BBC at
http://www.bbc.co.uk/news/technology-20970928
More details about the company can be found at