Sony announced the Xperia Sola yesterday, and among some mid-tier specs and an unfortunate hunk of Gingerbread, there was a pretty unique (if gimmicky) feature to be found: "floating touch." One of Sony's research engineers has posted a quick writeup explaining how the touch-free finger-sensing technology works. According to the engineer, mutual capacitance — which is used on most touchscreens — has many sensors that can pick up two distinctive, physical touch events. The Sola's screen is different, however: it uses a mutual capacitance sensor to pick up physical touch, but it also uses a separate self capacitance sensor to pick up signals up to 22mm away from the screen.
Right now, the technology has few uses. Sony has enabled hover events in the web browser so that links will highlight when you hover over them and so that drop down menus like those on our site will open, but that sort of functionality doesn't extend to any other Android apps yet — support needs to be added by developers. Fortunately, Android 4.0 does include an API for hover events, and once the Xperia Sola does get upgraded to that version of the OS, you can expect the technology to get more of a workout. For example, hovering over menu items in holo-themed apps in Android 4.0 brings up a tooltip. Google's definitely supporting the feature, but whether "floating touch" will really make a difference or not will depend on how third-party developers integrate hover events in their apps.