In a concept video demonstrating the use of 3D sensing technology, Microsoft shows how 3D sensing would work on a smartphone. With the rumored Microsoft Mobile, formerly Nokia, McLaren smartphone anticipated to have 3D gesture tech to allow a user to interact with the touchscreen without even touching the display, this technology could appear on this or future Windows Phone models.
In a nutshell then, the same tech behind Nokia's 'Super sensitive touch' and Samsung's 'Air view' is extended with one 'transmit' electrode grid and five separate 'receiver' electrode grids. By looking at the relative capacitive interference signals, the software can work out where a fingertip (or, potentially, fingertips - i.e. plural) is and what it's doing (i.e. moving in a particular direction).
I'm a little sceptical about the practicalities of using such an interface out in the real world. After playing with 'hovering' on the Samsung Android phones, I always turned the feature off in the end, feeling that it used extra power for not much gain. Out and about, it's hard enough to execute precise 2D touches and gestures, let alone thinking about how far your thumb or finger is above the screen as well.
However, for artistic applications and for games, I can certainly see how manipulating an interface in '3D' might be more useful, and I'm prepared to be convinced.