A fresh Apple patent has been discovered that promises to make all iPhones and computers just like Tony Stark's talking, holographic assistant in Iron Man. Well, it's a start at least and Apple's ideas include an affordable, compact 3D imaging and display system that can be used for input and more. The diagram below from Patently Apple shows one aspect of the 3D system in operation.
Apple's plan is to give the user feedback with audio and visual signals as they provide 3D input in a defined space. This space would be scanned continually and the results of user action displayed in real time. Not only this, but a projection beam could be used to create holographic images within the space.