The U.S. Patent and Trademark Office just published another patent from Apple that revolves around an interactive 3D display system, or a hologram. Apple filed for the patent in Oct. 2012, and according to Apple Insider, it combines a number of "known display techniques" to create this version of a hologram.
The idea is that you would be able to interact with projected images that are just hanging out mid-air. You could control and manipulate the images with swipes and other gestures. Imagine pinching and zooming a hologram.
Apple's method of projecting this hologram includes a display system, an optical system, and a sensor assembly. It involves infrared lasers and a non-linear crystal. Which is all to say that digital interactive images will be created.
Keep in mind this is just a patent filing. Apple files lots of patents all the time, even if the inventions described never come to reality. Still, it's interesting to take a look at them to get an idea of the stuff Apple dreams up. [Apple Insider]