The system would work like this: each pixel would be projected onto a reflective, textured surface, which is then bounced into a viewer's left and right eye separately, producing the 3D, or stereoscopic, effect. it would sense the locations of both eyes of the each viewer, so multiple people could watch from a variety of angles.
The goal of the technology they've cooked up is "inexpensive auto-stereoscopic 3D displays that allow the observer complete and unencumbered freedom of movement," according to the patent application the Patent Office granted yesterday. In other words, 3D displays should have no need for special glasses, and viewers shouldn't be limited by viewing angle, or be forced to sit and not move in order to see the 3D effect.
Interestingly, the patent breaks down why they think current offerings for glasses-free 3D aren't good enough, including parallax barrier, volumetric, and hologram.
A parallax barrier display, which is what is used in some auto-stereoscopic phones and likely the Nintendo 3DS, uses one liquid crystal display layered under another. Each has tiny stripes that will hide certain pixels so that some are only visible to your left eye, while others will only be seen by your right eye. In that way, each eye gets its own image, producing the illusion of 3D without the need for glasses.
Toshiba and Sharp both have prototype glasses-less 3D TVs and expect to begin selling them in Japan by the end of the year. Toshiba's method is to use a fast, powerful processor to take a 2D image and simultaneously create nine images of it from nine different directions, in real time, and display it on a high-definition LED TV.
Apple says those aren't good enough because of the processing power needed for the hologram style of Toshiba and Sharp, and the limits on movement or more than one viewer with parallax. "A need still remains for highly effective, practical, efficient, uncomplicated, and inexpensive autostereoscopic 3D displays that allow the observer complete and unencumbered freedom of movement," the patent application reads.
Of course, like any patent, this doesn't mean we should expect an Apple-branded 3D projector anytime soon. The original patent was applied for in 2006, and these are the kinds of technologies that tech companies like to keep in their back pocket, just in case.