Typical attempts at a glasses-free 3D display have trouble with viewing angles; we're all too familiar with having to sit in a sweet spot to get the effect. HP Labs might have just solved this last problem with a prototype 3D LCD that would better accommodate the real world. The display's backlight has nanopatterned grooves that send blue, green and red in multiple directions, letting the LCD show only the light that would be seen from a given viewpoint. Those positions are set in stone, but they're both abundant (200 for photos, 64 for video) and can spread across a wide 180-degree viewing arc. At a thickness of as little as half a millimeter, a production LCD could easily be thin enough for a mobile device, too. The catch isn't so much the screen as the content. Producers need an image for every possible viewpoint, which could create a fair share of logistical problems: even though footage wouldn't necessarily require 200 cameras, it could limit fully immersive 3D to computer-generated visuals or else consume a massive amount of bandwidth. If those are the biggest barriers, though, we're still that much closer to the holographic smartphone we've always wanted.