Researchers at HP Labs have built a small, multi-angle, glasses-free 3D display that could allow for smartphones, tablets, and watches to produce Princess Leia-like holograms. The current prototype devices can produce full-parallax 3D images and videos that are viewable from up to a meter, within a 90-degree arc — and, like the Star Wars hologram, the 3D image or video varies as you move your head up and down, or around the display.

Over the last couple of years, a few portable devices with glasses-free 3D have come to market — most notably the Nintendo 3DS. Most of these devices use horizontal parallax, which does produce a 3D image — but only in the horizontal (left/right) plane, and usually only within a viewing arc of a few degrees; move your head too far to the side, or just slightly up or down, and the 3D effect is broken. The prototype display produced by HP Labs, however, produces full 3D images that appear to protrude up to one centimeter in front of and behind the display. “For example, if you were to display a 3D image of planet Earth with the North Pole facing out from the screen, by turning your head around the display, you would actually be able to have a view of any country on the globe, you would be able to see all the way around,” says David Fattal, the project’s team leader.

The technology behind HP Labs’ 3D display is essentially a special backlight. A modern LCD monitor, like the one on your laptop, usually has a backlight that consists of LED strips along the bezel. A strip of LEDs along the edge doesn’t provide very even illumination, and so a diffuser must be used. A diffuser is basically a thin piece of plastic that takes the light source and spreads it evenly across the full width of the display (though, if you’ve ever seen a cheap or old LCD monitor, the diffuser sometimes does a pretty bad job of it). In HP’s 3D display, the diffuser has been etched with millions of refracting waveguides that send specific points of light in 64 different directions — so, depending on where your head is, you receive a different beams of light, and thus a different image. This approach has allowed HP Labs to produce a backlight capable of 64 different views, producing 3D still images and 30 fps videos at 88 pixels per inch.

Moving forward, the researchers say that a viewing angle of 180 degrees should be possible — good for televisions and other large displays. The small size of HP’s prototype display (six inches) and relatively high resolution are strong indicators that the technology could find its way to mobile devices, too. It’s worth noting that HP Labs is by no means the only group working on glasses-free 3D technology, too: MIT has a glasses-free holographic TV, and back at CES 2012 ExtremeTech checked out a bunch of glasses-free 3D TVs that might eventually find their way into your living room. (See: Is holographic storage finally coming to market?)

While it’s certainly nice that the display side of the equation is coming along, we shouldn’t forget that holographic displays require holographic content. A holographic display doesn’t just take a 2D movie and convert it into a hologram that you can move your head around — for that, you need footage that has been filmed with a holographic camera. Some work is being done in this area by camera makers such as Arri, but we’re still a long way away from recording and displaying true holograms. A more likely possibility is computer-generated holograms, where it would be relatively easy to produce holographic output from the 3D models that make up most modern video games.

Now read: 3D TV is dead

Research paper: doi:10.1038/nature11972 – “A multi-directional backlight for a wide-angle, glasses-free three-dimensional display”