Why Glasses-Free 3D Is Going To Be A Small-Screen Hit

By Jacob Aron

The latest generation of 3D technology has seen mixed success at the cinema, and 3D TVs are yet to establish themselves in the living room. Perhaps the true home of 3D is on mobile devices, where you don't even need special glasses. New Scientist takes a look at the future of 3D on the move.

How can you have 3D without glasses ?

Simple – you do it all the time. We perceive the world in three dimensions because our eyes see two slightly different images and our brain interprets the difference as depth. Films or games displayed on an ordinary 2D screen don't contain any of that depth information, so we perceive them as flat surfaces. 

Naked eyes will do (Image: Noah Berger/Bloomberg/Getty)

Traditional 3D screens add depth information back in by simultaneously displaying or rapidly alternating between two images, relying on viewing glasses to show the separate images to each eye. The red and cyan filters of the original 3D specs have now been replaced by the polarised light systems used in cinemas or active shutter glasses for 3D TVs, but the principle is much the same.

Everyone would like to get rid of those 3D glasses, which is why screen manufacturers are researching two other techniques. Parallax barriers add a slotted barrier in front of the screen: each slot reveals a thin strip of the screen to one eye while the adjacent barrier blocks it from the other, so that all the slots together create separate images for each eye. Another technology, lenticular lenses, achieves the same effect with columns of bumpy lenses that redirect light to each eye – you might have once owned a ruler that used a very basic version to make moving or 3D images.

Do any commercially available screens use this technology ?

The newly released Nintendo 3DS uses a parallax barrier to display 3D games. You can read our impressions of the device here, and see some images of the screen under a microscope at technology news website TechOn. It's not the first glasses-free 3D device though, as Fujifilm has also developed a range of 3D cameras with a lenticular lens display for viewing your 3D photos.

Mobile manufacturers are starting to jump on board as well. LG will soon release the Optimus 3D, the first smartphone with a 3D display – although it's not clear which of the two technologies it uses – and HTC this week announced its own Evo 3D with a similar screen.

Can't I have the same technology in my TV ?

You'll notice that all these gadgets are designed to be used by one person holding the screen a short distance away from their face. That's because the glasses-free 3D effect only works if your eyes are in certain positions – fine for a handheld device, but less impressive on a big screen in your living room.

That hasn't stopped TV manufacturers from trying, but you're unlikely to be throwing away your old set just yet. Toshiba's Regza GL1 series, launched in Japan last December, only works at a viewing angle of less than 40 degrees and at a distance of a metre or less, depending on the screen size. Other manufacturers have shown off prototypes with similar limitations, and earlier this week TV manufacturer Samsung said it will be "difficult" to bring glasses-free 3DTV to market within the next 10 years.

So what's the future of 3D in my pocket ?

With glasses-free 3D unlikely to hit bigger screens any time soon, mobile manufacturers have time to shine. The 3DS can be used to take 3D photos and will be able to download some 3D movies, but it's primarily a gaming device and wider use will be limited.

It's more likely that the Optimus 3D and Evo 3D will determine the future appeal of 3D on the move. Both phones run Google's Android operating system: Google itself is already on board with its YouTube 3D app, and its open platform means anyone can create apps that take advantage of the phones' 3D screens. We'll have to wait until the phones hit the market later this year to find out what the extra dimension can do for your mobile.