3D displays: How do they work?
By Loh Ving Sung GooglePlus
06 January 2012 – 3D is starting to get cheaper and more accessible, and it was only two years ago when they started showing up in movie theatres (e.g. Avatar) and more recently mobile devices – like the HTC EVO 3D and Nintendo 3DS.
So far they have been introduced to varying degrees of success. Some movie-goers have already declared that 3D ‘jumped the shark’. But we believe it is matter of time before we bask in widespread 3D in our gadgets. We are going to look at how images on a screen trick your brain and how colourful glasses help us see what’s on screen.
Simply put, most 3D systems merge two images together to display a 3D image. Let’s take a look at the most prevalent tech that gave us movies like Piranha 3D.
The original red and blue lens (anaglyph) glasses are perhaps the most iconic part of 3D - it is mainly used for 3D television and was used in many older 3D movies. Two images are then displayed on a screen, one in red and the other in blue, and the coloured filters on the glasses will only allow one image to enter each eye and your brain will then interpret both images as 3D.
With the coloured tinted lenses however, it is tough to enjoy a movie in colour, so the image quality is not as good as the polarised system.
Modern system are called polarisation, it still uses glasses and two images, but they have different polarisation. The glasses allow only one of the images into each eye because they contain lenses with different polarisation. Your brain will do all the work after that.
Autostereoscopy takes away the need glasses or lenses, and is designed to fool the brain with a stereo view for the user. This means that each eye sees a different image from the display, which the brain interprets it as a single 3D image.
Called the parallax barrier, a light barrier is placed over the LCD display which directs light from alternate pixel columns to each eye. Basically, the layer consists of a series of tiny slits that allow each eye to see a different set of pixels.
It allows instant switching between 2D and 3D modes too, because the aforementioned light barrier can be turned off.
While it does away with the bulky, unfashionable glasses it will require the user to find that ‘sweet spot’ to experience 3D. Once the user stands too far away or at the wrong angle, they will lose the ability to interpret 3D.
Smartphones like the HTC EVO 3D or LG Optimus 3D are glasses-free 3D and rely on parallax barriers, and the downside of course is starting with the screen at the right angle which is okay if you looking at a short clip. With extended gaming sessions or longer 3D movies however, holding the phone may be a problem.
You can also create content with your mobile devices - the LG Optimus Pad and HTC EVO 3D allows you shoot 3D images and video, via dual-lens 5-megapixel cameras. You can then share out either on YouTube 3D or a 3D TV, assuming you can afford one of these bad boys.
Make or Break?
Practically speaking, there are still some snags to 3D, with Nintendo issuing a health warning to children under six that are trying to use their 3D screens.
So will we be looking at more 3D devices?
It isn’t extremely popular yet, and considering the amount (or lack thereof) of 3D mobile devices, we suspect it will remain that way at least until 3D becomes an intuitive and comfortable process.