Glasses-free 3D effect by using a parallax barrier LCD. These displays have been around for a few years but they’re very dependent on what angle you look at the screen from. Though this shouldn’t be a problem with a small LCD, like the ones you’d find on a mobile phone, it’s not too practical for the telly in your sitting room.
So how does a parallax LCD work? Most people know that when you’re watching a 3D movie and wearing those dorky glasses, a different image is being sent to each eye; your brain mashes these two images together to create a composite 3D image. You may not know that a 3D display incorporates an overlay that is placed in front of the LCD. This is called a parallax barrier and it polarizes the glasses.
Parallax barrier is a little different for it is actually a ‘switching LCD’ that allows for both 2D and 3D imaging without the need for special glasses or goggles. When this switching LCD is switched off, the TFT-LCD displays 2D imaging as normal, but when the parallax barrier is switched on, it controls the way light leaves the display, meaning different patterns of light reach the left and right eye.
credit for above information goes to http://www.3d-mobile-handsets.com/