Introduction

Computer users have been able to get real 3D images for quite some time, often by using clunky shutter glasses with a CRT monitor. However, now that LCD monitors are standard it is no longer possible to use relatively cheap 3D glasses to provide a real 3D image (due to the fact that LCD?s update the image in the same way as a CRT). 3D monitors provide a real depth perspective to games and other applications, allowing for a new level of realism and sensory immersion.

3D LCD technology has existed since the very first commercial monitors were on sale, but they were prohibitively expensive and lacked the image quality of the current panel generation. The most popular form of 3D LCD technology is called ?autostereoscopic technology? and is able to provide a 3D image without any glasses!

This technology works by diverting each column of pixels to an individual eye, essentially halving the vertical resolution but providing a unique image to each eye. By displaying a correctly rendered image on the monitor it is then possible to trick the brain into believing that the two 2D images are a single 3D scene.

There are two ways of directing the light to each eye, either by using a parallax barrier or a lenticular lens. The two diagrams below illustrate how the light from ?left? and ?right? pixel columns reaches the eye:

Parallax Barrier


In the parallax barrier a mask is placed over the LCD display which directs light from alternate pixel columns to each eye. Parallax barrier displays allow instant switching between 2D and 3D modes as the light barrier is constructed from a layer of liquid crystal which can become completely transparent when current is passed across, allowing the LCD to function as a conventional 2D display.

Lenticular Lens


In the lenticular lens, an array of cylindrical lenses directs light from alternate pixel columns to a defined viewing zone, allowing each eye to receive a different image at an optimum distance.