Creating the Illusion of Reality
Figure 1: Example of convergence and accommodation cues.
Displaying the Illusion of Reality
Now knowing what the display hardware needs to simulate, lets take a look at what is currently available and what may be available in the future. Starting off with the most common new type of display, the stereoscopic display, otherwise known as 3D TV and 3D cinema. One common feature to all these displays is that they are able to display different images to each eye. There are currently a number of different methods to achieve this, but most of these use glasses that the block one eye from seeing the image intended for the other eye. This may be done by using filters (such as polarising or mutual density (MD) filters) or eclipsing glasses using LCDs. An alternative method that does not require glasses, is the Parallax Barrier method. This method uses a simple grating placed in front of the screen. This grating blocks the light from pixels meant to be observed by the one eye from reaching the other eye. Currently the biggest hurdles to overcome with this method is that viewer(s) are required to be seated at certain positions for the display to work. One common problem with stereoscopic displays is that they cause headaches in some users. This is due to the fact that the cues of accommodation and convergence are conflicting with the stereoscopic cue. This in turn means that user’s brain needs to constantly resolve these conflicting cues, which over time (due to the extra effort) can lead to headaches.
Figure 2: Parallax Barrier diagram.
Figure 3: The Holovizio display.
Figure 4: A cross stereo photo of the Light Field Display.
Figure 5: Augmented Reality maintenance using an HMD.
Figure 6: The RD display from Brother Inc.
The Future of the Illusion
Looking a bit further into the future there are two new technologies that may one day offer the ultimate in personal display technology: The Contact Lens Display and the Bionic Eye. The Contact Lens Display is an ongoing reseach project to create a display that is integrated into a contact lens. This should allow for users to have instant access to a computer without having to carry bulky display devices around with them. At the moment the research is still far from creating a working prototype, but could one day be the future of displays.
Figure 7: Contract Lens display.
Figure 8: Schematic of the Bionic Eye.As these technologies improve it may one day be impossible to distinguish between what is real and what is mearly a figment of our digital imaginations.