A History of 3D Glasses
With the onset of 3D TV it is likely that we will all put on a pair of 3D glasses in the near future, but what do they do and why do we have to wear them to watch 3D TV?
How 3D Glasses Work
Although there are many different kinds of 3D glasses, they all work to achieve the same end result. In a nutshell, they are essentially trying to trick your brain into seeing a 2 dimensional image projected by a TV set or cinema screen as a 3 dimensional image.
The First Popular 3D Glasses
Most people can remember the first 3D glasses from years ago that were designed to work with anaglyph color filtering. These glasses were usually made out of cardboard with one red lens and one cyan lens; although before 1970 red and green lenses were used.
Anaglyph color filtering was invented in 1853 by Wilhelm Rollmann. The red and cyan anaglyph 3D glasses work by making each eye see a different image. The brain then makes these two images blend together, and the result of this is a 3D image effect.
Theses glasses enjoyed a fair amount of popularity in the past because of the fact that they were the cheapest ones available to view 3D entertainment; however it wasn’t long until people started looking around for new, more effective ways to see in 3D.
Polarized 3D Glasses
Polarized 3D glasses work in a very similar way to anaglyph 3D glasses. It is worth noting that in the early ages of 3D film many cinemas used the polarized method rather than the anaglyph method. Polarized 3D images have been around since 1936 when they were introduced to theatres by Edwin H. Land.
Polarized 3D glasses work by restricting the amount of light that enters each eye. The movie screen that is being watched presents two separate images using orthogonal polarizing filters, which are also in the lenses of the glasses. The brain as with the anaglyph glasses is tricked into blending the images to create a 3D effect.
LCD 3D Glasses
Developments in 3D viewing made way for the invention of LCD 3D glasses. These glasses must be used in conjunction with a liquid crystal display screen which will become dark when voltage is passed through it but ordinarily is transparent. The glasses work in synchronization with the LCD screen.
The glasses become dark over one eye and then the other eye alternately. This is another example of stereoscopy which tricks the brain into seeing the 2D images that are projected as 3D. This method can be quite effective but also expensive with glasses costing around $100.
Side Effects
3D glasses are thought to be a safe way to view 3D entertainment but there are some reports of people experiencing some negative side effects from wearing them and not just the obvious side effect that you look a bit silly!
Some people have reported feeling nauseous while wearing 3D glasses and other people have complained of headaches and general unpleasantness. This could be because of the content of what is being viewed itself rather than the glasses as 3D TV and films tend to be high paced and quite unsettling to watch.
Another reason could be the effect that the 3D glasses and displays have on peoples’ brains. Since 3D viewing involves tricking the brain into seeing two separate images as one, the brain has to work harder to interpret the image which may make some people feel a little odd or even ill.
3D glasses have had an interesting journey up to this point. It is not clear which form of these glasses we will be wearing when 3D TV hits the shops as there has been no standardization of the products yet but you can be certain that 3D glasses will be a part of your viewing experience.