How 3D glasses work?

The technology that makes you able to see a 3D (three dimensional) scene happening in front of you in a theater was launched in 1922 and the movie was named “The Power of Love”. A 3D movie would see as if a Blur or out of focus movie if seen without 3D glasses, so how does these glasses convert 2d to 3d? That’s the question everyone is curious about.

A normal person is usually equipped with two eyes, this normal vision is termed as Binocular vision. Under normal condition we can sense the rough distance of many objects are placed in front of us, as which is nearer and which one is at approximately 10 feet or 20 feet etc. but doing this with one eye close can create difficulty. Our eyes are approximately 2 inches (5 centimeters) apart that allows us to see the world from a slightly different perspective, then our brain correlates the vision.
A 3D glass usually comes in colors as Red/Green or Red/Blue are necessary to wear as to feed different images through your eyes. The colors on the glasses are actually filters. The screen shows two pictures at a time with a different perspective, one in red and the other in green or blue. Hence only one type of image enters through the dedicated filter, i.e. the images in red passes through the red filter on the glass and similarly with the other filter. The images then combines and your brain have to do the remaining effort to sense a three dimensional effect in front of you. As told earlier a slightly different vision is fed in both of the eyes and the brain then allows us to approximate distance of objects nearer or away from us, which is actually not the real distance between the objects but the distance between the two colored images fed through the 3D glasses. That is the reason why we feel objects flying and coming closer to us even though we are at a great distance from the screen of the theater. Finally we are a part of the action happening in front of us

This technology of Red and Green/Blue filters is a bit new and emerging technology. Another technology that allows 3D viewing is “Polarization”. Here the glasses contains lenses with different polarization. Two different projectors project the scenes onto the screen containing different polarization, the lenses in the glass allows only specific polarized radiation to pass through it and then you are able to see a 3D scene.
3D LCD are also available nowadays, on which you can see a 3D movie at home also without any type of special glasses. So how do they work?
Answer is simple. The LCD is equipped with slits of two types on the LCD. When one type of slits are opened they show us one perspective blocking the other, and the other perspective is shown when the other slits opens. This transaction of slits happens so quickly that we can’t observe it with our naked eye, but we can witness a 3D movie with our naked eye .

                                                                                         Wajahat Jamil
                                                                                         Third Year
                                                                                         Industrial & Manufacturing Dept.