3D Glasses Explained
3D movies have become a pretty popular tradition. All around the world, IMAX cinemas provide the 3D experience to movies fans all over the world. Those with the money have even bought their own 3D TVs at home to enjoy the awesome experience 24/7.
3D movies are way more awesome than 2D ones. As a result, more movies are being shot with 3D cameras while the old ones are being converted. The common factor while watching 3D movies is that you need 3D glasses. The 3D TV is also a good necessity but it is not a must for you to have a 3D TV in order to watch 3D videos as we’ll see.
How do they work?
Why the glasses? 3D works by providing two sets of videos, one for each eye. The glasses are used to make sure that each eye only sees the frame that is intended for it. 3D glasses have special lenses that make this possible. The left frame only gets filtered to the left eye and the right frame is only filtered for the right eye. What sets 3D glasses types apart, is how they accomplish that.
3D Glasses Types
ANAGLYPH (RED/CYAN) GLASSES
They are the most common and simplest type of glasses available. Anaglyph glasses have different coloured lenses usually Red and Cyan. In other cases, the glasses might have other colour combinations e.g. Green and Magenta. The coloured lenses filter each frame to its intended eye corresponding to colour differences in the 3D video. The main advantage of Anaglyph 3D glasses is the low price and that there is no need for a special display for watching anaglyph 3D. You can use any standard display or even print an anaglyph picture on a paper. The disadvantage of Anaglyph 3D glasses is the low 3D quality they offer. This is why they are not currently being used in any of the modern cinemas or with 3D TVs today.
The biggest advantage of Anaglyph glasses is that they’re super cheap and they do not require a special 3D TV. With anaglyph, you can use any display. You can even print an anaglyph picture on paper and it will work. The bad thing about them is their awful picture quality. Their poor quality is the reason why they’re never used in cinemas.
POLARIZED 3D GLASSES
Polarized glasses are the most commonly used 3d glass type in cinemas and look just like normal sunglasses. They usually have enough front space to enable you to wear your eyeglasses beneath (my brother always does this). These glasses are inexpensive to manufacture and go for pretty friendly prices. They have special lenses that filter frames to the intended eye using differences in light polarization.
Use of these glasses require a compatible 3D display/projector. Polarized glasses provide very good 3D quality hence their use in cinemas. They are also super comfortable, unlike Anaglyph glasses. Their disadvantage is that they require the use of a silver screen with a projector which makes it expensive and slightly decreases the quality of the 3D effect.
There are two types of polarized 3D glasses: linear and circular. Circular glasses maintain the 3D effect even when the viewer tilts their head. This one of the reasons why they are more efficient for use in Cinemas.
ACTIVE SHUTTER 3D GLASSES
They are slightly bulkier than polarized glasses and they have batteries, on/off buttons and a transmitter that syncs the moving shutters for each eye with the onscreen display rate. They are commonly used with 3D TVs and in some cinemas.
Each lens has a transparent liquid crystal that turns black on voltage application, blocking one of the eyes at a time. e.g. when the right eye is blocked, only the left eye sees its intended frames. the 3D effect is great with shutter glasses. However, they are super expensive and are not comfortable. They might cause mild dizziness due to the flickering.
Originally published at Decode.
