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What are the Different Types of 3D Glasses?

Matt Brady
Matt Brady

All types of 3D glasses can be divided into two categories: passive and active. Active glasses interact wirelessly with images on a screen to enhance 3D viewing, whereas passive glasses do not. Passive ones have been around since three-dimensional viewing first arrived in the 1920s, and they are themselves divided into two major subcategories: anaglyphic and polarized glasses.

Practically anyone who has ever seen a 3D movie is familiar with anaglyph glasses, which feature a combination of red and blue lenses. Anaglyphic 3D works by projecting two identical but slightly offset images on a screen, each image tinted with a different color. To the naked eye, an anaglyphic image appears blurry, with reddish and bluish hues. The glasses use color-filtering lenses to target one image to the right eye, and another to the left; the result is that each eye sees a different image, but the mind is tricked into believing it sees only one. The mind compensates for this by focusing in between the two offset images and blending them into one, which creates an illusion of depth.

A girl wearing passive 3d glasses while watching a movie.
A girl wearing passive 3d glasses while watching a movie.

Passive polarized glasses operate on the same basis as anaglyph glasses, only they filter light waves rather than color. Again, two identical and slightly offset images are superimposed, except in this case each image is polarized to project light differently than the other. With polarized 3D glasses, each eye only processes one image. Again, however, the mind is tricked into blending the two images into one, creating a 3D experience. Unlike anaglyphic 3D, which can be projected from any screen, polarization 3D works best with screens able to relay different light frequencies without sacrificing picture quality.

A boy wearing active 3d glasses while playing a video game.
A boy wearing active 3d glasses while playing a video game.

On a simpler scale, Pulfrich glasses can also create a 3D effect, but only with objects moving across the viewer's plane of vision. These glasses have one completely transparent lens, and another that is heavily tinted. As an object moves across the visionary plane, the image is immediately transmitted to the eye through the transparent lens, but the tinted lens causes a slight delay. This delay causes the brain to add more depth to the image, creating somewhat of a 3D effect.

Passive polarization glasses are used in many movie theaters.
Passive polarization glasses are used in many movie theaters.

Since the advent of LCD technology, which is capable of digitally transmitting images at super high-speeds, 3D glasses have made great technological leaps and bounds. Today, active shutter glasses are able to communicate wirelessly with an LCD display, interacting with the action on the screen via infrared signals. This enables the lens on active glasses to shutter back and forth between different light filters, further enhancing the 3D viewing experience.

Another significant upside to active technology is that it is adaptable to 3D TV sets. A 3D-ready television set, a pair of active shutter glasses, and a stereoscopic sync signal connector will allow the LCD display and glasses to communicate with one another. A growing number of television broadcasts are being produced to take advantage of this technology.

Discussion Comments

anon966997

What kind of glasses are suitable for a NC900C-A Digital Cinema Projector.

anon311132

I don't like wearing the theater's 3d glasses. What kind of 3d glasses should I buy to watch 3d movies at the theater?

anon269578

Can we watch the 3d on a 2d laptop and how?

klo

@GolfForLife - You make some pretty interesting points. Technology is often a main factor in how art forms develop. However, I don't think every single technological advance has as significant or revolutionary influence on an art form as the electric guitar had on music. Some technologies just end up creating fleeting fads in their respective art forms. There have been plenty of these in every art form.

The keytar in music (a sort of guitar shaped synthesizer) was thought to be a pretty unique invention in its time, but when musicians use them nowadays, it's usually out of humorous irony. Another good parallel to the use of 3D in films is the fish eye lens in photography. They do create a very unique effect, but when they're overused, the effect becomes obnoxious and difficult to take seriously.

Anyway, I think the widespread and borderline excessive use of 3D in films will die out within a few years. It just doesn't add enough to the experience or allow enough innovation for the entire film medium to really take hold.

GolfForLife

@TimeTheorist - If you really think about it, this "phenomenon" isn't so unusual after all. New technology and artistic mediums have been closely linked for as long as either have been around. In music for instance, look at the way the electric guitar influenced the art form. If there had never been that particular advance in technology, rock n' roll and so many other styles would never have existed as we know them.

So, the point I'm trying to make here is that technological advances are often directly responsible for bringing art forms to places people never thought possible. You don't have to like this new 3D (heck, it bugs me too sometimes), but you might as well accept that it's here to stay and that it's going to keep influencing films.

TimeTheorist

Does anyone else think that this whole 3D movies phenomenon has gotten a little out of hand in the last year? I realize that significant improvements in the technology have been made in the last couple of years but I don't think that means that every vaguely fantasy or action related movie should be in "real-D".

I'll admit it, the 3D aspect of Avatar was pretty amazing. But they shot that movie with special 3D cameras. The 3D in that movie was designed to be a significant part of the film, and really enhanced the experience. Since then however, I've seen so many movies where the 3D just hurt the experience or was completely unnecessary. How long until every movie requires the viewer to wear those annoying glasses?

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    • A girl wearing passive 3d glasses while watching a movie.
      By: bevangoldswain
      A girl wearing passive 3d glasses while watching a movie.
    • A boy wearing active 3d glasses while playing a video game.
      By: godfer
      A boy wearing active 3d glasses while playing a video game.
    • Passive polarization glasses are used in many movie theaters.
      By: Deklofenak
      Passive polarization glasses are used in many movie theaters.