3D Glasses - Comprehensive Reviews...

3D Glasses - A Short History

Why are 3D glasses needed for viewing 3D movies and 3D TV? Because the best stereo images come from delivering different images to each eye. And the easiest way to accomplish that when people are viewing a flat image is to have viewers wear special 3D glasses with lenses that deliver slightly different versions of the flat image to each eye.

Parallax

Humans naturally see in 3 dimensions due to parallax, which is the overlapping line of vision that occurs when using 2 eyes to view an object. Since our eyes are several centimeters apart, each eye sees an object at a slightly different angle. This slight difference is what causes �depth perception� and our experience of seeing in three dimensions.

Stereoscopic imaging

Stereoscopic imaging (3D imaging) was first implemented back in the 1800s. By looking at two slightly different flat images side by side, parallax was artificially created and viewers had the experience of seeing a 3 dimensional scene instead of a flat photo.

3D movies

When movies came along, there was more experimentation with parallax and the search for more effective ways to manipulate viewers� perspectives. One method uses polarization and two different films shot at slightly different angles. Two projectors are then used to show the movies. Another method prints two different methods onto one film strip. With both methods, the audience has to wear special glasses to complete the three dimensional effect.

3D glasses

There are a many different kinds of 3D glasses that people have worn, depending on what methods are used to produce the 3D movie. Two of the most common have been anaglyph and polarized. Viewers who wear linearly polarized 3D glasses must keep their heads level to maintain the 3 dimensional effect, so that their eyes remain aligned with the light and images that come from the projector. Viewers who wear circularly polarized 3D glasses can still see in 3D if they tilt their heads.

Anaglyph 3d glasses

Eyes see combinations of the 3 primary colors: red, blue and yellow. Anaglyph 3d glasses simply use a different colored lens for each eye. The anaglyph glasses pair one primary colored lens (like red) with one mixed colored lens like cyan (a mixture of green and blue). This blocks out parts of the color spectrum in one eye, and different parts of the color spectrum in the other eye. The difference is enough for each eye to see a slightly different image while looking at the movie screen, causing the brain to process the scene as if it were three dimensional.

3d shutter glasses
Originally developed for gaming and viewing display screens, 3d shutter glasses have evolved into being used to watch high definition TV. The lenses are controlled by infra red, like Bluetooth, and contain LCD (liquid crystal). They are synchronized with the refresh rate of the screen to alternately darken and allow light. In addition, they alternate back and forth between the lenses blocking out light and creating a parallax view.