We’re all used to 3-D at the movies, the technology has existed for years; you wear a pair of different colored plastic glasses that allow your eyes to see different images at the same time, which the brain converts to a 3-D image. It’s all pretty simple stuff. What’s not so simple though, is moving the technology to the home television set.
The reason this is a trickier problem is because of the way television is broadcast versus how movies are shown; specifically, movies are shown by running light through a film frame and then capturing the result on a movie screen. Television images on the other hand are created and displayed on the device we watch. First, with CRT television sets, images were created by shooting the back of a glass vacuum tube that had special chemicals on it, with a type of light gun that would cause the chemicals to light up in certain ways on the back of the tube. The gun would move back and forth, in effect painting the screen as it moved across a line, then again as it moved down to the next line and the next till it got to the bottom. Nowadays, images are shown on flat screen TV’s by sending electronic signals to individual elements on the back of a pane of glass. The individual elements light up depending on which signal is sent and special processors are used to generate the right signals.
Thus the technology needed to create 3-D on televisions is quite different from that used to produce the same result at the movie theater.
To make it happen on a high definition flat screen television, engineers have developed standards for Blue Ray discs that hold 3-D movies that in effect actually hold two versions of the movie that are broadcast almost simultaneously. This is why 3-D movies take up so much more room on a disc than do traditional high definition movies, twice as much actually, because they hold two movies. What happens is, one of the versions of the movie is for your right eye, and the other version is for your left eye. The scenes are all of the same thing, except they are shot at slightly different angles from one another using a dual lens camera that mimics how we have two eyes that see the world around us from slightly different angles.
The standards that are used with Blue Ray discs are the same ones that are used by the companies that make the Blue Ray players and televisions sets, because the glasses that come with these systems are either plugged directly into the television set, or are have an infrared wireless system. They need to be connected to one another because the television actually has a processor that takes date encoded on the Blur Ray disc that tells the glasses which image to show which of your eyes. Thus, while you are watching a movie, your glasses are constantly shifting back and forth watching the version of the movie that was meant for each eye and the end result is what your mind sees, as three dimensional.
And that, in a nutshell, is how 3-D television works.