Although the 1950s are most often considered the 3-D movie decade, the
first feature length 3-D film, "The Power of Love," was made in 1922.
Since that time the use of 3-D technology in theaters and on television
has drifted in and out of mainstream popularity. But, whether you've
used them for the big screen or at home in front of your television,
you have to admit 3-D glasses are incredibly cool.
with red/blue lenses
They make the movie or television
show you're watching look like a 3-D scene that's happening right in
front of you. With objects flying off the screen and careening in your
direction, and creepy characters reaching out to grab you, wearing 3-D
glasses makes you feel like you're a part of the action - not just
someone sitting there watching a movie. Considering they have such high
entertainment value, you'll be surprised at how amazingly simple 3-D glasses are.
In this article, we'll take a look at the two most popular types of 3-D
glasses in use today. But first, let's take a look at something called binocular vision.
Most human beings come equipped with two eyes and an absolutely amazing binocular
vision system. For objects up to about 20 feet (6 to 7 meters) away,
the binocular vision system lets us easily tell with good accuracy how
far away an object is. For example, if there are multiple objects in
our field of view, we can automatically tell which ones are farther and
which are nearer, and how far away they are. If you look at the world
with one eye closed, you can still perceive distance, but your accuracy
decreases and you have to rely on visual cues, which is slower.
Photo courtesy Dan Metz
To see how much of a difference the binocular vision system
makes, have a friend throw you a ball and try to catch it while keeping
one eye closed. Also try it in a fairly dark room or at night, where
the difference is even more noticeable. It is much harder to catch a
ball with only one eye open than with two eyes open. If you want to try
a quick test of your binocular vision, visit this Web site.
The binocular vision system relies on the fact that our two eyes are
spaced about 2 inches (5 centimeters) apart. Therefore, each eye sees
the world from a slightly different perspective, and the binocular
vision system in your brain
uses the difference to calculate distance. Your brain has the ability
to correlate the images it sees in its two eyes even though they are
If you've ever used a View-Master or a stereoscopic viewer, you
have seen your binocular vision system in action. In a View-Master,
each eye is presented with an image. Two cameras
photograph the same image from slightly different positions to create
these images. Your eyes can correlate these images automatically
because each eye sees only one of the images.
Photo courtesy Dan Metz
When you use a View-Master viewer, it's easy to see how your binocular vision system works.
In a movie theater, the reason why you wear 3-D glasses is to feed different images into your eyes
just like a View-Master does. The screen actually displays two images,
and the glasses cause one of the images to enter one eye and the other
to enter the other eye. There are two common systems for doing this:
Red/Green or Red/Blue
the red/green or red/blue system is now mainly used for television 3-D
effects, and was used in many older 3-D movies. In this system, two
images are displayed on the screen, one in red and the other in blue
(or green). The filters on the glasses allow only one image to enter
each eye, and your brain does the rest. You cannot really have a color
movie when you are using color to provide the separation, so the image
quality is not nearly as good as with the polarized system.
The red and blue lenses filter the two projected images allowing only one image to enter each eye.
At Disney World, Universal Studios and other 3-D venues, the preferred
method uses polarized lenses because they allow color viewing. Two
project two respective views onto the screen, each with a different
polarization. The glasses allow only one of the images into each eye
because they contain lenses with different polarization.
The polarized glasses allow only one of the images into each eye because each lens has a different polarization.
There are some more complicated systems as well, but because
they are expensive they are not as widely used. For example, in one
system, a TV screen displays the two images alternating one right after the other. Special LCD
glasses block the view of one eye and then the other in rapid
succession. This system allows color viewing on a normal TV, but
requires you to buy special equipment.
3-D glasses with red/blue lenses