I remember as a kid when I went to a 3D movie and you would have to wear those glasses with one blue eye and one red. Then a couple years later, you don’t need those red/blue glasses but these clear ones. And now you don’t need glasses at all.
Why is that?
In: 9
Stereoscopic vision works because your right eye sees slightly to the right of things and left slightly left.
To produce a stereoscopic image, a projector projects one image recorded to the left and one to the right slightly.
These are then projected at a slight offset from each other, but we have to find a way to make it so only one eye sees one image.
We used to do this by displaying two different color-altered images and wearing colored lenses. A red lens won’t let blue light through and a red lens won’t let blue light in. This allowed the right eye to see the left image and the reverse for the other eye.
Now, we can use polarization to do this.
Think of polarization as “lining up” waves of light. Instead of absorbing, reflecting, and passing based on color, it does do based on alignment.
One image for one eye is polarized in one way and the other eye the other. We’ll simplify by calling the left lens vertical and right horizontal, though they’re usually polarized a little more complexly than that.
Now, they project one image using vertically aligned light and the other with horizontally aligned light and they’ll inky make it through the respective lenses!
Of course, there’s a bit more complexity to it, but that’s the gist!
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