IMAX Glasses and Polarized Light
Posted June 11, 2008on:
I was just at the IMAX this week on a school trip and I asked to keep two pairs of the glasses for my classroom. I asked. I’m not one to steal, even something like these inexpensive 3D glasses.
The way IMAX creates 3D is by polarizing the image on the screen so that light for the left eye is 90° out of phase with the light for the right eye. You can easily demonstrate this by first placing the glasses over top of one another, left lens over left lens. You can clearly see through both the doubled left and right lenses as in the picture on the right. The picture below shows the left lens of the front glasses over the right lens of the rear pair. The middle lens pair is black. You can click on these images to get a full size view.
Now turn one pair of glasses 90° to the other and cover the left lens with the rotated left lens. The glasses are now dark. Move the rotated left lens over the right lens and the image is clear again. Now repeat this with the right lens from the beginning. Clearly the left and right lens are out of phase.
I’m not sure how they create this image on the screen. My best guess is that they have a dual projection system that goes through similarly polarized filters. I believe that the separation distances are going to generate the depth. If someone knows for certain, please post the details.