Originally Posted by Icon Master
I went up after watching a 3D movie to observe the 3D projector used at the local AMC Palace theater and it was a Sony. It was a single lens unit and the projector was huge. The unit was projecting two complete images - one above the other onto a "glass" plate. From there the images went on to the screen. This was a Real 3D setup. From what I have read the Real 3D system uses circular polarization. If that is the case I am guessing that the glass plate consisted of two panes - one of which had clockwise polarization and the other counterclockwise.
With that setup you would be half resolution on one axix and full on the other (I had forgot about that RealD setup with the Sony projecctors). The other, more widely used, RealD setup operates a DLP projector at 144Hz and alternates between right and left images (each at 72Hz or 3 times the original movie's 24Hz rate). An electronic controlled "Z-Screen" is used in the light path to alternative between the two polarization orientations in sync. with the projector. This still allows for passive, polarized glasses to be used and you get full resolution to both eyes. Here is the Wiki