RealD's innovation for the cinema was to eliminate the need to critically align two projectors by installing the polarization mechanism's active electronics into a single digital projector. RealD's patented ZScreen is an active LCD that is placed in front of the single projector to properly polarize the light for sequential display of left and right images.
The ZScreen is a custom LCD that adds polarization to the light passing through it. By synchronizing the angle of polarization imparted with the sequential display of right and left images, it eliminates the need for two projectors.
Polarization matches up well with current theater infrastructures, since movies can be viewed with disposable passive glasses that don't have be cleaned and recharged between shows. But linear polarization requires that users keep their heads aligned with the screen to within 2 percent to prevent ghosting caused by images leaking from one side to the other. Circularly polarized glasses, on the other hand, allows users to tilt their heads as much as 35 degrees without reducing contrast ratio, thereby eliminating ghosting.
ZScreen works by alternatively imparting either clockwise or counterclockwise circular polarization to left and right images, which are sequentially projected. A digital projector equipped with the technology alternatively displays left and right images at six times overspeed, or 144 frames/sec. Because the source video is just 24 frames/sec, each eye receives an image three times per each movie source frame. As a result, the images are perfectly aligned since only a single projector is used.
Moreover, each eye perceives a continuous stream of frames since the gap between them is smaller than the gap between frames of a traditional 24-frames/sec movie.
For future 3DTV systems, however, RealD said it remains agnostic on the format. The company recently release a system that assists developers struggling to standardize on a 3DTV format. Commissioned by the U.S. Navy, RealD's Pod system is a smart HDMI repeater that works between the an HD source and a 3-D display, automatically converting any input formats into the output format for a particular 3-D television.