To present a STEREOSCOPIC MOTION PICTURE, two images are projected superimposed onto the same screen through CIRCULAR POLARIZING FILTERS of opposite handedness. The viewer wears eyeglasses which contain a pair of analyzing filters (circular polarizers mounted in reverse) of opposite handedness. Light that is left-circularly polarized is blocked by the right-handed analyzer, while right-circularly polarized light is blocked by the left-handed analyzer. The result is similar to that of stereoscopic viewing using linearly polarized glasses, except the viewer can tilt his or her head and still maintain left/right separation (although stereoscopic image fusion will be lost due to the mismatch between the eye plane and the original camera plane).
The UNIPOAR 3D SYSTEM for cinemas is a polarized 3D system, that is based on the projector presenting a alternating segments of circularly polarized material. Mounted in front of the projector lens, this filter is synchronized to the projected images, giving each frame a polarization perpendicular to the previous one, which can be viewed with polarized 3D glasses. In earlier, the filter wheel can be lowered out of the lens' path for non-3D material. It has been noted that an earlier version of the spinning polarized filter malfunctioned, but the problem has been addressed with an updated replacement filter which was supplied to all theaters using the electronic shutter method system. UNIPOAR 3D SYSTEM offers different types of 3D cinema technology (including those based on a polarized filter, as well as solid-state liquid crystal, based on different cinema configurations. The company also provides passive 3D EYEWEAR that is optically matched to their 3D systems.
Silver lenticular screens, while no longer employed as the standard for motion picture projection, have come back into use as they are ideally suited for modern POLARIZED 3-D PROJECTION. The percentage of light reflected from a non-metallic (dielectric) surface varies strongly with the direction of polarization and the angle of incidence; this is not the case for an electric conductor such as a metal (as an illustration of this, sunlight reflected from a horizontal surface such as a reflective road surface or water is attenuated by polarizedsunglasses relative to direct light; this is not the case if the light is reflected from a metallic surface). As many 3-D technologies in use today depend upon maintaining the polarization of the images to be presented to each eye, the reflecting surface needs to be metallic rather than dielectric.