Pair of Polaroid polarised glasses for 3D cinema in original case, 1960-1970.
A polarized 3D system uses polarisation glasses to create the illusion of three-dimensional images by restricting the light that reaches each eye (an example of stereoscopy).
To present stereoscopic images and films, two images are projected superimposed onto the same screen or display through different polarizing filters. The viewer wears glasses which contain a pair of different polarising filters. As each filter passes only that light which is similarly polarized and blocks the light polarized in the opposite direction, each eye sees a different image. This is used to produce a three-dimensional effect by projecting the same scene into both eyes, but depicted from slightly different perspectives. Multiple people can view the stereoscopic images at the same time.