Spectacles used for viewing 3D films have –

A polarized 3D system uses polarization glasses to create the illusion of three-dimensionalimagesbyrestrictingthelight that reaches each eye, an example of stereoscopy.Topresentstereoscopicimagesand films, two images are projected superimposed ontothesamescreenordisplaythroughdifferent polarizing filters. The viewer wears low-cost eyeglasses which contain a pair of different polarizingfilters. As each filterpasses onlythat lightwhichissimilarlypolarizedandblocksthe light polarized in the opposite direction, each eye sees a different image.