Optical prism

The optical prism technique is used in some 3D screens. In this technique, a network of filters is placed in front of the screen, the pitch of the filters being equal to the width of one pixel or half a pixel. These filters modify the angle at which points of the image are seen. Thus, provided the viewer is at the right distance, they see two images simultaneously, the left eye seeing the pixels of one image and the right eye the pixels of the other; the image then appears in relief.