parallaxbarrières

Parallax barriers are a form of autostereoscopic display technology that enables three-dimensional viewing without the need for special glasses. The system uses a thin opaque mask with a pattern of alternating transparent slits placed in front of a two-dimensional display. The slits are aligned with the display's pixel grid so that each eye sees a different subset of pixels, allowing the brain to fuse two slightly offset images into a impression of depth.

In operation, two images are prepared for the left and right eye. The barrier directs the light so that the left eye predominantly receives the left-eye image and the right eye receives the right-eye image. Because the alignment between the barrier, the display, and the viewer determines which pixels are visible to which eye, the effect is strongest within a specific viewing region. Vertical slits are the most common arrangement, though horizontal or more complex layouts have been explored to alter viewing geometry.

Advantages of parallax barriers include the ability to deliver glasses-free 3D at relatively low cost and with simple construction. They require no motion tracking or additional optics beyond the mask. Disadvantages include a limited viewing angle and viewing position sensitivity, reduced effective horizontal resolution since each eye sees only a portion of the pixels, and potential crosstalk or ghosting if the alignment is imperfect or the viewer moves.

Parallax barriers have been employed in early and specialized autostereoscopic displays, including some portable devices and signage. They are often compared with lenticular lens approaches, which can offer wider viewing zones but tend to be more expensive or complex to manufacture.