Parallax Barrier

Parallax barriers are a glasses-free 3D display technology that uses a precisely aligned slatted barrier (similar to a window blind) placed in front of an LCD screen. The barrier blocks specific pixels from reaching each eye, creating binocular disparity and a stereoscopic effect.

They have many advantages like their simple design, low cost, and perfect compatibility with existing LCD panels. However, their disadvantages are the reduced brightness, limited viewing angles, and lower resolution.

Parallax barriers have been used with eye-tracking to adjust the pixel rendeirng relative to the position of the pixels, barrier slits and user's eyes, allowing the user to experience the 3D from a wider range of positions

Used in early Nintendo 3DS and some autostereoscopic signage, though largely replaced by lenticular lenses in modern displays due to better light efficiency.

Parallax barriers are a common technique used to divide the content shown in the display, for example, the navigation system in teh 2010-model of Range Rover used parallax barriers to show one view to the driver and a diferent one to the passenger.