A type of glasses-free 3D (autostereoscopic) technology that separates the image into columns of left and right pixels and uses an opaque barrier layer with vertical slits to direct the eyes appropriately. Dating back to the early 20th century, various parallax methods have been employed on cameras and other devices, some of which were very short lived. In 2009, Hitachi introduced mobile phones in Japan with parallax screens, and two years later, Nintendo launched its parallax-based 3DS game console in the U.S. Although the barrier layer may be adjusted by the user, this method is more adaptable to phones and video games where the user's head remains in a fixed position when viewing the screen. See lenticular 3D, 3D visualization and 3D rendering.