3D television display. French inventor Pierre Allio holding up the screen used in his glasses- free 3D viewing system. Called alioscopy, the system is similar to other 3D displays in that it uses two overlapping images to make the brain see a three-dimensional image. Instead of glasses being used to view the results, the optical part of the system is the television screen. Seen through the screen, the two images are combined, forming the desired 3D effect. The images on the screen appear to extend outwards towards the viewer.