As early as 1829, Joseph Prado, a famous Belgian physicist, found that when an object disappears from people's eyes, the image of the object will remain in people's retina for a period of time. This discovery is called "the principle of visual persistence". According to this principle, Prado invented the "magic disc" in 1832. The "special tray" can make the picture drawn on the zigzag cardboard box move because of the movement, and can also make the generated moving picture visually decompose into various images. The appearance of the "mysterious disc" indicates that the invention of the film has entered the stage of scientific experiment. 1834, the experiment of "removable video disc" in Halner, USA was successful; 1853, on the basis of the above invention, Austrian general Von Uchetios showed the original cartoon with a slide show.