Nipkow disk

Paul Nipkow's patent, 1884 Every television picture since has been built the way this idea proposed: break the scene into lines, send them one after another, rebuild them fast enough that the eye sees a whole. Nipkow's disk did it with a spiral of holes, each one sweeping a strip of the image past a light-sensitive cell, with a matching disk at the receiver. His German patent was granted in January 1885, backdated to January 1884, and it is not known whether he ever tried to build one. The idea waited decades for workable hardware, and in the 1920s and 1930s hundreds of experimental stations used it.