Transmitting portion of Baird's television apparatus, 1926.
© Science Museum / Science & Society Picture Library
John Logie Baird (1888-1946) used this large spinning cardboard disc containing 30 lenses in a spiral, to scan a puppet called Stookie Bill. As the disc rotated, each of the lenses scanned a different part of the subject. This idea was first suggested by the German physicist Paul Nipkow (1860-1940) in 1884. His 'Elektrisches Teleskopdisc' used reflected light from a subject to stimulate a photo-sensitive selenium cell, producing an electric current which charged a light source in a receiver. The result was a flickering reproduction of the transmitted image. During 1929-1935, the BBC transmitted experimental Television using Baird's system; a year later the world's first regular high definition television service began.