Past Forward: The Mechanical TV

Abstract

In 1885, German engineer Paul Nipkow patented the idea of capturing and transmitting a picture by dividing it into lines, using a spinning disk with a spiral of perforated holes to scan the lines. The lines were turned into electrical signals, and a receiver then turned the signals back into light. Nipkow never commercialized his “electric telescope,” but decades later, Scottish inventor John Logie Baird took the idea much further. Baird's electromechanical system transmitted images using a spinning Nipkow disk fitted with glass lenses and a photoelectric cell. A companion Nipkow disk in the receiver re-created the lines of the image and projected them onto 26 January 1926, select members of the Royal Institution gathered at Baird's lab in London to witness the transmission of a small but clearly defined image of a ventriloquist dummy's face. The event is often heralded as the first public demonstration of television.