Thomas Alva Edison (1847-1931), US inventor, in his laboratory at East Orange, New Jersey, USA. Edison is famous for inventing or improving devices such as the phonograph and the electric light bulb. Edison was one of the first inventors to build research laboratories to make and develop inventions. He also founded several companies, and filed over 1000 patents. Other work included improvements to telegraphy, cameras, and motion picture cameras, as well as promoting his DC electrical distribution systems. He also discovered the Edison Effect, on which thermionic valves are based. Photographed circa 1901.