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Lee De Forest, (August 26, 1873 – June 30, 1961) was an American inventor with over 300 patents to his name. De Forest invented the Audion, a vacuum tube that takes relatively weak electrical signals and amplifies them. De Forest is one of the fathers of the "electronic age," as the Audion helped to usher in the widespread use of electronics.
He was involved in several patent lawsuits (and he spent a fortune from his inventions on legal bills). He had four marriages, several failed companies, was defrauded by business partners, and was once indicted for mail fraud and later acquitted.
Early years
Lee De Forest was born in Iowa to a Congregational minister who hoped that his son would become a minister like himself. His father accepted the position of President of Talladega College (a traditionally Black school) in Alabama where Lee spent most of his youth. Most citizens of the white community resented his father's efforts to educate black students. Nevertheless, Lee De Forest had several friends among the black children of the town.
De Forest went to Mount Hermon School and then enrolled at the Sheffield School of Science at Yale University in 1893. As an inquisitive inventor, he tapped into the electrical system at Yale one evening and completely blacked out the campus, leading to his suspension. However, he was eventually allowed to complete his studies. He paid some of his tuition with income from mechanical and gaming inventions, and received his Bachelor's degree in 1896.
He remained at Yale for graduate studies, and earned his Ph.D. in 1899 with a doctoral dissertation on radio waves.
De Forest was interested in wireless telegraphy which led to his invention of the Audion tube, in 1906, and he developed an improved wireless telegraph receiver. He filed a patent for a two-electrode device for detecting electromagnetic waves. His Audion tube was a vacuum tube which allowed for amplification for radio reception. De Forest said he didn't know why it worked; it just did.
He was a charter member of the Institute of Radio Engineers, the predecessor of the IEEE.
Middle years
De Forest invented the Audion in 1906 by improving the "diode" vacuum tubes being used at the time. In 1907, he filed a patent for a three-electrode version of the Audion. It was later called the De Forest valve, and is known now as a triode. De Forest's innovation was the insertion of a third electrode, the grid or gate, in between the cathode (filament) (or connected to the filament) and the anode (plate) of the previously invented diode. The resulting triode or three-electrode vacuum tube could be used as an amplifier for electrical signals, and, equally important, as a fast (for its time) electronic switching element, later applicable in digital electronics (such as computers). The triode would be a good candidate for the most important innovation in electronics in the first half of the 20th century, between Nikola Tesla's and Guglielmo Marconi's progress in radio in the 1890s and the invention in 1948 of the transistor. The triode version of the Audion was patented (patent number US879532). [1]
The United States District Attorney sued De Forest (in 1913) for fraud on behalf of his shareholders, stating that his claim of regeneration was an "absurd" promise (he was later acquitted). De Forest filed a patent in 1916 that became the cause of a contentious lawsuit with the prolific inventor Edwin Armstrong, whose patent for the regenerative circuit had been issued in 1914. The lawsuit lasted twelve years, winding its way through the appeals process and ending up at the Supreme Court. The Court ruled in favor of De Forest, although the view of most historians is that the judgement was incorrect. In 1916, De Forest, from his own news radio station, broadcast the first radio advertisement (for his own products) and the first presidential election report by radio. He went on to lead the first radio broadcasts of music (featuring opera star Enrico Caruso) and many other events, but could receive little backing.
In the early 1920s, it was reported that he stole the invention of talking movies from Theodore Willard Case, a colleague of his from Yale. In 1922, De Forest improved on the work of German inventors and developed the Phonofilm process. It recorded sound directly onto film as parallel lines. These lines photographically recorded electrical impulses from a microphone, and were translated back into sound waves when projected. This system, which synchronized sound directly onto film, was used to record stage performances (such as in vaudeville), speeches, and musical acts. De Forest established his "De Forest Phonofilm Corporation", but could interest no one in Hollywood in his invention at that time. Several years after the Phonofilm Company folded, Hollywood decided to use a different method but eventually came back to the methods De Forest originally proposed. Even today, when looking in the Encyclopedia Britanica, Lee De Forest is cited as the inventor of sound on film. But it has been speculated that he took these ideas from an old friend.
Later years
De Forest sold one of his radio manufacturing firms to RCA in 1931. In 1934, the courts sided with De Forest against Armstrong (although the technical community did not agree with the courts). De Forest won the court battle, but he lost the battle for public opinion. His peers would not take him seriously as an inventor or trust him as a colleague. For De Forest's initially rejected (but later adopted) movie sound method, he was given an Academy Award (Oscar) in 1959/1960 for "his pioneering inventions which brought sound to the motion picture", and a star on the Hollywood Walk of Fame.
De Forest received the IRE Medal of Honor in 1922, as 'recognition for his invention of the three-electrode amplifier and his other contributions to radio'. In 1946 he received the Edison Medal of the American Institute of Electrical Engineers (AIEE) 'For the profound technical and social consequences of the grid-controlled vacuum tube which he had introduced'.
He died in Hollywood in 1961 and was interred in San Fernando Mission Cemetery in Los Angeles, California.
Patent
External links and references
- deforestradio.com : Dr. Lee De Forest internet radio project & forum
- IEEE History Center Lee De Forest
- National Inventors Hall of Fame's Lee De Forest
- Complete Lee De Forest
- Eugenii Katz's Lee De Forest
- Cole, A. B., "Practical Pointers on the Audion: Sales Manager - De Forest Radio Tel. & Tel. Co.", QST, March, 1916, pages 41-44:
- Hong, Sungook, "A History of the Regeneration Circuit: From Invention to Patent Litigation" University, Seoul, Korea (PDF)
- PBS, "Monkeys"; a film on the Audion operation (QuickTime movie)
This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia Encyclopedia article "Lee DeForest"
