Lee De Forest

In 1906, Lee De Forest invented the Audion triode vacuum tube, a device that could amplify weak electrical signals. He achieved this by adding a third electrode, known as a grid, to an existing Fleming valve. This innovation became the foundational technology for all long-distance radio and telephone communications.

De Forest significantly advanced the film industry by inventing the Phonofilm system in the early 1920s. This was one of the first optical sound-on-film technologies, allowing audio to be recorded directly onto the edge of the movie strip. Although commercially surpassed by Vitaphone, it paved the way for the 'talkies.'

Yes, De Forest was famously sued by Edwin Armstrong over patent rights to the regenerative circuit. Though De Forest ultimately won the patent in a Supreme Court decision, the engineering community widely acknowledged Armstrong as the true inventor. The legal battle is considered one of the most famous and controversial patent disputes in radio history.

In 1902, De Forest founded the De Forest Wireless Telegraph Company to commercialize his early radio equipment. He later established the De Forest Radio Telephone and Telegraph Company to push his Audion technology. These companies heavily promoted public demonstrations of wireless communication, though they often struggled financially.