by francopoli

Farnsworth worked out the principle of the image dissector in the summer of 1921, not long before his fifteenth birthday, and demonstrated the first working version on September 7, 1927, having turned 21 the previous August. A farm boy, his inspiration for scanning an image as series of lines came from the back-and-forth motion used to plow a field. In the course of a patent interference suit brought by RCA in 1934 and decided in February 1935, his high school chemistry teacher, Justin Tolman, produced a sketch he had made of a blackboard drawing Farnsworth had shown him in spring 1922. Farnsworth won the suit; RCA appealed the decision in 1936 and lost. Although Farnsworth was paid royalties by RCA, he never became wealthy. The video camera tube that evolved from the combined work of Farnsworth, Zworykin and many others was used in all television cameras until the late 20th century, when alternate technologies such as charge-coupled devices started to appear.