Farnsworth accomplished much in his lifetime, despite seemingly endless fights in patent court. The whole story is beyond the scope of this article (but is readily available). Here, I will focus on a few interesting points.
A stack of popular science magazines in the attic of their new home helped Philo learn more about electricity and electro-mechanical devices. Primitive “tele-vision” – distant transmission/viewing of images – was one of the fascinating topics of the day.
with his former high school teacher.
Philo T. Farnsworth Archives.
By the time he entered Rigby High School, Philo had already exhibited a firm grasp of practical physics, especially electrical phenomena. As the story goes, he devised a better way to record images for transmission while plowing a field in regular back-and-forth rows (lines). However, the complete account involves rather more than that simple idea.
His science teacher at Rigby High School, Justin Tolman, soon recognized the young man’s aptitude and encouraged his pursuit of knowledge. It was he who first learned of Philo’s new approach.
Back then, typical television “cameras” employed a mechanically rotating array of mirrors to focus snippets of an image onto a photocell, which converts photons (light) into flowing electrons … electricity. Without going into all the physics, the electrical response shows how bright the light is. The electrical signal is then transmitted through some distance to a display system. Since Philo’s innovation involved the recorder, not the display, we’ll simply take the viewer as a given.
Mechanical cameras are bulky and require a high degree of precision in their manufacture. In operation, they tend to be noisy, and dust, wear, or mechanical malfunctions hopelessly cripple the synchronization between recorder and display.
|Farnsworth’s conceptual sketch. Philo T. Farnsworth Archives.|
Farnsworth’s accomplishment was to devise a way to electronically record the picture. His innovation combined several crucial features. Instead of directing snippets of light onto a small photocell, the camera captured the entire picture on a plate coated with photosensitive material. He placed this photosensor inside a vacuum-sealed cylinder, so the electrons generated flew off (were emitted) into empty space.
Philo's device then focused the electrons emitted from a small region – we now call it a pixel – onto an electrode that measured the electrical signal. A simple controller selected pixels one after another to form a line of dots crossing the photosensor horizontally. As in the plowed-field analogy, a series of parallel dot-lines growing from top to bottom covered the entire screen.
Because the device operated electromagnetically – no moving parts at all – the entire picture could be recorded many times each second … and “electronic” television was born.
Ideas similar to Farnsworth’s design had been considered by others, but he was the one who put all the pieces together, and made it work. He passed away in March 1971. Today, the city of Rigby bills itself as the “birthplace of television,” and sponsors the Farnsworth TV & Pioneer Museum.
|Richard J. Beck, Famous Idahoans, Williams Printing, (© Richard J. Beck, 1989).|
|Donald G. Godfrey, Philo T. Farnsworth: the Father of Television, University of Utah Press (2001).|