Iconoscope, << y KON uh skohp, >> was one of the first devices capable of converting light images into electric signals that could be used to produce a television image. It was invented in 1923 by the Soviet-born physicist and electronics engineer Vladimir K. Zworykin. The iconoscope helped lead to the development of early television cameras. It has since been replaced by smaller, more sensitive forms of light-sensitive technology.
An iconoscope includes an insulating plate inside a large vacuum tube. The insulating plate consists of a metal plate on one side and many small silver globules (tiny drops) on the other. When light passes through a window in the vacuum tube and strikes the silver globules, the globules become electrically charged. The charge is greater where the light is bright than where the light is dim.
The vacuum tube also has an electron gun. This device directs a stream of electrons at the charged silver globules. The electron beam removes the charge from the globules and produces an electric signal on the metal plate opposite them. Stronger electric signals are produced when the electron beam strikes globules that have a greater charge. Some older television displays operated by converting the electric signals from an iconoscope into a screen image.
