An imaging device consisting of a vacuum tube, in which an electron beam is swept across a phosphor coating on the glass where the image is focused, and its electrical potential varies in proportion to the level of light it encounters. This varying potential becomes the basis of the video signal produced.
(from the article `television`) ...in 1924 and by Philo T. Farnsworth (the Image Dissector) in 1927. These early inventions were soon succeeded by a series of improved tubes such as ...
a photoconductive camera tube in which the electron image is stored on the photoconductive surface and scanned by an electron beam, usually of low-velocity electronsa low-electron-velocity camera tube with a photo-conductive layer based on antimony sulphide