imageorthicon

The image orthicon was a type of camera tube used for television broadcasting from the late 1940s into the 1960s. It was a vacuum tube that converted a light image into an electronic signal. The tube contained a photosensitive mosaic target and an electron gun that scanned the target. Light striking the mosaic caused it to develop a positive charge in proportion to the light intensity. The electron beam, traveling in the opposite direction, struck the back of the target and reflected off. The reflected beam's intensity varied based on the charge on the mosaic, creating the video signal.

The image orthicon was a significant advancement over earlier camera tubes like the iconoscope, offering much greater sensitivity and a wider dynamic range. This allowed for better picture quality, especially in dimly lit conditions. Its ability to capture subtle gradations of light and shadow made it the standard for live television production for many years. However, it also had drawbacks, including image lag and susceptibility to "sticking" if bright highlights were held on the screen for too long. The development of the vidicon and later solid-state camera sensors eventually led to the image orthicon's obsolescence in broadcasting.