This video traces the remarkable journey of display technology from 1940 to 2020. Starting with the bulky cathode-ray tube ...

Roentgen noticed that an unidentified ray was escaping from beneath the black cardboard covering his cathode tube, causing a nearby fluorescent screen painted with barium platinocyanide to glow green.

Röntgen was originally trying to find out whether cathode light rays - invisible streams of electrons, that could only be seen in glass vacuum tubes - could ... of the x-ray we know today.