The Rise and Fall of the Plasma Screen
8th October 2026
In 1960, a team at the University of Illinois released the first version of their PLATO “computerized instruction system,” a network of what would eventually be thousands of computer terminals connected to large mainframe computers. Users of PLATO could use the system to learn about various topics, with courses on subjects such as chemistry, math, music, and foreign languages.
I remember PLATO from my years in graduate school at Indiana University. It raised expectations that have even now not yet been fulfilled.
The first iteration of PLATO used a simple TV screen for a terminal display, but this was at best a stopgap measure. TV screens used cathode ray tubes (CRTs), which used a magnetically deflected beam of electrons to paint an image on a glass screen. This beam redrew the entire screen 30 times a second, which meant that a computer had to feed the CRT screen a constant stream of high-bandwidth video data. This was fine for broadcast TV, since the same signal was being sent to every TV that received it, but on the PLATO system every terminal needed to be sent different data, depending on what the user was doing. Not only would this require high-bandwidth data connections between the mainframes and the PLATO terminals, it would force each terminal to have a large amount of memory storage to hold the video data, which at the time was extremely expensive. CRT-based screens worked well enough for a small system with a few terminals, but it was felt that the technology wouldn’t scale to the thousands or millions of terminals the PLATO designers envisioned. What was needed was a new type of screen, one that had a built-in “memory.” On such a screen, only the things that changed on the screen would need to be redrawn, which would dramatically reduce the bandwidth and data storage such a screen required compared to a CRT.
The change in personal computers from escape-code text to memory-mapped video was a major advance.
Donald Bitzer, one of the architects of the PLATO system, considered possible methods that might be used to make such a display. One potential option was gas plasma — running an electric current through a low-pressure gas, which would cause that gas to glow. Scientists had been making low-pressure gases glow using electric current since the 1600s, and the phenomenon had been used in neon signs since the early 20th century. But no one had yet found a way to turn the phenomenon into a computer display, which would require an array of thousands or even millions of independently controlled tiny gas plasma lamps, one for each pixel on the screen. Bitzer decided it was worth trying.
I lusted in my heart for a Grid Compass when I was younger. Ah, those were the days.