Forget your LCDs and plasma screens: the device that made television the universally popular medium it is today was the cathode ray tube.
A “cathode” is a heated filament housed in a vacuum inside a glass tube. The “ray” is a stream of electrons that pours off the heated cathode into the vacuum and hits the flat screen at the other end of the tube. The phosphor on this screen glows when the beam of electrons strikes it. Organise the beams a bit, and you’ve got a moving television picture. (That’s the tech in a nutshell.)
The thing you need to know, though, is that before all this liquid-crystal-display wizardry in our living rooms today, all of our television sets relied on CRTs.
From the first commercial televisions of the 1920s right through to the early years of the 21st century, CRTs were the only technology we had.
The tube had to be strong enough to maintain the vacuum and keep out the air. The tube also had to be glass for the beams to hit the phosphor. The tube therefore had to be made of very thick glass. Our TV sets were thus both ENORMOUS and wearyingly heavy.
When the flat-panel screens came in, consumers were delighted. Televisions became lighter, and you could mount the screen on a wall. (Try doing that with a cathode ray tube.)
The CRT was a foot-soldier for over 80 years in the march of entertainment progress but few of us mourn their passing. They were difficult and dangerous to recycle, they took up enormous amounts of floor space, and you couldn’t entirely rely on them not to explode.
Still, let’s take a moment to salute the TV that was so versatile it could not only display pictures but store your punch bowl and all its cups at the same time. (This doesn’t seem entirely practical to me but, as you can see in the photo below, which I took earlier this year at Graceland, it’s exactly what Elvis did. So it can’t be wrong.)