Let's hope we just stick to black screens to save some power and prevent burn-in at the same time.

Why didn't we do this back in the CRT era, and invented screensaver instead, then? TV is understandable, you don't want a DVD player to show a black screen, otherwise it appears dead. But what about screensavers on computers, why did it come into being? (I know turning a CRT on takes time, but we don't have to turn it off completely to blank the screen either?)

Update: It appears that the original motivation was public terminals/machines.

There is something to say for knowing that the device is on. Saves you from accidentally turning the device off when you wanted to turn it on.

Spinning up and down a CRT reduced its life-span, I wager.

I don't think it was a major concern. First, you can always display a dummy black image without turning off the CRT. Also, VESA defines two "off" modes in DPMS (1993): blank and fully off. "Blank" allows the monitor to partially suspend without shutting down the CRT completely, which allows an instant recovery.

Might as well have an animation, as opposed to "black light"?

> as opposed to "black light"

BTW, the "black" on a CRT is almost a true black. The electron beam is off when the signal voltage is less/equal to the black level, there's no "black light" if the black level is perfectly calibrated. Displaying a black image fullscreen is indistinguishable from an endless vertical/horizontal blanking interval from a practical standpoint. There's a measurable decrease in power consumption, although it's not much (it can be great enough on a large TV, though).

On the other hand, VESA blanking mode turns off additional circuitry, and it can save a lot of power while still keeping the CRT heater on, suspending the screen without the disadvantages of a long wakeup time or stressing the tube.

Actually it was Plasma that did that a long time before OLED.

But hey, raytraced !