When I first read about LED TVs years ago, my understanding of how they work is this...
Rather than having a backlight that lights up the pixels, each pixel is its own LED that shows whatever colour is needed, and if the pixel is meant to be black, then the pixel just turns off. This meant two things:
1. That there is an electricity saving to be had from the fact that there is no backlight and that not all pixels are on all the time.
2. That due to there being no backlight to pollute light, the black parts of the screen are actually black, because the pixel LEDs are turned off - a darker black that what TVs have been able to manage before
When I read the above, it made perfect sense to me. However, I've seen a few LED TVs since then, and they all have backlight, and the 'black' that they show is no more black than any other TV.
What's going on?