I believe its determined by the pixals or dots of the Tv. It's like when they tell you its 1080I. Simular to a computer screen, I think. I do know that no matter how expensive or if you get the best TV made that if your reception or signal strength isn't good you won't have a good picture.
Both of them are very similar to me. LCD or TFT has pixels but flat Screen or other T.V's have picture tubes so both have pictures tubes. What's the difference then?
Flat screen or flat panel are just names given to describe the viewing surface of a television or monitor. CRT type televisions used to have mainly a curved viewing surface. As televisions began to evolve before high definition became fashionable, manufacturers began making them with a flat viewing surface. Hence, the name, flat screen or flat panel.