As Norm says both types of sets use an LCD panel but the difference is in the backlight only.
The older original models use a CFL tube for backlight while the newer LED models backlight with LED's instead.
It remains to be seen really which will provide better life?
I have seen a lot more panels with LED have a few die than CFL where the tube itself would have to die.
Since CFL tubes are also a higher color temperature than normal movie studio lighting
and trend to the blue end of the color spectrum the LED which also trend to bluish were an ideal replacement when they were first used for this.
We will see?