LED TV’s  are technically a member of the LCD TV family. The display screen on a LED is a liquid crystal display the same as it is on any other LCD TV. The main difference between the two lies with different backlighting techniques which may change the picture quality characteristics dramatically.

Traditional LCDs have used some form of flourescent lighting from tubes to much more advanced flat arrays of lights. LED TVs use Light Emitting Diodes to light the LCD panel. Just as there are different styles of flourescent lights in traditional LCDs there are also different styles of LED backlighting.

Traditional LCD televisions always have their backlight on when the TV is on. To create black or dark areas the screen must block the light by twisting the crystals to a closed position, often resulting in a lower contrast and less detail in dark areas of the picture. This is a shortcoming in LCD technology that LED TVs with local dimming are attempting to correct. With the controlled backlighting the LEDs can be dimmed in dark areas of the picture to create darker blacks and better detail in dark scenes.

ADVANTAGE: Local dimming LED TV technology has a clear advantage in contrast and black levels.

While traditional LCDs have improved their useable viewing angles over the years this is still a shortcoming of the technology itself and even the best LCDs will suffer from contrast degradation when viewed from angles wider than around 30 degrees off center. The LED backlit LCDs we've seen have done a fantastic job of correcting this issue and have viewing angles that rival plasma TVs (but at a much higher price).