Simply put, an LED television and an LCD television are one and the same thing. The difference between a standard LCD television and an LED model lies in the method of backlighting. Normal LCD screens are built by sealing a layer of liquid crystal in between two glass panels. Behind this are a series of Cold Cathode Fluorescent Lamps - CCFL - that project light through the crystal polymer. When a controlled current is run through the crystals, they either add colour to the light, or block it out completely. In LED televisions, the CCFL lighting is replaced by a sequence of LEDs. As they are much smaller than CCFL lights, televisions that are LED-backlit can be made much thinner and lighter than regular LCD models. Some are even under an inch thick! LED televisions are also capable of greatly increased dynamic contrast - the ratio of difference between black and white - use less power, and are more environmentally friendly when disposed of.
However, the differences don't end here. Currently there are two commonly used methods of LED backlighting, known as Edge LEDs and RGB Dynamic. Each has advantages and drawbacks, so if you're thinking of buying an LCD television, it's good to know what each method has to offer. In RGB Dynamic models, a sequence of red, green and blue LED lights are positioned behind the screen. When an image is displayed featuring dark colours, the LEDs in that area are dimmed while the intensity of the colour is increased. As a result, televisions with RGB Dynamic backlighting have higher Dynamic Contrast ratios than any other LCD model, although they are still second to plasma technology when it comes to 'true' blacks. The downside of this method is a loss of fine detail on small, bright objects that appear against a dark background - an image of a night sky is a good example.
By contrast, the Edge LED method is a completely different kettle of fish. This type of backlighting involves the placement of white LED lights around the outside edge of the screen. A light-diffusing panel is then placed behind the screen, which compensates for the lack of light coming from the centre. Edge LED backlighting is not capable of the same Dynamic Contrast ratios offered by the RGB Dynamic method, because it can't dim the backlight as precisely in a localised area. However, it is the cheaper of the two methods, and televisions carrying this technology are some of the thinnest and lightest on the market, making them extremely easy to wall mount.
So there you have it - there are pros and cons to LED backlighting, just as there are pros and cons to LCD and plasma flat screen TVs
Written by Jake Reacher, he is a great fan of flat screen TVs, and judging by his massive Blu-ray disc collection, likes his TV HD -style! There's not much this man doesn't know about flat screen technology.
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