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Technology ---> TV ---> LED-LCD 

 

Often referred to as simply "LED TVs", these HDTVs are actually LCDs that use LED backlighting. Think of them as the next-generation LCD screen. 

 

 

 

How it works:

Since LEDs are still LCDs, we'll just discuss the LED technology used on these displays (For more info on how LCDs in general work, see LCD Technology). Now, there are two types of LED setups. Some LCD TVs use LEDs only along the sides of the screen. This is called an "edge-lit" system. For the more expensive models, the manufacturers will go all-out and use LEDs for the entire backlighting system. 

 

55" Samsung 3D LED-LCD UN55C7000

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Some of you are probably wondering, why use LEDs in the first place? On standard LCDs, fluorescent tubes for the backlighting system, (hence the name CCFL, or Cold Cathode Fluorescent Lamp). While this creates a very bright picture, the one disadvantage that most of these LCDs have compared to Plasma is their inability to correctly display deep black levels. The fluorescent tubes, which are always on, tend to "leak" light through the screen, which creates that bluish glow that you see during dark scenes. LEDs, however, can be turned either on or off individually, allowing the screen to create deep black levels in the needed areas.

 

Now, there are two main types of LED backlight configurations. The simplest method is to place LEDs around the edge of the screen. This "edge-LED" technique not only removes the glowing effect around the edges of an LCD screen, but also allows for a very thin screen. The other method is to use LEDs for the entire backlighting system. This method, known as "Dynamic RGB LED lighting", is more effective as it allows for "local dimming" on specific areas on the screen. This results in an even higher contrast ratio compared to models which only use edge-lighting. Samsung LED models use edge lighting, where as Sony LED models use the Dynamic RGB setup. However, Samsung's LED models compensate for the lack of a full-LED layout by using Samsung's True Black screen, which alone greatly increases black levels compared to other models, but with the addition of screen glare.

 

Advantages:

High contrast ratio

LEDs are significantly brighter than fluorescent tubes, which means that they not only create deeper blacks when turned off, but also create whiter whites when turned on. This results in a greatly increased contrast ratio compared to traditional CCFL LCDs.

 

More efficient and Green

Going with an LED LCD not only gives you more eye candy, it'll also save you some cash in the long run. LEDs are much efficient, using about 40% less energy than the typical CCFL LCD, when compared to a model of the same size. Unlike the fluorescent lamps, LEDs use no mercury, which means that they're much more environmentally friendly, too. However, they are produced with gallium and arsenic.

 

Thinner displays

LEDs are incredibly small, which means that they require very little space for placement. This allows LED-LCDs to be designed with a much slimmer profile. For examples, current Samsung LED models are as thin as 1.2".

 

Disadvantages:

Expensive

The only drawback to LED-lighted models over traditional LCDs is their significantly higher price compared to traditional LCDs. For example, Samsung's 55" LCD model LN55B650 retails for $2099, compared to their entry level LED TV model UN55B6000, which retails for $3299. Expect these prices to drop, however, and LED-lit TVs increase in popularity.

 

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