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LED HDTVs Explained

By now, you've probably seen advertisements for LED HDTVs and the great picture and slim size they offer. So is LED a completely new type of HDTV?

An LED HDTV is a type of LCD HDTV

LCD stands for "liquid-crystal display," a thin, flat panel that can display information for everything from clocks and calculators to laptops and HDTVs.

To create lighting for televised images, all LCD HDTVs need backlights behind their display panels. Until recently, most LCD HDTVs used a type of fluorescent backlighting, but an increasing number are now using LED (light-emitting diode) backlighting instead.

This means that an LED HDTV is not a new type of television, but a new type of LCD HDTV.

There are two main ways to backlight an LED HDTV

While an LED HDTV is simply an LCD HDTV with LED backlighting, there is more than one way to create that backlighting:

Two main ways to backlight an LED HDTV

Local dimming:
These HDTVs have lights behind the full length and width of the display panel. The lights then brighten, dim or turn off independently, depending on the picture displayed. This allows for deep blacks that can rival plasma HDTVs. On some sets, however, local dimming can create a bit of bleeding of brighter areas into darker areas, which can lighten the black level somewhat.

Edge lighting:
These HDTVs have lights only along the edge of the screen. The light produced is projected inwards towards the middle of the display panel. The big advantage is that edge lighting allows for extremely thin cabinets/panels. However, the lighting isn't always as uniform as with local dimming.

LED backlighting can produce deeper blacks than conventional LCD HDTVs

Plasma HDTVs are generally recognized as producing deeper blacks than LCD HDTVs, but LED backlighting goes a long way towards closing that gap. Within LED HDTVs, those with local dimming appear to offer the deepest blacks.

LED HDTVs are energy efficient

LCD HDTVs are known for using a low amount of energy, and LED HDTVs can take that an extra step. All Samsung LED HDTVs, for example, use up to 40% less power than conventional Samsung LCD HDTVs1.

The LED HDTV picture is not ideal when viewed from the side

One traditional disadvantage for LCD HDTVs when compared with plasma HDTVs is that the LCD picture degrades more when viewed from the side. This remains an issue with LED HDTVs.

OLED is different from LED

You may have an OLED (organic light-emitting diode) display for your MP3 player or other portable device, but the technology is not the same as LED. OLED display devices don't require backlighting, as they emit light themselves. OLED technology has not yet made its way into mainstream HDTV production.

1As compared to 2008 similar size class Samsung LCD TVs in standard mode.