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Light Emitting Diode (LED)

LED or Light Emitting Diode displays were actually precursors of LCDs and if you've been around in the 70s, you'd know them to be cutting edge back then long before the technology of Liquid Crystals Displays or LCDs came about.

And if you've seen those Motel signage's along the road with a series of bulbs to form letters and figures, LED technology does the same with miniature semiconductor devices called diodes that emit light arrayed to form letters and numbers as well as basic figures on a display. Early so-called digital watches had them for displays as it's fairly easy to have them form the numbers of a watch. Many modern devices still use them like bundy clocks and door security systems as well as running signage's in airports.

Liquid Crystal Display (LCD)

On the other hand Liquid Crystal Displays or LCDs is a landmark in digital display which, as the name indicates, use a substrate liquid crystal sandwiched in polarizing layers that variously excite individual crystal molecules acting as pixels to from images when electric current is applied.

Today, we have brands like Sony, Samsung and Panasonic advertise better LCD flat TVs with LED technologies. But what has LEDs got to do with LCDs? It's all about backlighting. The high resolution images that LCDs can deliver mean nothing since you won't see any of that without backlighting. LCD screens require a special fluorescent light called CCFL to illuminate the screen from behind, hence the name.

The problem with this conventional LCD backlighting is that it lights up the entire screen uniformly all the time so you can never have really deep blacks. With all the lights in a room turned off, this gets obvious as an LCD screen turned on without any images glows. A really great screen should not glow at all in the dark with no images.

There's really no such thing as LED TV. The correct reference to the new generation of LCDs using LED backlighting is LED-Backlit LCDs. But those are three words too long for the consumer to remember. It doesn't matter that an LED TV is a misnomer, as 21st century home theater enthusiasts can get the idea.

LED backlighting comes in two modes. One uses a uniform clustering of LEDs behind the LCD layer called a Direct or Full LED backlighting. The system uses about 200+ LEDs spread uniformly behind the LCD active layer to throw light directly on the screen area that needs to be lighted and are turned off in various levels when displaying dark areas, hence, the name. Depending on the screen size, there could be twice as much.

The other mode uses a more affordable set of LEDs arranged along the display sides to throw light across the screen and is referred to as Edge LED backlighting. This backlighting mode is generally less accurate, exhibit lower contrast ratio and cheaper to produce. But LCD models using them allow for more aesthetically slimmer LCD flat panels as well as more efficient power consumption compared with direct LED backlighting. In addition, they don't suffer the "halo" effect in direct LEDs.

Some brands prefer one over the other while some have models on both. For sure, consumer electronic brands are racing against each other with new technology refinements to overcome their inherent shortcomings as LED backlighting is relatively new in the display wizardry department. We expect to see better models in the next few years, as always.

Plasma displays remain supreme in terms of color definition and contrast ratio. That's because there's no backlighting as each pixel carries its own illuminating property to display images when they have to and are turned off in black areas so you get true blacks at the pixel level.

So-called LED TVs can only approximate this ability with a separate processing engine to control selective backlighting. They can never have the precision of Plasma blacks but smaller LEDs in clusters can trick the eye to see better contrasts. The one edge that LCDs have over Plasmas is image sharpness and definition.

Plasmas are more generous at dithering edge information so that images are softer which is why they are preferred in video sources using upscaling of lower resolution DVDs. Plasmas are more forgiving on video artifacts and pixilation present in upscaled low resolution sources. On the other hand, LCDs are more accurate in displaying exactly your source, crappy or not.

Seeing the advantage of LED-backlit LCDs, consumers have started to flock to models offering either mode as they are superior to conventional LCDs made earlier than 2009 when they first appeared. The prices are still high, of course, but if you are looking for better contrast ratios on images that are sharper than on Plasma TVs, it's a no brainer. LED TVs win hands down.

At this time, LED backlighting LCDs are offered in a wide array of choices among the industry giants like Samsung and Panasonic. 32-inch LCD panels have been the most popular, followed by 42-inchers with prices that have seen dramatic reductions over the last couple of years thanks to the economies of scale. LED backlighted sets may have created a new product cycle to bring the price up but expect them to go down further by next year.

Size matters. And in no area of leisure activity does it matters more than in home theaters. To many people, room size is the limiting factor. But that is an old perception prompted by the older CRT television sets that require at least 3-times the screen size as your minimum viewing distance.

Flicker and radiation common in CRTs that cause eye strain do not exist in LCD panels. It should interest you to know that in Tokyo City where average city living spaces are cramped, residents can hang a 52-inch flat panel display in a room averaging about 9-12 square meters. With a viewing distance that's no farther than 4-5 feet away, the visual experience on such a large screen can literally blow you away watching a blockbuster movie with enveloping multichannel sound.

That's really what high definition video is all about - watching glorious images with coffee table book quality up close. You can never do that with CRT TVs where the pixels on screen sizes above 25-inches become obvious at 4-5 feet away. With fine LCD displays, those pixels can't be seen at those distances even on 52-inch screens. So forget about room size as a limiting factor to enjoying the best flat panel TVs.

With LED backlighted LCDs, you can now enjoy the best video watching experience until the next new technology comes along. Size would be dictated by your wallet, not your room size. For the average American homes with a larger living space, you can't go wrong getting the largest LED TV you can afford.