LED TV Buying Guide

LED TV is another form of LCD TV that uses LED to provide light source. All LCD TVs are back-lit because LCDs are a transmissive type of TV display technology, which means that they don't produce their own light. For LCD television to produce an image, its pixels have to be back-lit by a separate lighting source. Currently, most LCD TVs used CCFL technology or cold cathode fluorescent lamps as their light source. They deliver good colors and brightness, and decent contrast, but not great blacks - the domain of the plasma TV.

But TVs utilizing brighter LED back-lighting can achieve much better blacks, as well as brighter colors and even greater contrast ratios. But just in case you thought your selection choice was now made easy, there are a couple of LED options - full matrix LED and edge lit LED TVs. Let's go through the differences and look at what some of the manufacturers are using as their preferred back-lighting choice.

A true LED TV is one of those giant screens you usually see at outdoor stadiums, at grand prix events and rock venues. They are large screens made up of thousands of extremely bright LED lights. But because the size of LEDs are mostly too big and chunky to use in TVs, but they are an ideally suited as a light source for backlighting LCD crystals.

How LED technology is used in LCD TVs

Edge lighting: it is pretty much as described. In this method, a series of LED back-lights are positioned along the outside edges of the screen. From there, the light is dispersed across the screen, which means the LED/LCD TV can be made very thin. And while the results may be better than CCFL screens, the black levels in edge lighting are not as deep and, if you look closely, the edge area of the screen tends to be brighter than the middle viewing area.

Full-array back-lighting: To take full advantage of LED lighting, some manufacturers use full-array LED back-lighting, where many rows of LEDs are placed behind the entire surface of the screen. Although this makes for a thicker TV panel, the LEDs provide more even, brighter colors and greater contrast. A measurable benefit of full-array lighting can be seen when "local dimming" is utilized, meaning that each LED (or more common, a selected "zone" of LEDs) can be turned on and off independently within the screen, thus providing greater control of the brightness and darkness for each of those areas. Greater contrast levels are achieved by diminishing the effects of light from brightly lit neighboring areas seeping into blackened areas of the screen, which is one of the downsides of LCD screens. In other words, the greater level of dimming control, the better the picture quality.

A number of manufacturers are preferring this technology with impressive results. They include: Samsung, Sony, Toshiba, LG.

Speaking of quality, currently, most LED back-lighting is provided by white LEDs that are plentiful and cost less than their red, green, blue (RGB) cousins. But as popularity and demand increase, and research continues to improve, expect to see RGB LEDs, that provide a much greater color gamut and therefore much richer, denser and varied colors, being incorporated into TVs. Already a couple of manufacturers including Sony and Sharp have models with RGB LEDs.

Features of LED back-lit LCD TVs:

* An LED TV achieves deeper blacks as well as emitting brighter images, thereby producing better contrast ratios;
* They are slimmer (especially edge-LED lighting systems);
* They deliver better viewing angles than other LCD TVs;
* LEDs are long-lasting;
* LEDs are more energy efficient than their CCFL counterparts, and better than plasma Tvs and much better than CRTs;
* LEDs don't use mercury like some other back-lighting methods.

And then there are newer technologies %u2026

OLED displays make use of a thin organic film deposited on its surface with a simple printing process, and present several advantages compared to traditional LCD displays: most notably, they don't require a back-light to function, which allows for much thinner and power-saving displays. LG and Sony have dabbled in OLEDs, but expect to pay a premium for this cutting edge technology for the time being.

But for a lot of consumers, thinner is better, and OLED TVs almost defy logic they're so thin. The problems they encounter is where do you stuff all the things like speakers, tuners, storage drives, etc in around 15mm of space. Current OLEDs also suffer from a limited lifespan compared to other technologies - particularly the blue OLEDs, which have a typical working life of roughly 5000 hours, while, in general, LCD and plasma technologies log in around 60,000 hours, depending on the model.

Then there's Mitsubishi's Laser TV and Sony, Phillips and others will have 3-D TVs on the market from next year. Give it some more time and we'll also have holographic TV added to the mix.