In 2009, Samsung provided a huge success story with their LED TV series. Samsung had set a corporate target of 2 million unit sales for that year. When all the smoke cleared, they had exceeded their own expectations by over 25% - with sales of over 2.6 million units. Their success can be attributed to a widespread advertising campaign coupled with an excellent product. Not only that, but Samsung is committed to improving the technology and expanding the range of their offerings in order to take their place as the market leader in LED TV sales.

But let's take a closer look at this - since it appears that this new form of television may not be exactly what it purports to be. The reason for this is that the term "LED TV" is not completely accurate when describing this new TV platform. Without getting into technicalities, the term LED TV may lead one to believe that the display is a true LED display. This wasn't the case with Samsung's line of televisions.

What is a "true" LED Display?

A true LED TV is one in which LEDs are the primary components that will produce the display's images instead of using an LCD panel to display those images. Actually this was not possible with Samsung's TVs, since the technology didn't exist to accomplish this. The sheer size of LEDs limited their use for images to very large screens that would only be seen in public events and advertising. Current LED TVs are best described as LCD TVs with LED backlighting.

If you read the TV's advertising brochure carefully, you'll note that the use of LEDs (light emitting diodes) is confined to producing the light source for LCD panels. Knowing this fact might make the consumer a feel a bit deceived - but there are plenty of reasons to switch to an "LED" TV, even if it's really an LED backlit LCD TV. Let's take a look at this from an advertising point of view.

The difference between an LED and an LCD is quite basic

First and foremost, you need to know that an LCD panel doesn't produce light. LCD stands for "liquid crystal diode" which is a matrix of liquid crystals that require light being passed through them from a separate source, to make the crystals visible. Applying an electric current to the LCD panel will allow light to be altered and deflected to produce the colors and images that are seen by the viewer.

So how is the light produced in an LCD TV?

Up until recently, the production of the light needed to generate an image on an LCD TV was accomplished by CCFLs (cold cathode fluorescent lamps). This is the light source that is currently being replaced by LEDs. The question one might ask at this point: "If TVs are still using LCD technology and the actual display is not composed of LEDs, then what's the point of an LED backlight?" In order to answer that question, we'll need to take a look at some CCFL disadvantages and if these issues can be improved upon through LED backlighting.

CCFL technology has its own problems

So just what are the problems associated with CCFLs? Well, there are actually two main concerns. First, there is an inability of LCDs to produce true black images and they have a limited range of colors. Using a CCFL makes it relatively impossible to produce a perfect black image. The reason for this rests with the fact that the lamps must always be switched on. In this case, the LCDs are not capable of completely blocking the CCFL light, thus some of it will leak through - so no perfect black.

This also makes the images on the display a little blurred or less than really sharp. Not only that, but the quality of light that can be produced by fluorescents limits the range of colors that can be displayed. To be fair, this limitation has been improved upon with the use of more effective lamps.

LED has improved on CCFL

In order to understand how LEDs have improved on both of these problems, we need to take a look at their characteristics and how they pertain to their use in TV technology. First of all, LEDs are smaller components when compared to tubes or fluorescent lamps. This will allow them to be placed in the rear of LCD panels. The most important thing, though, is that the LEDs can be switched off individually. Therefore, light leakage is no longer the issue. Instead of attempting to block light, the light is completely turned off, which is known as "local dimming".

The best picture possible

It should be noted, though that this solution is not yet so simple, since it involves great expense in order to produce LCD TVs with enough individual LEDs to make it practical to turn them off individually, therefore the LEDs must be controlled in blocks. With this advantage, areas of improved black coloration can be attained. However, where there are light and dark areas displayed simultaneously, a compromise must be reached with the LEDs where some are switched off and some are switched on - and some light might leak into the dark areas. The best image is therefore attained when most of the images on the display are black.

Colors are important too

An improvement in the range of colors is another quality brought about by the use of LED technology. This is termed "color gamut". LED's, through their inherent properties, can produce a light that is more "white" than the light produced by fluorescent lamps (a broader spectrum of light is produced). Therefore, the bottom line is that LED-LCD TVs can produce a wider range of colors which will enhance the images on the display in order to make them appear more intense to the viewer.

Edge-lit vs. rear-lit TVs

Besides the advantages to be considered with back-lit LED TVs, we should also consider TVs that are edge-lit, as well. Edge-lit TVs have their own advantages, but some of the advantages that come with using LEDs will be reduced. With edge-lit TVs, the major advantage is that LEDs are not as large as fluorescent lamps - so the TV's thickness can be greatly reduced. This has led to the production of TVs that are only 1 - 2.5cm in thickness. The disadvantage is that the truer blacks achieved by back-lit local dimming cannot be achieved. Even so, the less complex design of edge-lit TVs has resulted in them being less expensive than back-lit models. Their thin designs will also allow edge-lit TVs to be mounted on a wall - like a picture.

The type of LED uses to illuminate an edge-lit TV is also different than those that are used for back-lit models. Back-lit LED TVs use red, blue and green (RGB) LEDs which can produce a whiter light and thus improve color range. Edge-lit TVs use white LEDs whose color range is similar to that of conventional LCD TVs which use fluorescent lamps.

Quality is the bottom line

No matter what TV you're considering, you certainly want the best quality for your hard-earned dollar. We've already covered that rear-lit LED TVs provide a better quality picture than edge-lit TVs, due to an improved color range and contrast ratios obtained from RGB LEDs. Edge-lit TVs are thinner and more economical. LEDs are also more eco-friendly since they use about 40% less power.

For purposes of quality, it should be noted that LEDs are considered more reliable than fluorescent lamps and the performance doesn't degrade. Fluorescent lamps will become increasingly dim until they eventually fail altogether. At that point, it usually isn't cost effective to replace the lamp - rendering the TV useless.

What does the future hold?

In 2009, the success of LED TVs has indicated that the future of television is moving in the direction of improved LED technology. It will only be a matter of time until LED TVs represent the standard in television viewing - completely replacing current conventional CCFL-lit LCD.