This is a more technical area, and one that more casual consumers might want only to gloss over. Backlighting is just what it sounds like–light that comes from the rear of the television in order to illuminate the image on the Liquid Crystal Display (LCD). It’s a simple enough concept, but there are a number of different ways it can be done.

It’s not crucial for consumers to understand the technologies involved, but different methods have advantages and this is becoming an increasingly important selling point when choosing between certain models and manufacturers, especially towards the higher end of the market. It applies to LCD televisions, not plasma screens.

A common, and older, method of backlighting uses cold cathode fluorescent lamps (CCFLs). This method is cheap, but not very power efficient. A television using this generally won’t have any mention of the backlighting in its sales materials.

A newer and increasingly popular technology is using light-emitting diodes (LEDs). This technology can come in a number of different varieties, but it’s generally a step up from a standard LCD. While not particularly new, the use of LEDs is still a premium technology not found in all HDTVs. LED backlighting tends to offer improved color gamut, contrast ratios, and less power consumption. They are also more reliable and can offer over 100,000 hours of life, compared to CCFLs which are often rated at 20,000 hours.

LED backlighting can be broken down into a few different varieties. These include full arrays of LEDs (with individual LEDs spread out over the entire area behind the screen) and edge-lit, which only places LEDs on the edges of the display. (Here is a Geek.com article on Samsung’s edge-lit TVs.) While edge-lit TV’s generally do not have as high dynamic contrast ratios as full array models, neither can (generally) compare to plasma televisions which have the best blacks and contrast ratios available, thanks largely to a feature known as local dimming.

So while “edge-lit” is a cool term, it isn’t always a good thing, in fact it’s not that different from CCFL lighting when it comes down to picture performance. The advantage that edge-lit TVs do have, is that they are cheaper to produce, they are power efficient, and they can be very thin.

Backlighting is an important component of a high definition television, but it’s a very technical area. It’s something to research on a specific model, but not necessarily base a final decision on.

Here is an infographic, courtesy of Sony, if you want a look into the technology (click to enlarge):