Readers' Submissions

Fact Check: LED TVs

by Bob
(Mesquite, TX)

There seems to be confusion and misinformation about LED TVs. This is a fact-check for those of you who seem to be confused.

1. CCFL (Cold-Cathode Florescent Light) based LCDs won't last 30 to 35 years. This is the same technology used in laptops since the 80's, and under normal use, you will see significant dimming (maybe as much as 50%) within 5 years. If you keep the brightness down and take really good care of it, you might get a couple more years past that. Since they are illuminated by a florescent tube, they have the lifespan of a florescent tube. In some cases, and certainly not a "user-replaceable" process, the CCFL can be replaced, but this would not be cheap or easy to do.

2. Both traditional LCD (CCFL-based) and LED use a Liquid Crystal Display matrix consisting of Red, Green and Blue pixels to construct an image. Some newer LCDs use other colors such as Yellow or Magenta to enhance the color display. In either case, the pixels themselves do not produce light, and must be "back lit" for the viewer to actually see the picture being rendered by the LCD matrix. LED TVs use Light Emitting Diodes for backlighting instead of CCFL backlighting. LEDs are solid-state, require about 1/20th the power of a CCFL, and last for a very long time without dimming. You won't get 30 years out of an LED, but you will definitely get 10. So both of these technologies are really LCD. When we say "LCD", we mean "CCFL-LCD", and when we say "LED", we mean "LED-LCD".

3. The advantages of LED-LCD over CCFL-LCD are:

a. They require much less power to operate. Less power means less heat. Less heat means longer life of the electrical components. A plasma TV gives off as much heat as 2-3 people standing in the room, and CCFLs, although more efficient, still require a lot of power and give off much more heat than LED-LCDs. Both of these will help you save money on electricity -- unless you're using your plasma to help heat the basement in winter, in which case your heating bill will go up.

b. They weigh much less. This means that they can be mounted more easily, provide more flexibility for location, and don't necessarily require professional installation. If you mount a 200+ lb plasma to the wall, you better make sure it's not going to fall. A 60 lb LED-LCD, however, is easily a 1 person job, and the risk is much lower that you will break the equipment or injure someone. CCFLs are lighter than plasmas, but still weigh double or more compared to an equivalent LED-LCD.

c. They last much longer. LEDs are solid-state, and are much less subject to dimming. Traditional incandescent bulbs, including the mercury-vapor projection bulbs used in rear-projection units have parts that literally burn up over time. CCFLs also have parts that erode, wear, or break over time. LEDs are made out of plastic, can't break, and don't wear out. Over time, surge current can erode the light-emitting materials, causing dimming, but you can expect 10+ years out of any LED.

d. Newer LED-LCDs have what is called "local-dimming", which is an array of LEDs that provide dynamic back-lighting, effectively dividing the screen up in to many small back-lit squares. This significantly improves contrast ratio, but can produce "blocking" effects, where you see the back-light rather than the LCD pixels. CCFL-LCDs are side-lit, and do not support dimming.

4. There is a technology called Organic Light Emitting Diode or OLED, made from organic materials, and whose pixels emit light directly without a backlight. This technology is new, expensive, and has a short lifespan due to the organic materials that degrade over a few years of use.

As OLED improves, it promises to provide significantly more vivid pictures and consume even less power than LED-LCD displays. OLEDs are typically printed on flexible material, and the possibility exists for "panorama" displays similar to what you see in movies. The manufacturing process is not very cost-effective today, and the organic materials break down over 1-2 years, making OLED a very poor investment today, but definitely a technology to watch for tomorrow.

Editor's Update December 2012: For a more complete and precise explanation of the pros and cons of LED TVs vs. LCD TVs, please refer to our Plasma vs. LCD vs. LED TVs guide. This takes into account the latest developments in the different TV display technologies to better reflect where each fits best.

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