LCD, meet LED

Posted on May 17th, 2008 | Permalink

So I was recently asked by someone buying a new computer whether they should consider an LED monitor, or technically an LED-lit LCD monitor. While this technology has not yet seen widespread use in monitors or televisions, I believe it will become much more popular within the next few years.

LCD screens get their colors and brightness from two separate places. The brightness is typically generated by a form of fluorescent bulb (at least in the case of larger LCD screens like those used in computer monitors and televisions), and that light is filtered through liquid crystals to create the desired color, hence the name Liquid Crystal Display.

One problem with using fluorescent bulbs for back lighting is their limited color range, meaning that the “white” light output by the few large bulbs only covers so much of the color spectrum. With LEDs, many small bulbs are used instead of a few big ones, allowing the combination of multiple different colored bulbs to output a much larger color range.

Improved colors are just the beginning. Fluorescent back lights are typically placed around the edges of the screen, with reflectors or diffusers being used to get the light to the center of the screen, which is why you will often see a glow around the edges of an LCD monitor. While LEDs are often set up this way as well to save power and manufacturing costs, the small size of LEDs gives them the potential to be set up in an array across the whole back of the screen, lighting it far more uniformly. Color consistency is also much easier to attain with LEDs, since they can be dimmed without the color of the light changing, whereas fluorescent bulbs are either on or off, relying on manipulation of the liquid crystals to control brightness.

Add to this the longevity of LEDs, which can last at least twice as long as a fluorescent bulb before beginning to dim, and you end up with a pretty strong case for going LED, especially for applications demanding accurate colors within a large gamut. As it stands now, LEDs have yet to establish their hold in the realm of larger screens, but I believe that day is not far off. Next stop, LED bulbs for your living room lamp?

5 Comments

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  1. By Shannon Moeller on May 19, 2008

    While these new LED screens are surpassing the fluorescent bulbs (that I long to call “of yore”), I still think my “one-LED per-pixel plus an amorphous prism to refract the correct color” idea is the way to go. Oh, to be an engineer.

    LED bulbs for your living room lamp?

    Perish the thought. Give me filament and flame!

  2. By Peter Pallock on May 20, 2008

    I too wish we could continue to bask in the gentle orange glow of the incandescent bulb. However, last December Congress passed an energy bill which, among other things, bans Edison’s invention by 2014, starting with the 100 watt bulb in 2012.

    Since fluorescent bulbs are currently the only cost effective alternative, and since unfiltered fluorescent bulbs give me a headache after a few hours, most any other option would be welcome, including LEDs.

  3. By Shannon Moeller on June 8, 2008

    Halogen.

  4. By Aparna on December 11, 2012

    Another factor that they really need to investigate is longevity. It seems as though the higher power LED’s done last long. Perhaps figuring out a way to dissipate the heat generated by the resistors in the LED’s will make for a longer lasting bulb.

  5. By Peter on December 12, 2012

    You make a great point. LEDs certainly have a very long potential lifespan, but at the moment the claims of LED bulb life by most manufacturers fall far short of that potential largely due to the heat issue you raised.

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