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Why are blue LEDs so expensive?

  1. Jan 6, 2012 #1
    Why are blue leds so much more expensive than any other colour leds? I could buy a pack of 100 red leds for about $10, and 1 blue led for $4, in Sydney Australia.

    Does it have anything to do with the frequency of blue light being higher than green, red and yellow?
     
  2. jcsd
  3. Jan 6, 2012 #2

    NascentOxygen

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    I can't answer your question, but then that never stops me from responding. :smile:

    A decent blue LED is recent technology, about as new as white LEDs. Reds have been marketed for the longest time. When I was a student, I recall now with wry amusement, how one textbook stated that "LEDs should theoretically produce only blue light, yet blue is the only colour that researchers have been unable to achieve!"

    This must, in part, have led to my developing a healthy distrust of hide-bound theorists.
     
  4. Jan 6, 2012 #3
    blue led's use SiC or ZnS, so im guessing these are expensive compounds?
     
  5. Jan 10, 2012 #4
    Excessive fabrication cost for new materials.
     
  6. Jan 10, 2012 #5

    sophiecentaur

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    You can buy a string of blue 'fairy lights' for just a few quid. A good source if you need several. Very blue and fairly bright. It would depend how bright you need, I suppose.
     
  7. Jan 10, 2012 #6

    AlephZero

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    It's partly a question of "what are people prepared to pay for them" and the manufacturing demand for them compared with other colors.

    Some types of "white LED" actually use blue LEDs to generate the light, plus a fluorescent material to convert it from monochromatic to a "white" frequency spectrum. These are much cheaper than blue LEDs - but they are much more generally useful for lighting purposes and therefore benefit from economies of scale.
     
  8. Jan 10, 2012 #7

    DaveC426913

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    Are the LEDs blue? Or are they white LEDs encased in blue plastic?
     
  9. Jan 11, 2012 #8
    Blue are generally blue. Shorter wavelengths have come about that use phosphors to get a pleasant light.

    The cost is process. While the fabrication is not as elaborate as silicon ICs, it still involves demanding deposition processes. A goodly number of gases and vapors (bubbled substances), and for now, capability that is well behind the demand.

    The semiconductor world is a constantly changing environment. If the LEDs follow the trend, their cost will spiral downwards.
     
  10. Jan 12, 2012 #9
    Yeah, Mike. Just to imagine how much process engineers have to work these days even to get silicon work in 22nm domain is just enough. Silicon technology had a long way of fine tuning its process for productivity (more than 40 years). Even a simple test process for university lab course is very through and complicated. In fab industry many additional factors get included.



    And Blue LEDs (if I'm correct) are only recent discovery. They could not get the sufficient amount of energy gap for target blue wavelength. Thus they used quantum confinement to achieve it. And its a GaN/InGaN/AlGaN process.
     
  11. Jan 13, 2012 #10

    NascentOxygen

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    Strings of christmas lights bear out the tenet of OP's observation. Plenty of reds and bright greens and yellow or orange, but hiding among them, easily overlooked, some puny blues that seem to be working at half brightness. Still a way to go with good blues, I think.
     
  12. Jan 13, 2012 #11
    Most likely you got hold of a blue ingan led. For that kind of money you should be buying a 1-watt high-brightness illumination-class led. This would be around 100 to 1000 times brighter than an indicator led and could in fact cause eye damage.
     
  13. Jan 14, 2012 #12
    Here you go, $0.06 each.

    http://item.mobileweb.ebay.com/viewitem?itemId=120822106983 [Broken]
     
    Last edited by a moderator: May 5, 2017
  14. Jan 15, 2012 #13

    NascentOxygen

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    [strike]Not 6¢ each, they are $6 each.[/strike]

    My mistake. The title does say 100 pcs so you are right, just 6¢ each. :uhh:
    And free postage, to boot!
     
    Last edited: Jan 15, 2012
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