Connect with us

Why are white LEDs so expensive?

Discussion in 'Electronic Basics' started by Brian, Jan 11, 2005.

Scroll to continue with content
  1. Brian

    Brian Guest

    Does anyone know why white LEDs are so expensive? Looking through the
    Mouser catalog, I noticed that $2 a piece is a cheap as they get, versus
    $0.10 for Red/Green/Yellow. Why is that?
     

  2. An immediate reason is that Red LEDs have been around for at least 35 years,
    with green and yellow following soon after, while white are still
    relatively new. It takes time for things to ramp up so production can
    reduce costs, and for there to be demand which also drives prices lower.

    And while I have no idea how it affects cost, each of the colors of LEDs
    use a different scheme. White LEDs took so many decades to arrive after
    the original LEDs because they had to figure out how to make them (same
    with blue LEDs); it's not a minor change for every color. There may
    be something about white LEDs that cause a higher price, even taking out
    of the equation the early price of any device.

    Michael
     
  3. Not only that, but the blue LEDs have now been around for quite some time,
    along with UV. Yet, they are still considerably more expensive. People
    don't use these if they don't need to. Also, my local electronics supplier
    tells me that, at least in the case of the blue LEDs, they actually do
    cost more to produce. One could ask if this is material costs, equipment,
    higher rejection rate, etc. It would be interesting to compare the
    manufacturing methodolgy for these different LEDs, and also their
    photodiode detector counterparts.


    Dominic
     
  4. Whites, I believe, use fluorescence in order to generate the apparent white.
    Since fluorescence is almost always towards longer wavelengths, they require
    blue led technology to generate the primary source of energetic photons which
    then stimulate the fluorescent responses in the rare-earth materials. Blue leds
    are more expensive to begin with, partly because the processes they use are
    "difficult" and partly because Cree, I believe, has a patent on one of the key
    wafer types often used (silicon carbide?) and anyone using that technology has
    to pay a higher than usual price for access to it.

    I suspect that many of the applications which would otherwise consider the use
    of blue leds for aesthetic purposes (product sales) don't believe that blue
    counts for enough additional value in their products to be worth the very high
    cost, so they use other colors that are much cheaper and live with it. So the
    volume on blue doesn't pick up that quickly, on its own legs. So, probably, the
    price of blue leds is being more driven by the white led usage and that itself
    is more driven by flashlight sales, I'd guess.

    That's just my own meandering and I'm probably wrong on several counts, at
    least. It may also be that there is a perceived value to white and that the
    number of players is small and the market 'controlled' to a sense (at least to
    the degree that Cree controls it), but I've no idea about that. In any case,
    they are more expensive.

    Perhaps Don K. will chip in here and inform us all about it or provide a link to
    a web site that does.

    Jon
     
  5. Danny T

    Danny T Guest

    Fools! If they started with white, they could easily make other colours
    with a filter! :)
     
  6. John Fields

    John Fields Guest

     
  7. Dingo

    Dingo Guest

    www.futurlec.com have them from US$0.70 or there abouts.

    And doesn't white need lots of wavelengths whereas red just needs one?
     
  8. Guest

    Look up http://www.hosfelt.com/, they have some cheaper white leds in
    addition to blues, UV, red, yellow.........etc.....a bit cheaper than
    mouser.

    Also I was under the impression that white leds are actually blue leds
    with a phospher coating in the epoxy ......

    also might want to try http://www.lsdiodes.com/ but they will get you
    on the shipping....at least at mouser or somewhere like hosfelt you can
    add a few more electronics related items to the order.

    also you might want to google "cheapest white leds" and see where that
    leads........
     
  9. Yes, that's true. And anywhere one can get both blue and white LEDs,
    white ones don't cost much more than blue ones do.

    Blue LEDs do indeed cost more to make than red, orange, yellow and
    yellow-green. I believe that a major reason is that the chip "substrate"
    is artificial sapphire (aluminum oxide), except in LEDs by Cree where the
    substrate is silicon carbide. The working layers of blue LEDs are gallium
    nitride and/or indium gallium nitride, and those do not work well on the
    longer-established LED chip substrates of gallium arsenide and gallium
    phosphide.
    Apparently the trouble with putting gallium nitride on gallium phosphide
    is an excessive difference in the spacing between atoms - aluminum oxide
    and silicon carbide provide a better match in that area.
    And artificial sapphire and silicon carbide apparently cost more than
    other substrates because they are so much harder and maybe also because of
    higher melting points.

    - Don Klipstein ()
     
  10. Ray

    Ray Guest

    Supply and demand. I just recently went to ebay and got 50 11000mcd white
    LEDs for about $12 (+$5 s/h from hong kong). There are cheaper places than
    mouser or digikey right now but you might have to wait an extra week to get
    them


    -Ray
     
  11. I just got a keychain LED flashlight at Walgreens that was only $0.99,
    so the white LED it has must be cheaper than $2 since I got a case
    and an on button and a battery while I was at it :).
     
  12. But of course, a key use for white LEDs is for flashlights, and
    one can see quite a variation between cheap and expensive.

    I bought one LED flashlight a couple of years ago, in about the
    same package as those cheap laser pointers. It seemed to put
    out decent light (and the neat thing about those was they used
    three button cells, that were also used in the cheap laser pointers,
    and the latter were even cheaper so a source of batteries).

    But two weeks ago, I bought a white LED bicycle headlight,
    because it was only fifteen dollars. That thing has way more
    light out of it, and it may be brighter than an 2AA Maglite.

    Michael
     
  13. Because the bicycle headlight uses a LED driver the and a high MCD intensity.
     
  14. Martin

    Martin Guest

    I also source my LED's from Ebay, the white ones from UBIDITNOW are a
    very good price. $33 for 100 10000mcd whites, inclusive of shipping so
    that's only 33cents per LED. They are doing 20,000mcd leds for $79
    inclusive of shipping too.
    I do find them to be a little on the flaky side sometimes though.
    I use these LED's for making a small (15 LED) front lamp for use on a
    motorbike. I just use a very simple cct to run these in groups of 3
    with a single current limiting resistor for each group of 3. I find
    that every now and then one LED will blow :(
    I guess you pays your money and takes your choice.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-