LED Lighting, yet another choice

Discussion in 'Equipment' started by screebo, Nov 23, 2010.

  1. ryanjiang

    ryanjiang Guest

    The problem is that spectrum plot for different LED is not as widely available as MH lamps.

    But look at plot posed by AI, looks like spectrum are wide enough comparable to 20K MH lamps.

    [​IMG]


    [​IMG]
     
  2. GreshamH

    GreshamH Guest

    Most LED manufacturers will supply you with a plot if you ask. I've seen tons of LED plots, every single LED (keep in mind I am talking LEDs, NOT FIXTURES that use multiple LEDs)

    I've seen the AI plots from non AI sources and I must say they didn't look like that ;) Keep in mind that is a combo of LEDs. Odd how when either of the LEDs they use don't show most those spectrums when plotted alone, yet when used together all a sudden those spectrums show up? Seems a bit "markety" to me ;) You can't create a spectrum that is not there. They use two LED's each with a specific bandwidth and they really don't peak in any other spectrum accept for the one they are designed for. That is one of the big issues with LEDs.
     
  3. Gomer

    Gomer Honorary Member

    LEDs hit "more" of the spectrum then MH, but in much broader terms. MH are a lot mroe spikey. Not saying that LED is better, just that their spectrum is not wavelength lacking.
     
  4. Coral reefer

    Coral reefer President

    Can't mixing two colors give a third color?
     
  5. Thales

    Thales Past President

    I like LEDs but only for certain applications. I think the units available are so expensive that the ROI for replacing MH is not worth it. Bang for your buck, MH with a good reflector gets better intensity over a larger area than LEDs. I also don't like how the LED fixtures are changing so rapidly - what you buy today will be replaced by something better next month. I like the idea of LED and plasma but think the market is too volatile right now for me to consider jumping in. I am grateful for all the people who like to spend money and experiment on stuff to keep the manufactures in business until thing settle out.
     
  6. Gomer

    Gomer Honorary Member

    I still think a royal blue bar or two works well as supplemental...just not 100% led..not yet.
     
  7. Thales

    Thales Past President


    I agree, though some people hate them. I have mine set so they reflect into the lumanarcs which takes aways some of the disco feel. Sanjay liked that look as well.
     
  8. Coral reefer

    Coral reefer President

    Yeah sort if thought so. Trick on the eyes
     
  9. sfsuphysics

    sfsuphysics Supporting Member

    In general yes. In reality, no.

    The reality of the situation is you're simply modifying the way items reflect or absorb light, or you're doing something to fool your eyes by transposing colors.

    For instance if you use the Balmer Series of hydrogen, basically hydrogen gas in a tube with a few thousand volts across it, you'll see what looks like purplish/pink color,
    [​IMG]
    this is caused by red, cyan, blue and violet mixed together
    [​IMG]
    However when graphing the spectra similar to the graph that was shown before) you'll see the distinct red, cyan, blue, violet spikes, there's no pink spectral spike, so in that sense you can't magically make wavelengths appear that never where there in the first place regardless of how much color mixing you'll do.
     
  10. ryanjiang

    ryanjiang Guest

    That sucks, it is better to have no such information than having some info which might fool you.

    I was wondering about that before as well, if you look at T5 plot it is more like the LED one. I thought it was just the different way the chart was rendered, maybe just connect all the peaks and smooth it out it becomes the simlilar one as T5/LED plot? I don't know.
     
  11. rygh

    rygh Supporting Member

    I have a really cheap diffraction grating spectroscope, and it is interesting looking at various lights.
    Unfortunately, basically impossible to take pictures through it.

    The LEDs have a surprisingly wide curve. Not at all like the extremely tight spikes you see in fluorescent, like the mercury lines.

    The white LEDs are very broad in spectrum. Which is not surprising, since most of the light is not directly from the diode.
    They have a blue diode, surrounded by phosphors, much like fluorescent tubes, that produces the white.
    The data sheet drawings I have seen for most of the LEDs look quite correct.

    I would say the the T5 plots are less accurate. They seem more spikey in reality than you see on the drawing.
    I do not have a MH light to look at.

    I don't have data on LED fixtures. DIY, so never looked at them.

    You definitely cannot combine 2 spectrums to get a new one.
    Although it would look identical to your eye.

    Recently, there are some new violet/blue LEDs on the market.
    The Rebel LEDs have a great royal blue.
    And now there is an even deeper violet one. Not sure who makes it though.
    It appears that a combination of them might be great.
     

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