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Thread: New LED bulbs as a blacklight alternative?

  1. #1
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    Default New LED bulbs as a blacklight alternative?

    Just wanted to give you guys a heads up that the new Philips LED bulbs are actually made with bluish LEDs inside, and a removable phosphor
    http://www.edn.com/electronics-blogs...r-down-Part-II

    I haven't had a chance to look at the spectrum yet (hopefully should be able to in early january), but based on the descriptions these may be a cheap source of UV or deep blue LEDs (18 LEds per bulb, bulbs costs $20 or so).

  2. #2
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    More than likely they are going to be around 460nm.
    chad


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  3. #3
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    Philips LEDs have a dominant blue wavelength of around 447-448nm. Cree's a bit higher at around 450-452nm. Visually mose people would be able to tell the difference.

    Black lights by technical terms are UV-A and around ~360-390nm, although industry specs vary.

    LED's are inherently a poor economical source of UV-A, although they are efficient at producing it.

  4. #4
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    From what I have seen, discharge lamps still trump LEDs for blacklights. I have a couple of $10 helical fluorescent bulbs that, each one, out performs a $100 LED blacklight fixture... LEDs have a long way to go.
    Last edited by absolom7691; 02-21-2013 at 21:23.
    If you're the smartest person in the room, then you're in the wrong room.

  5. #5
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    Absolom,

    I completely disagree with you. I have several ADJ UV LED Bar 16's, and while they do produce a fair amount of visible light, they FAR out perform even the largest discharge lamps I have compared them to (and are smaller, lighter, cheaper, etc.). That being said, I have started seeing shorter wavelength 365nm 1-watt diodes on ebay, so it's only a matter of time before they end up in a UV fixture.

    -Eric

  6. #6
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    I speak from the standpoint that I want my blacklights to emit very little visible light. In that realm, I have not seen LEDs come close to discharge lamps. If you were to fliter out the visible light generated by LEDs, you would be left with very little UV. I agree that LEDs are getting better and as they do, they will be a more viable source of UV but currently, I find LEDs to produce way too much visible light for the amount of UV generated. For DJs and clubs, LED blacklights are perfectly fine and actually, the visible light that they throw out enhances the effect on a dance floor. For theatrics and set illumintion, discharge lamps win.
    If you're the smartest person in the room, then you're in the wrong room.

  7. #7
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    Eric, would you rate them as more effective than the E40 UVs? Have contemplated building some UV LED bars but the high end UV emitters are still quite expensive. Cheers.

    OP, as previously answered, those are around 450nm royal blue LEDs via remote phosphor conversion. Cheap source of LEDs perhaps, they won't be the most efficient available though. Lasers are catching up too, interesting times ahead. Funnily enough the two year old XML leds were approaching 60%+ efficient blue led sources, once stokes losses and other impediments were factored in at low currents. Try buying blue leds that good on open market even today..

  8. #8
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    To follow up a little more with what I was saying is in a club setting, LED blacklights work well because they will bathe the clubbers and the floor in a deep violet light which looks great. If there were little visible light emitted, the lights would look terrible, especially if the clubbers were wearing clothing that didn't fluoresce under UV. In theatrical lighting, you want your set pieces with UV paint and possibly actors with fluorescing costumes to illuminate. What you don't want to is to wash your set in violet light. I guess I wasn't clear in my intended application of the blacklights when I spoke originally.
    If you're the smartest person in the room, then you're in the wrong room.

  9. #9
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    Absolom-

    While I agree that the LEDs do in fact put out more visible light than conventional lights using Wood's glass, I also think that they do a better job of fluorescing. I assume that this is because the UV LEDs produce a slightly longer wavelength. The visible light produced is a compromise, but in the DJ/club world it is a reasonable trade off.

  10. #10
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    I think I have posted this before...

    LEDs are made down to 365nm which is the standard blacklight wavelength. The price on them goes up and they are somewhat of a specialty. I have a phoseon LED light unit that works at a center of 395nm. Very bright but does throw more visible light than the 365.

    http://www.phoseon.com/products/StarFire.html

    That guy is about $4k.

    I did some macrophotography with fluorescent dye powders with it:

    http://www.flickr.com/photos/6729211...7629551557170/

    -Jerry

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