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LEDs...

Discussion in 'Lighting and Electrics' started by McCready00, Sep 28, 2008.

  1. McCready00

    McCready00 Active Member

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    Does someone know a good and clear web site where I might find informations about it.

    These are now becoming an important part of the lighting industry. I'd like to read books about it but I am actually giving my time to Nick Mobsky's Practical Dimmers and Practical DMX (interesting books by the way).

    Finally, I just need a link where I could get most of the basic information needed to understand the LEDs.

    I am problably not the only one interested by it.

    Thanks
     
  2. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    LEDs-A Disruptive Technology, by Mike Wood, from Lighting Dimensions, June 2004.
     
  3. McCready00

    McCready00 Active Member

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    interesting.. I'll read it later tonight.

    Thank you!
     
  4. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    Also just do some searching around here. We've had lots of interesting threads discussing LED's in theater. The general consensus is it's really cool technology but it's not quite where it needs to be yet. A little brighter and a lot lower price and we are going to see a massive revolution in theater lighting.
     
  5. phil000

    phil000 Active Member

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    I just wrote a 12 pg paper on them if you want it,
    here ya go:
    http://www.divshare.com/download/5480139-54a

    This is some of my thoughts on the matter, you may or may not agree. I did research on it and know a good little bit about them from a flashlight standpoint. I would love some feedback. (I got an A on this one I think).

    I may be in and out of the forums, so best bet is to email me if I'm unresponsive to this thread.
     
    Last edited: Sep 30, 2008
  6. audereengineering

    audereengineering Member

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    In the opposite direction of the original request:
    Light-Emitting Diodes by Schubert is technical (very)
    It is the best book I have read on LEDs

    phil000:
    Rough grinding on (sand blasting to sand paper) the dome on a LED to experiment with a cheap diffused LED source has been around for at least 20 years.
    You probably want to experiment with a ray tracing program like Zemax but I will warn you that the source approximations are not an extremely accurate model for a LED but should be a good start for this application.
     
  7. phil000

    phil000 Active Member

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    ...I just did it for a class...and it's like a basic intro, hopefully just enough to get the OP a little bit of knowledge...
     
  8. David Ashton

    David Ashton Active Member

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    Given that this was written 4 years ago how have the predictions compared to reality?Can anyone tell me
     
  9. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    Looks to me like it's fairly close on performance. The 2007 projections look about right on performance of a 3 watt LED... the article predicted 2.7 watt LED's producing 75 lumens per watt in 2007. We have gone well beyond that as far as I can tell... although I'm not an expert. Secondly it says that LED's will start competing with incandescents 2007... well some of them are and some of them aren't. If you can afford the good ones, then yes they do compete nicely.

    The only place I see the article is way off is the price doesn't seem to be dropping as fast as it predicted. But that's common with rapidly advancing technologies like this. The price drops rapidly on last year's technology but this years is still way too expensive. You've got your $100 Chinese made pars that have a ton of the old 1 watt LED's but if you want to get into the latest and greatest LED's the price is still pretty high.

    So on the whole, I think it's pretty accurate. I know you are not a believer in LED's David, and I do agree with you that they aren't a viable option for most budgets at this point. But I am convinced that we are just a few years away from a revolution in price and intensity that will bring them into all our theaters.
     
  10. BillESC

    BillESC Well-Known Member Premium Member

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    But I am convinced that we are just a few years away from a revolution in price and intensity that will bring them into all our theaters.

    I couldn't agree more. For example, in the picture below, the fixture on the right was introduced about a year ago selling for $ 200.00, the one on the left has just arrived and is selling for well below $ 100.00

    [​IMG]
     
  11. David Ashton

    David Ashton Active Member

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    So on the whole, I think it's pretty accurate. I know you are not a believer in LED's David, and I do agree with you that they aren't a viable option for most budgets at this point. But I am convinced that we are just a few years away from a revolution in price and intensity that will bring them into all our theaters.[/QUOTE]

    It's not that I don't believe they're any good it's just the over-hype which they receive, even on pro sites people are asking about lighting large cycs with LEDs as a cheap alternative to real cyc lights, when I try to restore some reality to a debate I get accused of being anti-LED.
    It is reminiscent of the fable of "The Emperors New Clothes"
    And if you read the industry literature as opposed to the adverts there are still large hurdles to overcome with spectrum, optics, heat and consistency.
     
  12. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    You are totally right. I've talked a lot about how amazing the Selador X7 Xtra's are. They really rock. But last time I checked it would cost around $60,000 :shock: to properly light a 40' wide cyc with them (It's been a year since I got that quote, so the price may have dropped). The color saturation is spectacular on these instruments and like nothing you can create with gel. The energy savings will be great too. But there are still very few instruments that can compete with the incandescents and those that can are priced 10 times higher. We are starting to see them dominating some rock shows... but they have a lot higher budget than the typical high school or college that you and I deal with.

    Heat is a problem but the better designed instruments (like those Seladors) are designed to handle that with good heat sinks. If I remember right, I think Selador also slightly under drives their LED's to keep them cooler and help them last longer.

    Spectrum is and isn't a problem. It's pretty much impossible with the current level of technology to make a true white light. However, Selador, CK, and some of the other higher end products do an amazing job of additive mixing a very nice white.

    Optics... yeah there are some issues there that someone's going to have to figure out before we get that S4 LED Upgrade kit that I've been dreaming about. However, I'm encouraged that the technology in my MagLED flash light is actually pretty good and I think there's been some good steps forward in this area in the last year or so.

    I know none of them can talk about these things but I would love :drool: to know what ETC, Altman, Strand, Selecon, or even Rosco and Apollo have going on in their R&D labs right now. We can't be THAT far away from leaving LED wash lights in the dust and doing some serious work on ellipsoidal LED's.
     
  13. BillESC

    BillESC Well-Known Member Premium Member

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    Want white? Sun Wash AW

    3 watt LEDs - 42 white - 7 amber
     

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