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One of the companies I used to work with supplies lighting to agriculture. It's mostly pork and poultry, but I do recall a conversation where the lighting had to be chemically resistant to methane gases when used around cows. T5HO lamps are pretty popular in farming, and lately they're using pretty savvy control systems to alter the animal's Circadian clocks to either counter the effects of less sunlight during winter, or to increase the pace at which animals grow or produce. 20 hour days, for example. I think all of us have seem those little sparks or arcs when changing a fluorescent lamp, sometimes just from rubbing the tips of the lamp on other metal (never mind the electricity itself). If high school kids can light their farts, maybe it's possible that if a barn isn't well ventilated, that a buildup of methane could actually ignite. Wasn't this in a Mythbusters episode?

Or maybe the case is being over stated in both directions to make the whole Obama/ISA thing seem like a bigger deal than it really is?

Just to be clear, that 9 LED board is always attached to a heat sink in the fixture(s) we supply it for. It's one of our OEM clients and we make about a dozen "engines" for them. This one is a recessed downlight with about 1250 source lumens @ 18W power consumption (including PSU losses, etc), so a luminaire efficiency of almost 70 lumens per watt. Channel letter modules should be able to operate without being attached to anything at all - so you're right - the PCB should essentially be the only heat sink. The GWH cabinet is likely warmer than most signs out there and I'm unsure if our EasyStroke being at the top of the TW cabinet is bad, by being where all the heat goes, or good, by being where the heat also exits - but it is what it is. Our testing showed it to increase over the first bit and then decrease a little over 1% per 1000 hours - so a projection of 50% brightness at about 55 hours. Erik's testing in SoCal shows about 12.5% drop after 11.3K hours, but the upswing due to the colder ambient temps will bring this average back in line with our projections. There are peaks and valleys every year, so you have to track over multiple years to plot out a more linear 'average', which can be done a bit better in the GWH that we're not actually a part of. Basically, at 12 hours a day we're projecting 10+ years of usable life, depending on geographical location - but our modules are sort of a lower priority right now. We have some key clients using them and a mix of occasional buyers, but we're really not pushing them like other companies who do nothing but this sort of thing. We have other sign and display stuff that does much better for us and we have little to no competition on some of the products - but again - with key clients only. I guess I should shut up and stop hijacking Manuel's thread. We started with general LED talk, but I've gone a little too much into our stuff... though with the number of times he has jacked other threads, he has a little coming back to him ;) Speaking of which... Dubrovnik? Are you sure? I've been there and even being from a Croatian background, I have to say I'd have a hard time making that choice. It'd be a kick teaching you some of the language, if you want... but you really need to look at Split if the coast is what you have in mind.

Yes, of course. These LEDs are generally not the grade being used in most channel letter modules, and said modules have little to no heat dissipation and use simple fibreglas PCBs and not metalclad PCBs. (I don't know what Manuel is using in his fluorescent type product). In fact, the way Erik has them all clustered in neighboring compartments probably heats the rear of this cabinet even more than a channel letter would, with added surface>air area to help dissipate heat. Channel letters can often create more heat than the LEDs if used in warmer climates, so the test end up being pretty accurate when it's all said and done, but the depreciation is also due to some products being driven at or closer to their limits than other products. We're talking about a wide range of items here with varying levels of ability to withstand fluctuations in heat, incoming voltage and drive current. With respect, the test details clearly state that there was an aluminum heat sink. We use them, so I can tell you with absolute certainty that there is no way that those LEDs attached to anything more than their own PCB would ever reach anything at or even near 105C. You'd have to add heat to the heat sink externally, which in this case means heating the water. Further, it's often drive components that generate as much or more heat than LEDs, believe it or not. Ask Erik to touch the Permlight el Plato's in the GWH and he'll tell you that the resistors are a whole lot hotter than the LEDs. Efficient product design is critical and some are better than others in this respect. For example, we use 2 versions of that LED. One is driven at 285mA (the 350mA rated one in Manuel's report) and the other is driven at 560mA (rated for 700mA). On the 'hottest' light engine, we have 9 such LEDs clustered together on a PCB that is about 3.5" square. We've done measurements with and without heat sinks and drive currents up to 700mA (just to test our boundaries a little) and we never reached anything close to 100C at any point in time. Using a FLIR system to measure at the desired 560 mA and without any heat sink, the max junction temp did not exceed 80C, and with a heat sink (no liquid cooling or anything) it stayed in the upper 60s, which is well within spec. Our on-board switching driver is between 92~96% efficient, so we're not using measly resistors to sink off 40% of the energy of a product that might only be 60% efficient. Heat generation really is limited to the LEDs with very little coming from ICs and such. Again - this is our product and not Manuel's - but it's entirely possible to design products that are efficient and stay within all recommended design guidelines. We're expecting the LM79 data shortly, while the LM80 takes a lot longer.

You're right, they did, and it appears that it may be the new way they're doing things. Looking more closely, though, there are details we need to pay attention to. They didn't use the water to create only the most perfect conditions possible as you are making it sound. They used the water to regulate the case temperature of the product and they did this for 3 different temperatures: 55C / 131F (you really think they were cooling the water?) 80C / 176F (which would certainly not be cooled and probably heated) 105C / 221F (!) (which would certainly require heating of the water) Taking only the best-case results would be a mistake, but weighing the worst case results at 105 degrees - hot enough to burn you on contact and a probably junction temperature of 115 degrees - still suggests the product performs favorably.

I won't get into any of Manuel's products, but can comment on a couple of things as another LED developer. You are correct - there is a difference between chip performance and luminaire performance - the latter is what matters. Knowing the LEDs that Manuel us using I have no doubt that it will be very bright, but will reserve praise or criticism until the LM79 results are shared. LM79 has nothing to do with Caliper and is essentially the defacto measuring stick for any lighting products using LEDs. They do not use water cooled heat sinks for their testing. Most of the time the heat sink is minimal or non-existent, actually, and is generally a PCB with the recommended copper design for thermal transfer away from the mounting pads. Cree, being an American company, has been a big player in trying to steer the DOE in directions that they would like to go. It's not unlike GE trying to write standards for power transmission, Philips for trying to limit PFC to just 70%, or 3M trying to get the DOT specs for reflective sheet to be require a whole lot of their latest materials to be used. That said - products are not excluded based on LED or chip type and if Nichia product is better it will be proven in the testing that Caliper does. It has been proven in some cases, if you know the products they have tested, but they don't release specific product details. You are only left to make educated guesses which results are for which products, which isn't too hard if you follow things very closely. Beyond Caliper, though, the DOE and other domestic "industry groups" certainly do favor Cree as the LED of choice. To win certain bids or grants, you have to use the sponsor's product and Cree has been a sponsor of many of these things from the outset. It's a smart strategy on their part, but I generally have a hard time choosing their product over Nichia or Toyota when the performance, price and ability to work together is better with the latter parties. They listen and respond better with their product offerings IMO. I'll never forget asking one of their product development guys if a particular LED might be possible or become available and being told very clearly "no, why would we do that?". Toyota and Nichia both made this LED (LEDs with 3 or 6 chips in series) and next thing you know - Cree has it too.

I guess the flights were OK last time, or will you be driving out? A car certainly comes in handy if you want to see things in the area - I highly recommend the new bridge out at the Dam.

You mean your PSUs with our lights, pattern sheet, extrusions and design work with the fabricator? ;) It's a shame that certain units along some of the bends have been smacked repeatedly by (presumably) drunk drivers. AD/S out of Corona, CA was the fabricator - having done most of the wayfinding and other feature signage throughout Aria and City Center. They're a great company to work with and we're in the process of doing the new T3 terminal at McCarran as well.

I haven't booked anything yet, but will be in town for sure. Erik - do try the Luxor instead of the Excalibur. Much nicer, and that extra bit closer for walking. Would prefer to do something other than Dick's for the Syndicate meetup as well, but that's entirely up to you. Manuel - as long as things don't conflict with plans of our own, I'm happy to work together. Will touch base later today... are you in Vegas or NZ at the moment?

Yeah - I've had the same November SBI sitting in the mail pile for a couple of weeks now, not knowing that we received a nice plug in Erik's article. So thank-you, Erik, for including us in the LED portion of the article. One thing I wanted to clear up, though, is that pretty much all our products are constant current and not sensitive to the kind of voltage variations that Erik mentioned in the piece. Any power supply between about 10.5 and 14V works just fine. It would have been nice if they had room to post the picture of the completed and installed Solare sign, but they did seem to use your article in it's (more?) original form, compared to last time - so good work. Hopefully it drives some good traffic here as well.

To follow up... Fluorescents and neon also use phosphors to convert blue light to white, so as those products break down, there would be a similar risk of exposure to blue light - perhaps greater with fluorescent considering their shorter life cycle and the number of times they reach break-down stage. Considering how many millions of fluorescent tubes are out there, I would think this would be a far larger safety concern. It's why they recommend those little plastic shades when you get into a tanning booth, for example. In regards to intense light being potentially damaging, that's pretty widely known by everyone - hence my comment about not needing to be a genius to know that (that wasn't directed at anyone personally, it was a rhetorical comment). Any high intensity light source can cause retinal damage, regardless of color or type of emitting source. I've had flash burn from welding so I've experienced it first hand. In regards to LEDs Magazine - for anyone who doesn't know much about it - it's mostly a news aggregator type thing. Anything and everything related to LEDs gets linked or posted and it's up to readers to filter out what they deem worthwhile. It's not some industry approved source of verified info, and is not much different than other trade mags who accept submissions and/or press releases from people in the industry. It's a great site to have bookmarked if you want to hear about what's going on, though very, very little of it is sign or display related.

Thanks Erik - I was at a loss to understand what I said that was a personal attack? Brian - you asked for an LED person to chime in (assuming the article said something damaging to begin with), and I did. The reply to that was "see....", which is hardly a clear point at all. I asked you to be specific about what you thought needed to be responded to - so you went back and edited a question into your previous post. In my next reply I thought I was answering the relevant points (to the question added). It was specifically asked if our LEDs (or any) had blue light in them which I answered, and you chose to construe that as a personal attack? Anyways - forgetting all that - I'm trying to understand what the problem is with having blue light within LEDs? Are you saying that any light source that converts blue light to white supposed to be a health risk?

Perhaps if you'd make a clear point, I could respond with a clear answer. Yes - blue chips are used to create a white light. The issue of 'blue light' has to do with the emitted color, so when you see lighting systems with LEDs (or other light sources) that are between say, 8000-10000K, or actual Blue lights, over-exposure can cause damage similar to looking directly at a lunar eclipse. First off, they don't make any mention of how much exposure is needed, nor do they state that there is any evidence of this being a problem - only something that is a possible concern. Using quality LEDs in the right color spectrums makes this concern moot, but you wouldn't expect the FDA to know necessarily that in the US either, right? Further, it doesn't take a genius to know that looking directly at any intense light is not good for your eyes. This is not something unique to LEDs, but since it was posted on an LED website it was brought up as something to watch out for. If it was a welding website and they mentioned that you had to watch out for flash burn, is somebody supposed to come out and say it's a lie? I don't know what you're looking for here... ?

See what - that you're creating a straw man to argue with? Did anyone claim any lies? How about you tell us what you think the article says. Is it something in the first report from the IES, or the second report from the French Food Agency? Is there something in there that needs to be answered for? Please be specific.

What lies? The IES paper starts by saying that their report is not about LED lighting specifically, but all lighting - and that lighting can effect your health. Umm, if I recall correctly this is something that was stated here and some posters thought it was complete hooey. All lighting, remember. From there, the French Food Agency report gets into LEDs specifically and talk about 'certain lamps' and how blue-ish LEDs can cause photochemical risk when exposed for too long, or for glare (ooh, deadly glare!). They then comment about how exposed LEDs can be too bright for safety - this is already known (ie: their Class 2 laser designation) and recommend optics and diffusers. They're basically saying 'don't look directly into the light'. Problem solved by A) using warmer color tones and B) preventing direct view or glare with optics and diffusers. It's a simple article and the second part - concerns brought up by a food agency no less - are easily remedied by someone who knows lighting.

Yeah. I mean, who needs telephones or electricity, right? Forget traffic signals, let's just go with 4-way stops on all roads everywhere, and make people guess if they're turning the wrong way down a one way street. Driving would be more of an adventure and scare the old people off the roads = safer for everyone!

Speaking of graveyards - is the airplane graveyard in the Mojave north of LA the best one, or are there others? I heard there's a big military one in AZ somewhere...

What does that have to do with human comfort under LED light, though? I can't make any more specific comments until I've had a chance to read the article, but it seems to me that someone is talking about apples and oranges. If it's strictly an efficiency thing then that's one thing, but to say that humans aren't comfortable under LED lights is something entirely separate and entirely dependent on the products being compared, and what questions were asked of people that led to this conclusion. If these details are not stated in the article, then how are any of us supposed to believe the findings? I guess I'll have to pull up some of the studies myself, but there have been many where if the user was not told which light they were under, they often chose LEDs over sodium or halide (for high bay or outdoor) and LEDs over fluorescents for indoor and task lighting. Halogen and incandescent often win out for residential because of their warm tones, but that will generally depend on the products being compared as well. A lot of people really hate CCFL lamps in their homes because of the color, among other things.

I don't disagree with this at all - Marcus is extremely knowledgeable about neon. He is not some trade magazine journalist that writes fluff at all, but he certainly does have a rather large body of work spanning many years that has gone out of its way to support neon. I'm certain that he was very thorough with the product chosen and I'm certain the results came out the way he expected them to, otherwise he would not have submitted the article. I highly doubt anyone at the magazines would mistrust his detailed submission, or fact check his findings if they haven't bothered to do them with other material that has been discussed on here. If no names are mentioned, how is anyone able to confirm or deny the findings? Convenient, no? Does anyone have a link?

I haven't received my email link to the online edition yet, so I haven't seen the article, but I do expect to find it an entirely predictable write-up. It would be quite ironic if the article was taken at face value by everyone, though, considering the history that exists in attacking the source of other specious reports by people with a leaning towards one technology or another. I wouldn't trust Marcus Thielen to present the info in an unbiased way any more than say, GE about their energy savings, so I'm interested to see what LED products were hand picked to make his point.

As for the video - someone needs to make an avatar out of that bit at 0:48. Classic Kirstie.

That patent is proof that the USPTO is off its rocker. It never should have been granted in the first place since many, many products of a similar type existed before the 2003 filing date. If JT was going to blow the wad suing someone, why pick GSG of all companies? Pick someone bigger that you can actually win some decent financial reward from. I predict that not only will JT lose and have to pay GSG for all their legal fees, but that their entire patent will be invalidated. .

That's a different way to say the same thing I did, Erik - I didn't imply that they wanted an atheist state. I was pretty clear that you can believe anything you like, but that they wanted to keep the influence of religion away from political decisions - because allowing the church/faith to influence policy is exactly the problem they saw overseas and did not want to repeat. That's not really the case nowadays, though. In the US, you can't get elected if you're not viewed as a strong Christian. In Canada, it's the complete opposite - we demand that religion be kept out of politics, which seems to be "more American" than what is currently happening down there. You start bringing up your faith and there's no way you'll get elected up here.

Ha. It's too bad I would never get elected due to my (lack of) religious beliefs. You've got people pegged pretty well, though ;)