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Maggic
GPBobby
60 vdc is still too high for the small number of diodes found in most lamps. ...
Future of SSL LED lighting is not dim, but it’s flickering
David Benjamin
3/27/2012 8:33 PM EDT
SAN JOSE -- Could Michele Bachmann be right about advanced lighting technology?
Congresswoman Bachmann, former Republican presidential hopeful, has led a campaign for several years in defense of the historic Tom Edison-style incandescent lightbulb, against government pressure for consumers to adopt new, more energy-efficient lighting solutions.
Michael Poplawski, meanwhile, has led one of the government’s teams – at the Pacific Northwest National Laboratory – seeking to solve issues that currently hobble the widespread deployment of LED (Light Emitting Diode) technology, which remains both more expensive and far more efficient than Rep. Bachmann’s beloved tungsten-filament vacuum tube.
“Complicated,” was the commonest word from Poplawski, senior energy engineer at the Portland, Oregon national lab, as he spoke to a session at the DESIGN West conference here Tuesday. He cited numerous complications in the effective use by consumers of LED lighting, and obstacles to reducing costs for the technology.
One of the points Poplawski stressed was that every LED light is a solid-state (SSL) electronic device, while a lightbulb is just, well, a lightbulb. In a presentation that exceeded its planned duration by some 30 minutes, Poplawski dwelt on four problems that his group is working to resolve: flicker, dimmability, power quality, and lifetime limitations linked to “driver reliability.”
Flicker, for example, is not just a relative of the yellow-bellied sapsucker.
Flicker is inherent in every form of electric lighting and it affects everyone differently, according to individual levels of visual sensitivity. “A good chunk of people,” said Poplawski, with a measure of awe, “are seeing things (flicker) at upwards of a thousand hertz.” Flicker’s biggest moment in the limelight occurred in the film, “The Andromeda Strain,” when the stroboscopic flashing of a laboratory light caused one of the characters to suffer an epileptic seizure.
Poplawski mentioned the danger of seizures, and added other side-effects of flicker, including headaches, fatigue, blurred vision, eye strain, reduced visual task performance and distraction on the job.
The good news about LED lighting is that it can reduce flicker, especially compared to standard fluorescent lights. The bad news is a determination by researchers that flicker – which is consistent and predictable in current lighting systems – is more “complicated” in SSL. It tends to vary substantially, both in amplitude and frequency, in various LED bulbs.
Among the solutions Poplawski’s national lab is exploring is the development of LED solutions with minimal flicker, which requires researchers to identify and measure qualitatively (in terms of human reaction) the presence of flicker. In the end, flicker must be measurable in a way that its level can be reported to consumers in a way they’ll understand it.
Among other issues with which Poplawski’s team is wrestling is dimmability. Many homes are equipped with dimmers, virtually all of them designed to dim conventional incandescent and fluorescent lights. The difficulties of designing LED bulbs that react to existing dimming technologies required Poplawski 20 minutes to explain. The adaptation is not easy. Poplawski boiled it down to the fact that consumers don’t know what will happen when they use their twentieth-century dimmer to soften the glare from a post-millenial high-tech bulb.
“There’s no predictability today,” said Poplawski. “We operate in a built world with existing products and there, the challenges are significant.”
Similarly difficult is the issue of power quality, the consistency of power flow into the home and its lighting system. “Events” like lightning strikes and power surges can affect LED lights in different ways than they impact older systems. Moreover, the addition of SSL networks to existing power, cable TV and telephone networks – often clustered together on the same utility poles – can result in interference that compromises one or all of the networks.
Poplawski also cited the problem of “driver reliability.” Old-fashioned “drivers” – or lamps -- are often inappropriate vehicles for new-fashioned LED bulbs, causing problems like overheating that can shorten the operating life of the new bulbs. If the bulbs blow out earlier than promised, the advantage of the new technology shrinks significantly.
Indeed, thousands of new bulbs screwed into old sockets and ancient sconces have died well before their predicted demise, souring many consumers, especially the Congresswoman from Minnesota, on the promise of LED lighting. “You don’t know,” lamented Poplawski, “where people are going to stick things.”
In the end, Poplawski found himself suggesting an infrastructure problem similar to that hindering the use of electric automobiles. The installed power-supply base is incompatible with the new forms of power.
President George W. Bush launched the lightbulb wars in America by signing the Energy Independence and Security Act of 2007, which recommended a phase-out of the tungsten-filament bulb. Five years later, however, Rep. Bachmann’s cherished GE Soft-White is still ubiquitous in the land. Apparently, it will remain so for many years to come, glowing wastefully beneath dusty shades in graceful but obsolete drivers (lamps).
Congresswoman Bachmann, former Republican presidential hopeful, has led a campaign for several years in defense of the historic Tom Edison-style incandescent lightbulb, against government pressure for consumers to adopt new, more energy-efficient lighting solutions.
Michael Poplawski, meanwhile, has led one of the government’s teams – at the Pacific Northwest National Laboratory – seeking to solve issues that currently hobble the widespread deployment of LED (Light Emitting Diode) technology, which remains both more expensive and far more efficient than Rep. Bachmann’s beloved tungsten-filament vacuum tube.
“Complicated,” was the commonest word from Poplawski, senior energy engineer at the Portland, Oregon national lab, as he spoke to a session at the DESIGN West conference here Tuesday. He cited numerous complications in the effective use by consumers of LED lighting, and obstacles to reducing costs for the technology.
One of the points Poplawski stressed was that every LED light is a solid-state (SSL) electronic device, while a lightbulb is just, well, a lightbulb. In a presentation that exceeded its planned duration by some 30 minutes, Poplawski dwelt on four problems that his group is working to resolve: flicker, dimmability, power quality, and lifetime limitations linked to “driver reliability.”
Flicker, for example, is not just a relative of the yellow-bellied sapsucker.
Flicker is inherent in every form of electric lighting and it affects everyone differently, according to individual levels of visual sensitivity. “A good chunk of people,” said Poplawski, with a measure of awe, “are seeing things (flicker) at upwards of a thousand hertz.” Flicker’s biggest moment in the limelight occurred in the film, “The Andromeda Strain,” when the stroboscopic flashing of a laboratory light caused one of the characters to suffer an epileptic seizure.
Poplawski mentioned the danger of seizures, and added other side-effects of flicker, including headaches, fatigue, blurred vision, eye strain, reduced visual task performance and distraction on the job.
The good news about LED lighting is that it can reduce flicker, especially compared to standard fluorescent lights. The bad news is a determination by researchers that flicker – which is consistent and predictable in current lighting systems – is more “complicated” in SSL. It tends to vary substantially, both in amplitude and frequency, in various LED bulbs.
Among the solutions Poplawski’s national lab is exploring is the development of LED solutions with minimal flicker, which requires researchers to identify and measure qualitatively (in terms of human reaction) the presence of flicker. In the end, flicker must be measurable in a way that its level can be reported to consumers in a way they’ll understand it.
Among other issues with which Poplawski’s team is wrestling is dimmability. Many homes are equipped with dimmers, virtually all of them designed to dim conventional incandescent and fluorescent lights. The difficulties of designing LED bulbs that react to existing dimming technologies required Poplawski 20 minutes to explain. The adaptation is not easy. Poplawski boiled it down to the fact that consumers don’t know what will happen when they use their twentieth-century dimmer to soften the glare from a post-millenial high-tech bulb.
“There’s no predictability today,” said Poplawski. “We operate in a built world with existing products and there, the challenges are significant.”
Similarly difficult is the issue of power quality, the consistency of power flow into the home and its lighting system. “Events” like lightning strikes and power surges can affect LED lights in different ways than they impact older systems. Moreover, the addition of SSL networks to existing power, cable TV and telephone networks – often clustered together on the same utility poles – can result in interference that compromises one or all of the networks.
Poplawski also cited the problem of “driver reliability.” Old-fashioned “drivers” – or lamps -- are often inappropriate vehicles for new-fashioned LED bulbs, causing problems like overheating that can shorten the operating life of the new bulbs. If the bulbs blow out earlier than promised, the advantage of the new technology shrinks significantly.
Indeed, thousands of new bulbs screwed into old sockets and ancient sconces have died well before their predicted demise, souring many consumers, especially the Congresswoman from Minnesota, on the promise of LED lighting. “You don’t know,” lamented Poplawski, “where people are going to stick things.”
In the end, Poplawski found himself suggesting an infrastructure problem similar to that hindering the use of electric automobiles. The installed power-supply base is incompatible with the new forms of power.
President George W. Bush launched the lightbulb wars in America by signing the Energy Independence and Security Act of 2007, which recommended a phase-out of the tungsten-filament bulb. Five years later, however, Rep. Bachmann’s cherished GE Soft-White is still ubiquitous in the land. Apparently, it will remain so for many years to come, glowing wastefully beneath dusty shades in graceful but obsolete drivers (lamps).
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daleste
3/27/2012 11:39 PM EDT
Things like this should only be driven by the market. If you make a better mouse trap, the world will beat a path to your door. As soon as it is more economical for me to buy SSL, I will switch. Until then, you know who will be getting my hard earned dollars. For the government to step in and mandate the change is just more of our liberties evaporating.
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Nick.Radonic
3/30/2012 10:44 PM EDT
Your liberty to consume petroleum sourced fuel to generate electricity to waste in an inefficient means, becomes my social cost in supporting a global military tasked with securing oil flows around the world. The push for more electrical efficiency in appliances and in lighting and industrially is to reduce how much we depend on petroleum.
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LEDAgree
3/28/2012 12:49 AM EDT
The market change to SSL lighting is, contrary to public and misinformed opinion, not government mandated on a national level, but subscribed to a global convention. The incandescent light bulb is not banned, but at the end of it's production in countries around the world. When countries such as China can make the change to SSL or the less expensive CFL technology due to the huge advantages for energy and the dependence on non-renewable energy, they now set the example while we, the US believe everything is big government and an infringement of our rights. We live in a global world. Turn on your computer and look around sometime.
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elctrnx_lyf
3/28/2012 1:37 AM EDT
I think SSL will be the future considering the fact that it offers many advantages like power saving and longer term reliability. But at the same the infrastructure around the power generation and distribution also shall be improved.
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subman
3/28/2012 2:22 AM EDT
LEDAgree, my computer is on, as is the case for anyone who is reading this (not a very perceptive suggestion, by the way!). What global world should we join? One of Europe, where econonies are stifled under the growing beaucratic state? One of China, where freedom is a concept that may develop in the future? I choose neither, and I hope many more do the same in November.
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subman
3/28/2012 2:33 AM EDT
In the US, incandescent bulbs are being phased out by law by wattage (I'd call that "banned") in the US. 100W was phased out in CA last year, and is phasing out in the rest of the US this year per congressional mandate. Next year comes 75W, and so on (all part of the same bill, already passed). Not sure what sort of linguistic contortion LEDAgree is attempting...technically the bulb itself is not banned, just the sale of it. Stores can still sell their stock, so it will take several months to see the effect. If you want to make your own bulbs, go ahead, I think that is legal. You just can't sell them or buy them. Ok, you're right, not banned. The wording in the legislation is a little obscure for most people - it sets lumens/watt minimums rather than "banning" incandescent, but the effect is the same. You won't be able to buy 100W, 75W, etc. incandenscent bulbs. And yes, the lower wattages are not banned for now. How many 40W bulbs do you have in your household lighting? You've got a few years left before those no longer meet the lumens/watt requirements in the passed legislation. Enjoy the dim light, at least it doesn't flicker.
I personally like that I can screw in a bulb, not have any flicker, and dim it with a simple, inexpensive, old-fashioned, voltage-varying slider switch. I am baffled at why Michelle Bachman is pillorized for supporting the freedom to buy a darn light bulb. Seems even more bizarre to me that congress acted to ban light bulbs.
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subman
3/28/2012 2:33 AM EDT
The banning of the 100W and 75W light bulb has been done without fanfare, because those who support it are hoping the majority of the country simply doesn't notice. I suggest you write your congressman, and respond vociferously to silly, distorted posts that characterize banning light bulbs as a failure to follow the great example of China. When did it become seditious to sell 100W light bulbs in the US? Last year in CA, Oct 2012 in the US (after a short reprieve pushed through by Bachman's evil cohorts) in the rest of the country. Google it.
Don't buy into the semantic distortions, or the attempts to characterize supporters of economic freedom as Luddites. The real Luddites are those who don't believe in letting AS's invisible hand do its work. Turn off your computer for a bit and read an economics book.LEDAgree, my computer is on, as is the case for anyone who is reading this (not a very perceptive suggestion, by the way!). What global world should we join? One of Europe, where econonies are stifled under the growing beaucratic state? One of China, where freedom is a concept that may develop in the future? I choose neither, and I hope many more do the same in November.
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Moonshine
3/30/2012 10:00 AM EDT
Americans have trouble turning off lights. The result has been reducing the waste by making them more efficient.
Michelle doesn't care one way or the other, she just knows a good sound bite when she spots it; but I enjoy her so I send her $25 for campaigning when I can afford it.
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Nick.Radonic
3/30/2012 10:54 PM EDT
Adam Smith's (AS's) invisible hand of the market does not exist. Once marketers and advertisers pour money into changing our preferences there is no fair dispassionate market left. As for Europe, at least people there don't go broke for medical care, and in some of the countries universities are free or almost free. AS for the larger wattage incandescents, I thought people were working on increasing their efficiencies through heat reflective coatings. If some technology works, then incandescents will be in the market again.
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GPBobby
4/8/2012 1:06 AM EDT
What part of a free market economy don't you understand? Without advertising exactly how do you expect customers to make informed, self-serving purchasing decisions? I would certainly agree that advertising needs to be honest. Oh--your 'free' universities--do the profs work for nothing over there? If not, who pays them?
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agk
3/28/2012 7:11 AM EDT
The author has discussed about the effects of flicker coming out of the light bulbs. It is very true. I compared the 4 ft tube light with inductive ballast and with electronic ballast. I found there is a great comfort my eyes felt with electronic ballast generally this works around 40 kHz. Because the light has high frequency flicker which is not detected by the eyes. The inductive ballast works at line frequency 50 or 60 hZ give us visible flicker. A LED light generally works on PWM principle at a higher frequency than the line frequency and so the flicker problem is minimum or not visible at all.
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GPBobby
4/8/2012 1:10 AM EDT
In addition, in the case of "white" LEDs, the phosphors also have a short persistence which helps to level any current caused flicker.
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sierra tango
3/28/2012 1:47 PM EDT
change is inevitable....growth optional..
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mike.seiler
3/28/2012 2:32 PM EDT
@agk I agree completely. I had never heard or thought of led flicker being an issue at the frequency they operate at. Why are they wasting time on this.
Also why be overly concerned about making leds fit traditional fittings. Light fittings, not just the bulbs that fit them have limited lifetimes as well.
Many people update them when they paint a room
and a lot of fittings actually fail from the heat of incandescents.
If you can buy a whole fitting with led lamp for the price of an led bulb that fits bc or edison screw fittings. I know I'd rather have a whole fitting.
With the proliferation of fluroscent fitting formats in the past 20 years and add to that the halogen formats etc I wonder whether it is more of importance to build an led bulb for performance and reliability than be concerned about backward compatability.
You only need to look at handheld torches to see nobody was concerned about throwing out their old incandescent torches for the bright new led torches available.
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Robotics Developer
3/28/2012 2:44 PM EDT
I am much less concerned with the flickering as I am with the short life and high costs for the LEDs. The day to day annoying issue that I have run into with a number of the LED lights is the high frequency whine that the power conversion circuit generates. This is really a background but hard to ignore noise. The dimming issue is a bother but never bulbs can be dimmed (not sure how they are doing it, I don't own any). I went out and bought a 4 pack of 100W good old fashioned light bulbs just to have them. I resent the nanny state regulating things that directly impact me and wish the government would allow the free market to drive innovation and improvements not silly laws.
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katgod
4/4/2012 3:28 PM EDT
There is no such thing as a totally free market, all markets are regulated to some degree. I do agree there is such a thing as over regulating a market and the incandescent might be one of those as I think it will probably die a natural death if left alone. Please also consider that almost all the people who supply your electricity are regulated.
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Kuli2012
3/28/2012 4:21 PM EDT
Silly question, but don't you realize the light bulb ban was overturned in December 2011? It was snuck in as part of the budget extension. Now, companies have still begun phasing out the 100w bulbs, because it's the right thing to do from an efficiency standpoint and they probably figure it's only a matter of time for it to come back. I personally prefer incandescent over CFL (which have a grossly overrated lifespan estimate) but I did just switch all my landscape lights to LED. Same brightness & color rendering with 1/10 the power used. And no flicker.
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Frank Eory
3/29/2012 7:46 PM EDT
The article discusses the challenges of LED lighting as a replacement for Edison socket incandescent bulbs -- an application of LEDs that to me seems absurd.
A great deal of efficiency can be gained by simply replacing incandescent bulbs with CFL bulbs, for those who need to adapt into existing old lamp sockets. For those who want LED lighting, here's an idea -- buy new lighting fixtures that are designed for LEDs.
Your mention of the landscape lights is a great example of a good fit between the technology and the application. Flashlights and automotive headlights might be other examples.
In the area of lighting, trying to shove a square peg into a round hole is neither necessary nor wise.
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JimJarvis
3/28/2012 8:57 PM EDT
CFL's and electronic ballasted T8 tubes are demonstrably more efficient than incandescents.
I cut my church's electric consumption by 50% by re-lamping.
LED's? Not so fast. Not so efficient. Part of the apparent brightness is more condensed beam.
Glare results. Drive circuits are relatively complex..and you have to account for full life cycle costing--the energy it takes to MAKE the LED array and drive circuits, in the analysis. So they're nowhere near as efficient as commonly claimed.
LED's make sense in traffic signals and commercial vehicles, where the labor costs of maintenance are significant. Elsewhere, not so much.
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Athlor
3/28/2012 9:42 PM EDT
Fare thee well incandescents but I shall not miss you.
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kinnar
3/29/2012 6:48 AM EDT
The challenges is very well explained by Poplawski and they are somewhat complicated to be handled in present day technology and scenario. But the good news is LEDs have taken it place in many lighting applications at entry level and it is pushing very hard from both the ends so the technology will finds it way to penetrate in other lighting applications as well.
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Wobbly
3/29/2012 4:46 PM EDT
You can still buy 100W and 75W incandscent bulbs. IR coated Halogen bulbs meet the current guidelines. Even better, you can get the lumen equivalent of a 100W 'standard' bulb using only about 80W, and they have the same 'instant on', the same dimmability, the same cold weather performance.
Until the LED technology matures, and I don't believe it will be based on 'Edison' based bulbs, I'll be using mostly CFLs, with a few IR Halogen bulbs in particular locations.
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KGW4449
3/29/2012 9:19 PM EDT
I just purchased the newest Plilips 60 Watt equivalent LED for $24.95 from Amazon. I bought since it got rave reviews.
I'm extremely happy with bulb so far. It provides a diffuse light pattern very similar to a 60 Watt incandanscent bulb. It's color spectrum seems identical to an incondescent. It dims nicely with no flicker, at least to my eyes. The one disconcerting thing i s that it doesn't get redder as it gets dimmer. I haven't had it long enough to comment on longevity but, at 12 Watts, you can touch the heat sink and not get burned.
It still costs too much for general use but the price should drop significantly with economies of scale.
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smooooth
3/30/2012 3:54 AM EDT
I own a business which has been developing different LED lighting applications for several years.
I've never had any issues with 'flicker'!
I have worked on 'retrofit' lighting designs before but the marketplace needs to realise that a fundamental re-design of the light fitting itself is required - how we distribute the light created by the LED/LEDs in a space is the key. Simply replacing a conventional lightbulb with an LED lightbulb does not seem like the ideal solution.
For me, LED driver technology is already mature -people just don't understand how to apply/use it! Plus....expensive!
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John.McVey
3/30/2012 4:23 PM EDT
Has anyone else noticed the poor reliability of the driver/ballast in today's CFLs? They don't last anywhere near the life of the tube. CFLs contain a small amount of mercury and my bet is most people don't properly recyle them. Due to the shorter than expected life, the landfills will have much more mercury than the initial estimates would have predicted.
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SherpaDoug
3/30/2012 4:56 PM EDT
10% of the lights in my house are in closets. They are used for a few seconds at a time, between 0 and a few times a day. Most of these incandescent bulbs are original to when the house was built 25 years ago.
What is the payback period for doubling the efficiency of a bulb that is hardly ever used?
Low initial cost, rapid starting, and good color quality are the only things that are important here, so incandescent is the way to go. Efficiency and extreme long life just don't matter.
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Chuck(G)
3/30/2012 5:40 PM EDT
Most of the lighting in my house is in the form of recessed ceiling-mounted IC-rated "cans". Unfortunately, most CFL (and I assume, LED) is designed to operate with some air circulation for cooling. In particular, I note that most CFL lighting is designed to "burn base down". I get miserable performance out of R30 CFL reflector flood replacements. In one ceiling, I divided the lamps half-and-half between 65 watt incandescents and the equivalent CFLs. I removed the dimmer because dimmable CFL floods are outrageously priced and very poor in performance. I replaced all of the CFL units three times over the last 5 years; the incandescents are still original.
I'm fairly sensitive to flicker; those LED Chirstmas light strings drive my vision crazy; they're mostly configured as series-strung LEDs in a "self-rectifying" configuration. Horrible, horrible, horrible--the lights look like they're inhabited by crazed ants.
Come up with something cheap, non-toxic and a functional improvement and I'll buy it.
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feepingcreatures
4/1/2012 10:23 AM EDT
What we need here is a new standard for home power supply: a low-voltage DC bus, say 60V, which would be used for lighting and other low-power appliances. AC is essentially pointless once you get down past the 13kV transformer in the street: few of our appliances "need" AC, and most of them have a rectifier right at the front.
With a DC bus in the home, the four problems mentioned would basically go away.
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Firefly Will Return
4/2/2012 6:53 AM EDT
Has anyone ever calculated how much energy/resources are consumed in the manufacture of ALL the components in an LED light? I wonder how much more efficient they really are when this is taken into account.
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katgod
4/4/2012 3:34 PM EDT
I am pretty sure they have in Europe as they are very big on total energy consumption not just end user, they were and maybe still are also more concerned about what the load looks like for the energy provider i.e. the device P.F.
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Kevin.Jackson
4/4/2012 9:53 AM EDT
My plasma TV burns 1750 Watts, and my government is worries about a few incandescent lamps?
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Kevin.Jackson
4/4/2012 9:57 AM EDT
Most of the military products I've designed had to operate at 100 degrees Celsius.
Knowing where these products would be used, I would assume CFLs and LEDs would be designed in the same way.
Are they?
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katgod
4/4/2012 3:30 PM EDT
They mostly come from China and they are sold based on price so I think it is safe to conclude they are not.
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GPBobby
4/8/2012 1:28 AM EDT
60 vdc is still too high for the small number of diodes found in most lamps. Without switching, dc regulators (drivers) are extremely lossy, so we're back to switching regulators. Might as well use ac in the first place. The problem is that inherently the different type of light sources are not all equally suited for every application. It will be years before anyone can come up with a cost equivalent replacement for a 75 watt incandescent for a closet. Let the free market and customer needs, not government edicts and subsidies determine which lamp goes in which socket.
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Maggic
8/17/2012 3:23 AM EDT
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