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Brighter LEDs pave the way for a new type of home interior lighting

The LED, or Light Emitting Diode, has been around since the late 60’s but only over the last few years have LEDs made headway into commercial mainstream use.

Some new vehicles now use LED’s in headlights and taillights. The benefits of this are brighter light and much improved life span for the bulbs. Some stop lights also use LEDs to combat against the hazard of a stop light burning out.

Of more interest to technophiles is the advent of LEDs for use as backlighting in our notebook computers, such as the recently announced Dell Latitude XT tablet PC, and other personal electronic devices. LEDs promise less power consumption in out notebooks thereby increasing battery life. LEDs are also slowly making their way into our flat panel TVs such as the Samsung 31-inch OLED panel DailyTech reported on last week.

Scientists also have their eye on LEDs for use in the home to replace the incandescent and florescent light bulbs. The big benefit for consumers to using LED lighting in the home is much greater lifespan and less power consumption.

While some scientists are hard at work on methods to add more natural spectrums to current LED lights, other scientists announced a breakthrough last week to help defeat the problem with low light output from
LEDs.

A new method for increasing the light output from LEDs involves a process called nano-imprint lithography. Scientists at Glasgow University along with the Institute of Photonics at the University of Strathclyde invented a process that makes millions of microscopic holes on the surface of a LED bulb, which increase the amount of light the LEDs give off.

Project leader Dr. Faiz Rahman who told the BBC, “As yet, LEDs have not been introduced as the standard lighting in homes because the process of making the holes is very time consuming and expensive. However, we believe we have found a way of imprinting the holes into billions of LEDs at a far greater speed, but at a much lower cost."

According to Rahman the days of the humble light bulb may soon be over.


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Excellent find
By maverick85wd on 1/1/2008 11:45:14 AM , Rating: 2
quote:
LEDs are also slowly making their way into our flat panel TVs such as the Samsung 31-inch OLED pane


Samsung also has LED smartlight technology in their new high-end LCD displays. Unsurprisingly, the ability to control each pixel's brightness gives the display an amazing contrast ratio. Using an LED backlight reduces the power consumption by roughly 30% as well.

LED lighting in homes and businesses is an excellent way to increase the world's lighting efficiency. Hopefully that time is soon! There's something about the light a compact florescent bulb gives off I don't like, I wonder how close to natural sunlight they can get with LED's. I hope this brings the price down quite a lot, because right now LED home lighting options are QUITE pricey.

http://www.besthomeledlighting.com/




RE: Excellent find
By Hare on 1/1/2008 12:09:48 PM , Rating: 2
Power consumption depends on many factors. Samsung Syncmaster XL20 LED display actually has a fan because it draws so much power ("Uses twice as much power as similar size CCFL-backlight LCD monitors" - Silentpcreview.com).

Of course this was just one example. Usually LED displays consume less power than normal LCD monitors e.g. macbook pro.


RE: Excellent find
By maverick85wd on 1/1/2008 12:15:24 PM , Rating: 2
I was referring to that particular line of displays... apparently they use roughly 30% less power than similar displays with CCFL backlighting.

Interesting point though, I wonder why certain LED displays use so much power


RE: Excellent find
By maverick85wd on 1/1/2008 12:41:22 PM , Rating: 2
also, forgot to say, just because it gets extremely hot doesn't mean it won't use less power
quote:
actually has a fan because it draws so much power

... one of the problems with first incandescent bulb replacements was heat... they had to make the shape of the bulb a giant heat-sink and there was a small circuit board with LED's on it in the middle. It used 2W and brightness was similar to a 60W bulb, which gets hot but obviously not hot enough to need a heatsink or fan. I would give a source, all I remember is that it was either a Popular Mechanics or a Popular Science magazine from 2006


RE: Excellent find
By Hare on 1/1/2008 1:23:45 PM , Rating: 2
quote:
also, forgot to say, just because it gets extremely hot doesn't mean it won't use less power

Energy doesn't appear from thin air so if a monitor gets hot it definately consumes power to create that heat. If you have display A that consumes 20W and display B that consumes 80W you can bet that the B display releases 4 times more heat -> 4 times more power hungry.


RE: Excellent find
By Basilisk on 1/1/2008 2:38:36 PM , Rating: 3
While you are both "right", you seem to be missing his point that the early LED bulb-replacements got too HOT. In general use, "hot" means the package surface temperature is high, but rarely indicates the total dissipated POWER. E.g.: a 14-watt candelabra bulb gets much "hotter" than an electric blanket drawing 40 watts (you -hope-!); likewise a 40 watt florescent bulb has so much surface area it's nearly cool while a 40 watt incandescent bulb is HOT.

Incandescent bulbs send a significant amount of their heat down the filament into their base and into house wiring; those first LED "bulbs" didn't, so the LEDs had to *radiate* a much higher portion of their generated heat, IIRC. I don't remember if they also had a smaller envelope (glass bulb) or anything else that also would raise the surface temperature of the package.


RE: Excellent find
By maverick85wd on 1/1/2008 3:03:15 PM , Rating: 2
quote:
Energy doesn't appear from thin air so if a monitor gets hot it definately consumes power to create that heat


I am not disputing this point. The heat has to come from somewhere, and it is definitely a by-product of energy consumption. However, this doesn't mean that the relationship between energy consumption and heat production is direct when comparing different technologies.
quote:
LEDs produce very little amounts of heat; the heat noticed in some instances is due to on board components and other factors of the circuit. In comparison to incandescent, LEDs produce a fraction of the heat. If LEDs are hot to the touch, they are being overpowered due to improper circuitry.

http://www.sailboatstuff.com/co_sailboatstuff_LED_...

So basically using LED back lighting is more energy efficient than CCFL's, that other display needed a fan to cool the accompanying electronics which is also where the extra energy was spent.


RE: Excellent find
By Hare on 1/1/2008 4:14:24 PM , Rating: 2
quote:
However, this doesn't mean that the relationship between energy consumption and heat production is direct when comparing different technologies.

Let me put it this way. Since energy in = energy out. What other form of energy does the display put out other than heat?

I'd say that power consumption / released heat ratio is pretty direct. 99,99% of the energy consumed by a display is released as heat.


RE: Excellent find
By Jedi2155 on 1/1/2008 8:50:31 PM , Rating: 2
Light.


RE: Excellent find
By maverick85wd on 1/1/2008 9:07:50 PM , Rating: 2
excellent!

I was painstakingly painting him a picture in a comment and saw that you had beat me to the punch... and said everything I was trying to get at with one word. Brilliant!

Imagine that! Displays emit light as well as heat!


RE: Excellent find
By SlyNine on 1/2/2008 12:13:50 AM , Rating: 2
I thought the point of LED's were they produced light without produceing heat. So it just depends on how efficent it is. Less so it will produce more heat for the watt, more so and it will produce less heat per watt.


RE: Excellent find
By TomZ on 1/2/2008 8:48:18 AM , Rating: 2
No, LEDs do produce heat. And the design issue with LEDs, as another poster noted, is that they may produce a few watts of heat at a very small point (the semiconductor junction) without having any inherent way to dissipate the heat, unlike other types of light sources. Therefore, LED lamp design requires that a heat sinking mechanism be designed in (passive heat sink, fan, etc.).

When compared with other light sources, LEDs are relatively more efficient, but not perfectly efficient.


RE: Excellent find
By Alexstarfire on 1/2/2008 3:55:48 AM , Rating: 2
I think you're confusing a stove, or some other heat source, with EVERYTHING ELSE. Things go produce heat, but unless they are designed to produce heat and nothing else, then it's not a very direct correlation. Let's take an electric motor as an example. An electric motor for a car uses a TON of power, but doesn't emit nearly any heat. Explain that to me then.


RE: Excellent find
By Hare on 1/2/2008 12:53:53 PM , Rating: 2
The engine itself doesn't release all energy as heat but at some point the energy is released as heat. It's quite simple. Electricity spins the engine and some percentage of the energy is directly released as heat and some percentage is "converted" to kinetic energy. Kinetic energy is then converted to heat as the axles, tires etc have friction (unless the car is a perpetual machine).

The actual amount of power that is converted to light is actually quite small compared to heat production.


RE: Excellent find
By PedroDaGr8 on 1/2/2008 9:04:37 AM , Rating: 2
You are confusing heat and temperature. Which, while related, are different. This is something I have a hard time explaining to my students. Adding a certain amount of energy to a substance does not raise its temperature uniformly across all substances for examle adding 1KJ of heat to Brass raises its temperature 380oC while adding the same 1KJ to aluminum raises its temperature 900oC.


RE: Excellent find
By PedroDaGr8 on 1/2/2008 9:12:24 AM , Rating: 2
Also, incandescent bulbs have no temperature limit (within reason) the hotter they get the brighter they shine. While an LED does have a temperature limit at which the semiconductor materials begin to break down. This means that one temperature which is acceptable for a lightbulb is fatal to an LED, hince LEDs must be kept cooler, thereby requiring built in cooling systems instead of relying strictly on internal radiative and convective processes.


RE: Excellent find
By Hare on 1/2/2008 1:07:36 PM , Rating: 2
Exactly. Common LEDs can take around 85C° but incandescent bulbs don't even work below 800C°, I believe (tungsten coil). That is the biggest reason why the display had a fan but the overall power consumption was much larger than similar LCD with normal backlight. Maybe I wasn't very clear. It happens, english is not my native tongue.

Incandescent bulbs have just a 2-3% efficiency. A high-power white LED by Philips Lumileds Lighting Co. has efficiency of 115 lm/W. Still quite far from theoretical "ideal" of 242.5 lumens per watt for white light. So LEDs do produce quite a lot of heat. Most LEDs are far from ultra high efficiency LEDs like the Philips LED mentioned above.


RE: Excellent find
By MrTeal on 1/1/2008 5:48:13 PM , Rating: 2
The purpose of the fan isn't to deal with excessive power usage, it's to deal with excessive heat. A standard 100W lighbulb creates lots of waste (infared) heat, but that's not really a problem for it, the filament can run at 3500K. No fan is needed. With an LED light, the total power input and heat output can be considerably lower, but a fan might be needed, because the maximum junction temperature is 400K.


RE: Excellent find
By dnd728 on 1/1/2008 4:09:28 PM , Rating: 3
Ahem...

OLED has nothing to do with LEDs - these are two completely different technologies, plus OLED does not require any backlighting like LCDs need.

Also, in LCDs you're obviously not putting a LED behind every single pixel or you wouldn't have even needed the LCD mask in the first place...


RE: Excellent find
By maverick85wd on 1/1/2008 4:21:38 PM , Rating: 2
LED or OLED, they are both light emitting diodes. I know they work differently and everything, but the article is on LED's in general. The author is actually who made the reference to OLED's in terms of LED utilization. I was just adding on to his mention of LED usage in large screen displays.

I mis-read, I was scanning it and thought I read that each pixel's brightness was controlled individually but I was wrong. Here is one place I read about it:
http://www.oled-display.info/samsung-f9-led-smart-...


RE: Excellent find
By dnd728 on 1/1/2008 5:09:39 PM , Rating: 2
The author is actually who made the reference to OLED's in terms of LED utilization.
That's true.

I was scanning it and thought I read that each pixel's brightness was controlled individually...
I guessed so. That's what they want us to read... ;)


look at these ppl
By sprockkets on 1/1/2008 12:06:18 PM , Rating: 2
www.ledfolio.com

They make 2'x2' LED panel replacements and more.

I like LED stuff, but I'm not convinced yet about using them for headlamps in cars due to heat issues. Time will tell.




RE: look at these ppl
By adam92682 on 1/1/2008 1:41:42 PM , Rating: 2
I'm sure they dont get as hot as halogen bulbs used in headlights now.


RE: look at these ppl
By melgross on 1/1/2008 4:28:50 PM , Rating: 3
No. Halogens must get hot, or they don't work properly. The re-deposition of metal back onto the filament in a halogen only functions at about 600 degrees F.

LED's get hot because of dissipation, but it's unwanted heat. High power LED's require heatsinking, otherwise their lifetime is short.


LED's are great, but not perfect
By Surak on 1/1/08, Rating: 0
RE: LED's are great, but not perfect
By SlyNine on 1/2/2008 12:37:22 AM , Rating: 2
Their have been tons of documented links between Iraq and the terrorist organizations you just choose to ignore it. No WMDs that you know of, however they are their. As far as our safety, seems we are not the ones being attacked as of late.

The only thing I agree with you about is, whether or not we are causing global warming is not the big issue. The issue is what are we going to do about it. Just sit around until we melt. Whether or not we are causing it we do need to take care of it.


By Alexstarfire on 1/2/2008 4:05:06 AM , Rating: 2
Is it just your hunch that Iraq has WMDs then? I'm not saying that taking out Saddam was a bad idea, but staying there is.


RE: LED's are great, but not perfect
By TomZ on 1/2/2008 8:58:11 AM , Rating: 2
quote:
Their have been tons of documented links between Iraq and the terrorist organizations you just choose to ignore it.

No, you are wrong and are choosing to believe the lies of the Bush Administration. According to many experts and finally concluded by the Sept. 11 Commission, there were no ties between Hussain and Al Queda:

The Sept. 11 commission reported yesterday that it has found no "collaborative relationship" between Iraq and al Qaeda, challenging one of the Bush administration's main justifications for the war in Iraq.
http://www.washingtonpost.com/wp-dyn/articles/A478...

quote:
No WMDs that you know of, however they are their.

Common sense tells us that, since we haven't found any yet in our 4+ years of occupation of Iraq, that there must not have been many there to begin with, right?


LEDs and Heat
By josebl on 1/1/2008 6:05:44 PM , Rating: 3
It's important to remember that the XL series of monitors are marketed as color reference grade monitors. LED efficiency can decrease dramatically with heat. LEDs have a hard time shedding heat. The XL series of monitors as well as Samsungs 81 series of monitors (for the ultimate in this technology see Brightside Technologies or Ecinema's monitors) use local dimming of LEDs which require additional feedback circuitry. For reference see: http://spie.org/x8836.xml?highlight=x2408 which covers a lot of these issues. TIR Systems has also posted a number of very good articles on LED (phosphor coated and multi-color white) design. An old article in Laser Focus world by some guys at TIR did a very nice job of discussing the difficulty of designing "white" LED sources - http://www.lfw-digital.com/lfw/200605/?pg=79. So, assuming that a fan on the XL20 is due to horrendous overall heat may be erroneous. It is there to maintain color accuracy and maintain LED lifespan.

In general when talking about different lighting technologies it's useful to measure them, quantitatively, as lm/W or lumens per watt. If it's converting more energy to light it "should" be wasting less as heat. The package size, namely P/N gap, of an LED is so tiny that the heat that is generated has a hard time dissipating. The escape route for heat is through the conductors. This is, oversimplified, why heat sinks are so important on high flux LEDs.

I remember back around 2000 Luxeon had a roadmap on their site stating that by 2020 they predicted LEDs would be the most efficient lighting technology. That would mean they'd have to surpass sulfur lighting at 170lm/W! At the time I considered it marketing...but with the jaw dropping advances in every aspect of LED lighting technology I'm not so sure the industry won't beat this prediction - see Cree's Xlamp technology for a nice example. Exciting stuff!




SWEET!
By Inkjammer on 1/1/2008 11:32:02 AM , Rating: 2
Brighter LEDS are definitely welcome! Now I can go blind faster from all the neon blue LEDs going supernova in my power buttons.

But in all seriousness, this could be really useful for better low energy, high efficiency public lighting systems. Could go a long way to producing better street lighting, making night driving safer while less of a strain on the power grid (seriously, I've often wondered how many street lights Philly has alone. They can't be cheap to power!).




yay for leds
By agentjka03 on 1/1/2008 2:06:30 PM , Rating: 2
New technologies are good at challenging old technologies. The more challenges there are to the players already rooted into the market, the better it is for the consumer.

Technology will continue to improve, and we'll subsequently receive better products.

So, yay for LEDs.




Low Output?
By GTVic on 1/1/2008 2:45:18 PM , Rating: 2
More light with less power would be an improvement.

Some LEDs already output enough light. Those traffic LED lights are painfully bright after dark.

I wonder which applications still require more brightness and what are the power implications of this technology?

I agree with the other poster that headlights are getting too bright (too much power and hard on the eyes). The automobile industry is still focused too much on engine power and vehicle performance. In watching local automobile TV shows they still focus much more on horsepower, torque, etc than on fuel economy and environmental concerns.




Nice technology...
By vhx on 1/2/2008 11:23:26 PM , Rating: 2
Am I the only one who reads about these new technologies and when I see the word "nano" I automatically think of absurdly high prices? That and the fact you probably won't ever see them in commercial application for at least a decade.




Looking further out
By kiwiiano on 1/1/08, Rating: -1
RE: Looking further out
By TomZ on 1/1/2008 4:49:53 PM , Rating: 4
Your attempt to control at mind control has failed; I just turned on a few extra lights at my home in your "honor."

Seriously, you eco-nuts, enviro-fatalists, and eco-commies are quite funny in your prescription for what "ails us." If you think we should all live in caves again, please go ahead and lead by example. Let us know how that works out for you.


RE: Looking further out
By maverick85wd on 1/1/2008 5:05:49 PM , Rating: 2
while I definitely agree our friend kiwiiano is a little off the deep end, I also think smart energy consumption and minimizing pollution is our responsibility as inhabitants of the planet. Some may not care if their legacies have to endure hardship because of us, I am not like-minded... I hope to leave the world a better place than it was when I got here.


RE: Looking further out
By TomZ on 1/1/2008 5:14:39 PM , Rating: 2
Rational environmentalism is fine with me as well, and I feel the same way as you. I just think it's important to speak up against the eco-commies, especially as they seem to be frighteningly more common these days and their views more widely accepted.


RE: Looking further out
By maverick85wd on 1/1/2008 5:34:04 PM , Rating: 2
indeed, thank you Al Gore. I REALLY do not like that they gave that man a Nobel Peace Prize. In fact, at first I thought it was a hoax. I rented An Inconvenient Truth just to see what all the hype was about 2 years ago and was nauseated with all the Gore propaganda which is literally half the movie. He did none of the research, he was basically just a narrator for a slide show. Disgusting.

I actually received an e-mail that had specifications to Al Gore's house and George Bush's house... Gore's house used outrageous amounts of energy while Bush's house had extensive environment-friendly implementations. I have no idea if any of it was true or not, but it was very well written seemed quite researched. Would be hilarious if it's true.


RE: Looking further out
By Kazairl2 on 1/1/2008 9:46:38 PM , Rating: 4
According to Snopes, that e-mail may be slighty exaggerated (Gore's home uses "only" 12X the electricity of a typical home, not 20X), but it is pretty much true. Al Gore's 10,000 sq. ft. home consumes 191,000 kwh in a year. The typical home in Nashville consumes 15,600 kwh a year. In addition to the electrical consumption, the average natural gas bill for his home averages over $1,000/month. By comparison, Bush's 4,000 sq. ft. Crawford home uses a geothermal heat exchange system for heating and cooling that uses only 25% of the electricity of a conventional heating/cooling system. Bush's home is also designed so that roof runoff and "gray" water from showers is stored in a cistern for watering the trees and gardens. See http://snopes.com/politics/bush/house.asp


RE: Looking further out
By rtrski on 1/2/2008 10:32:27 PM , Rating: 2
Personally I wouldn't mind dimmer cities, if only in the sense of less wasted light directed in the wrong direction, usually up. More compact and correctly focused and shielded sources would be quite nice.

I miss the stars.


RE: Looking further out
By MrTeal on 1/1/2008 6:07:18 PM , Rating: 2
Street lighting doesn't have to be made dimmer, just more efficient. The sodium lamps that are used for street lights have great efficacy, but a huge amount of light is wasted into space because of poor design of the light enclosures and reflectors. I'd hardly consider myself an econut, but the fact I have to travel a couple hundred kilometers to get a good view of the stars because of needless light pollution is more than a little annoying.


RE: Looking further out
By amanojaku on 1/1/2008 10:01:01 PM , Rating: 1
First of all, where are you getting the "80% reduction" value from? Back it up with sources (not one, but many) for people to believe you.

Secondly, as technology improves the chances that we will be living in a dim, low power world gets much slimmer. We're learning to use energy more efficiently, with less conversion waste. And there are sources of energy (the sun, lightning, ocean waves, etc...) that we haven't begun to tap and can't turn off!

Lastly, while I'm a tree-huger there is no concrete evidence that our use of fossil fuels affects the climate. The biggest impact is health-affecting pollution and the fact that we're taking the habitat of wild animals away.

Of course, if you're really serious about what you posted you're browsing the web on your 3Watt OLPC XO-1, right? RIGHT?


RE: Looking further out
By mindless1 on 1/1/2008 10:51:21 PM , Rating: 2
You are correct, but inevitably will have your post downgraded because people don't want to accept that even these great new technologies are not enough to allow them to continue thinking green instead of doing green by not using as much light, as many electronic gadgets, etc.

People want token gestures, that if only they buy LED or CCFL bulbs that suddenly our increasing power consumption, combined with increasing global power infrastructure, will be low enough that we can meet it with renewable, non-polluting resources.

It's not going to happen, we (myself included) want lots of light, to surf the web and drive private automobiles, have a large TV and refrigerator, etc, etc. Everyone keeps thinking more gadgets will save us when the truth is it's the gadgets themselves that are the problem.

This is only the tip of the iceburg, such luxuries are becoming more and more commonplace in less developed nations now, with no end in sight. We have yet to accept that we are a bit privileged in our consumption but once the entire world enjoys this privilege equally, it can't last by just tweaking lights and cars, etc.


RE: Looking further out
By TomZ on 1/2/2008 1:15:45 PM , Rating: 2
No, the post was downrated because it makes no sense. There is no current or future global environmental crisis which could/would/should cause us to live in the dark as and give up so-called "luxuries" like "private automobiles" as the OP and you have suggested. The argument for that makes no sense in any way.


RE: Looking further out
By mindless1 on 1/3/2008 3:32:25 AM , Rating: 2
NObody said live in the dark, but there is a more conservative route if we focus on actual energy not "can we reduce what we use without changing our standard of ilfe".

The false premise is that the standard of life built upon wasting energy, should stand.

Also, I understood the post, the sense in it. Did you reread it?


"So if you want to save the planet, feel free to drive your Hummer. Just avoid the drive thru line at McDonalds." -- Michael Asher














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