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LED Evolution Could Spell The End For Bulbs
An anonymous reader writes "USA Today is running a story discussing how LED lamps were unthinkable until the technology cleared a major hurdle just a dozen years ago. Since then, LEDs have evolved quickly and are being adapted for many uses, including pool illumination and reading lights, as evidenced at the Lightfair trade show here this week. More widespread use could lead to big energy savings and a minor revolution in the way we think about lighting."
I know that this is true because I read it in the Bible. They did not evolve, they were created by God.
I guess we are going to start having "illumiphiles" who will try to tell us that the incandescent lightbulbs of yesteryear are somehow "warmer" and that humans can tell the difference between LEDs and vacuum tubes.
an illuminating article...
--- Asking inconvenient questions for over 30 years...
I'd buy them for that capability alone.
I wonder when we might see LEDs with enough brightess to serve as a projector lamp?
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
the lightbulb industry lobbies the congress to ban LED technology that will ruin the market for lightbulbs.
Dvorak on Doomtech
For starters: LEDs aren't as efficient as many people seem to think, iirc they're a bit more efficient than normal lightbulbs, but TL-lamps and other gas-ionisation-type lamps are still way more efficient. Secondly: While LEDs may emit light for 6 years continuously, they have a certain half-life that's way shorter than that; at the end of the 6-year life span, the leds probably only emit 1/4th of what they did when they were new.
I used to think of LEDs as cute little indicator lights. A nice tiny, soft green LED light tells me that my monitor is on, or blinkenlights let me know that packets are flowing through my router. An orange LED might alert me to standby mode on a device. None of them were really all that visible unless I was looking directly at them, and certainly none put out any ambient light.
Then I got my newest computer. This thing has a single blue LED backlighting an area the size of a dime, behind the power button on the case. When I turn off all the lights, after a minute or so of my eyes adapting, the single blue LED gives off enough light to illuminate half the room. For the first week or so, I had trouble getting to sleep because of the light... From one blue LED.
As the technology gets better I can imagine LED lamps coming in vogue. I seriously doubt that the end of the bulb will come anytime soon, though. Probably not in my lifetime.
"BSD: Free as in speech. Linux: Free as in beer. Windows 10: Free as in herpes." --Man On Pink Corner in #52607549.
This is no surprise... it's been this way in flashlights (hand torches, to you brits) for a while, particularly the higher-end ones and those designed for specialty applications.
As an example, some of the weapon-mounted lights being used by the military are also going to LEDs. Some of the regular incandescent bulbs just don't hold up as well to the punishing recoil of most weapons... you were forever changing bulbs. The higher end incandescent lights like the Sure-Fire lights could take the shock, but forget mounting anything like a mag-lite on a weapon.
Best thing about them: they're easy on the batteries. Batteries are heavy, and there's nothing worse than having to carry too many spares. Every ounce counts when you're carrying it on your back.
Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
I'd have to invest in some hardcore lift music to complete the 'still out shopping' effect. And perhaps pay a young relative to scream and be slapped periodically in the middle distance.
www.whitedust.net
"On a very hot day you might want blue light to cool it down a bit."
And if street noise is distracting you, a green LED will quiet that right down.
I've heard of this before, having the odd bluish tone to it, maybe this will help.. I dont know, I dont have a lot experience with leds.
"Q: I want to use white LEDs for photographing or videotaping insects, plants, electronic parts, and other close-up subjects, but all of the white LEDs I've tried have this blue circle in them that ruins the picture. Any suggestions?
A: Try using Nichia's rectangular white model, NSPWF50S. This LED has a very wide, even beam that doesn't have that obnoxious blue ring in its beam. Since all white LEDs tend to have a bluish cast on film or videotape, you may need to adjust your camera's white balance or even use an orange-tinted filter to compensate.
The beam angle is very wide, around 140 by 120 degrees, so they won't be very good much over 1-2 feet away from the subject. They should work great for close-ups (a foot or less) though.
You will probably have to buy these directly from Nichia, since electronics places don't seem to carry them yet. I have some info on my Where To Buy LEDs page. "
Thats from the led musem (find it through google if you want or here ya go
http://ledmuseum.home.att.net/reserved.htm#q7
http://ledmuseum.home.att.net/ (the led museum homepage.. very cool stuff, he's been around for a long time. check out his rigged up wheelchair.)
Someone else here can probably provide an explanation for why there's a bluish tone to some white leds.
I think one of the main issues with LED lights is the incompatibility with existing lamps.
Sure you buy new lamps every once in a while, but a real breakthrough will come when you can get LED 'bulbs' that fit in a normal 220/110V socket on a normal lamp.
The same thing happened with those energy-saving bulbs, it seems they only really took off (at least here in Denmark where electricity is expensive) when they became available in versions that looked like normal bulbs and fit most lamps.
Another example is the wire spot halogen lights, once they became available in 220/110V versions they took off. Nobody seemed to want those bulky 220->12V transformers around.
Unfortunately, like the article says, the first cost is still prohibitive in a lot of cases, although the savings in energy would seem to make it worthwhile. LEDs also tend to get very, very hot in large quantities if they're used for a long period of time, so air circulation is a common problem as well.
Hopefully some of you computer engineers and programers can come up with a cheap way to produce and control LED arrays so I can start using them in practice! Building owners would be extremely happy if power consumption in buildings would go down significantly and if they had the ability to control the color and brightness (they are easily and cheaply dimmable, unlike flourescents) of any room individually.
This article contains material on evolution. Evolution is a theory, not a fact, regarding the origin of living things (and light sources). This material should be approached with an open mind, studied carefully, and critically considered.
A big advantage of LEDs over standard lightbulbs is, that they are quickly switchable without reducing lifetime that much. For lightbulbs you need expensive flashlights, but for LEDs a standard 5mm High Power LED - or if you want more power, a flux - can be used for fast switching applications.
,-).
Additionally you can use many LEDs together without much effort to create nice structures and designes in different colors - as mentioned in the article.
Since I discovered not so long ago, that the blue and white LEDs of today with e.g. 8000 and 20000mcd are another dimension compared to the LEDs I used in my electonic experimenting set as a child, I hacked together an XMMS-Plugin serial lightshow with a uC-backend and use some blue and red high-power LEDs to illuminate some parts of the room. With standard lights that fast-switching beat-detection would not be possible in such a cheap way.
Of course if you really want to illuminate the room in a standard, really bright manner, you need even more powerful and expensive LEDs, however it is a good start and I expect my main, ordinary illumination to be "lightshow compatible" in 10 years
--- censored
So which way am I better off? Just using lower wattage "classic" lightbulbs, or with dozens of 120V AC->5V DC converters wasting energy everywhere.
The adapter for my iBook puts out more heat then the iBook. More of the heat from my AMD64 is from the power supply vs. the CPU and Gfx.
Almost nothing I own needs over 12V anymore. When will I be able to just have one nice 120->12V spaceheater and run everything else in the room off 12V?
- Adam L. Beberg - The Cosm Project - http://www.mithral.com/
They haven't been used as sources of illumination because they, for a long time, could not produce white light -- only red, green and yellow. Nichia Chemical of Japan changed that in 1993 when it started producing blue LEDs, which combined with red and green produce white light, opening up a whole new field for the technology.
This is certainly one way to produce a white LED but it is not the common method today. Most white LEDs use a phosphor to convert a blue or ultraviolet LED into a white one. A quick google found the following page that talks about this in more detail:
http://www.marktechopto.com/engineering/white.cfm
I would speculate that for normal home lighting using a phosphor will give better results as:
Just this week, researchers at the Lighting Research Center at Rensselaer Polytechnic Institute in Troy, N.Y., said they had boosted the light output per watt of a white LED to almost six times that of an incandescent light bulb, beating even a compact fluorescent bulb in efficiency.
The drag racing industry has moved from incadecant to LED lights for the starting "Christmas Tree"
Introducing Microsoft Vacuum 1.0 The first Microsoft product that doesn't suck.
I thought white LEDs are usually blue LEDs, which are coated with a scintillator, which converts parts of the blue light to yellow. Wikipedia seems to support my impression.
Regarding efficiency, I refer once more to Wikipedia: "In 2002, 5-watt LEDs were available with efficiencies of 18-22 lumens per watt. [...] In September 2003 a new type of blue LED was demonstrated by the company Cree, Inc. to have 35% efficiency at 20 mA. This produced a commercially packaged white light having 65 lumens per watt at 20 mA, [...]".
"Between strong and weak, between rich and poor [...], it is freedom which oppresses and the law which sets free"
Q: "How many Californians does it take to resolder an LED?"
A: "Californians don't resolder in LEDs. They resolder in hot tubs."
One can only pray for a GFI failure.
Q: "How many trailer trash rednecks does it take to resolder an LED?"
A: "They still use lightbulbs!"
Okay, that one's still okay.
This is not my sandwich.
Dude, six years is forever in the tech world. Six years is long enough for everybody to want to replace whatever they have with something that is both cheaper and vastly better, even LEDs.
"OH SHIT, THERE'S A HORSE IN THE HOSPITAL!"
Warm and cool are really terms used to describe white light. When you talk about white the question becomes what is it? A blend of all the colours is an elementary explination, but the fact is they aren't all present in equal levels, from any source.
The way that it is talked about, is called colour temperature, and it is spoken of in kelvins. The idea is if you heat a black body radiator to that temperature, that's the kind of white you get. The lower the temperature, the more red in it, the higher the temperature, the more blue.
On most monitors that aren't connected via DVI, you can see colour temperature changes for yourself. In its configuration there should be a colour temperature option, generally with three presets: 5000k, 6500k and 9300k. PLay with them and notice the change. You'll probably find that changing from the one you are used to looks "wrong", either too red or too blue depending on. That's an illusion, however. If you go away for awhile and come back, or just ignore it and keep working, you'll find your eyes adjust and consider that to be white.
With bulbs, it gets more complex because it's not just a function of the temperature of the white, but of it's spectral composition. Most incandesant bulbs have a spectrum that is low on the high frequencies (near violet) and high on the low frequencies (near red). Other lights, like many floursecants, have an uneven spectrum, with peaks all over.
Now ideally what you are shooting for usually is light as close to sunlight as you can get. That's what humans would generally think of as "normal" or "correct" lighting. Easier said than done, of course.
So I don't know what the spectrum for any of the varities of white LEDs looks like, but it is very possible, even likely, that they are different than an incandescant bulb. It may be that they have a generally higher temperature and thus really are cooler, colourwise.
The first white LEDs were an RGB mix to produce white; now they use blue + scintillator, probably producing the blue circle. I'd imagine with better diffusion methods this could be overcome.
Anyone notice that a blue LED has a 'haze' around it when looked at from the side (i.e. not looking at where the light comes out)? This is even more pronounced in purple LEDs (which are still expensive and not ready for commercial use). Wonder if this haze has anything to do with the blue circle appearing on recordings...
"I think it would be a good idea" Gandhi, on Western Civilisation
Not entirely true. LED lights are fully legal if they don't flash, that's all there is to it. There are laws that predate LEDs on having flashing lights on vehicles. This was a minor news article when flashers first appeared, but many prominent figures came out and said they would pay for any fines should someone get in bother for having something that clearly improved their safety.
I don't think anyone has actually been prosecuted for it. So, what we are basically seeing what is a new "stupid law" that never gets enforced. Kinda like the one that states that taxi drivers must always carry a bale of hay, and that they can legally urinate in a public street provided they pee on their back wheel!
Mostly true. When viewed directly, the eye perceives any color in the color space defined by the three LED colors. But the actual light is still trichromatic, so it won't light up the objects in the room the way you expect them to. A beautiful yellow light might make an object of that same beautiful yellow look like a dingy brown, becuse there's no actual light of that color to reflect off the object.
Try it yourself: Tonight, set your screen background to various colors, turn off the other lights in the room, and see what things look like when lit only by the monitor. The effect isn't as pronounced, but it's still observable.
I have an interestiung anecdotal from ye olden days. Way back when, I had a girlfriend who was an artist, and going to an art school. They had a black tie affair for the students faculty and parents,so we went. Hey, free food and champers! Me in a tux, too funny! Anyway, one of the students mom's there lost a diamond out of a setting, fell on the floor someplace. So here's a couple dozen people in gowns and tuxes all bent over squinting at the floor. We saw it, went over to ask "what's up"? Got told about the loose stone, girlfriend glanced down, immediately spotted it, went over and picked it up, like one second. She saw it from her extraordinary ability to see colors. She had been tested in the school and won, ran 10,000 colors in ROYGBIV sequence not missing a single shade, the only student to get all of them correct.
There are also more subtle issues at work with the 'R/G/B mixing' approach to colour generation. You can read more about them here.
To summarise; consider that the red, green and blue receptors are sensitive to a *range* of colours; the sensitivity curve for each receptor is roughly bell-shaped, peaking on red, green or blue light. There is also some overlap between the red and green sensitivity curves, and between green and blue (not red and blue IIRC).
This is of course essential. Sensitivity narrowly focused on R, G or B would leave us unable to see intermediate colours (e.g. yellow!).
Reasonable overlap is necessary, or
(A) there would be certain intermediate frequencies that were not covered sufficiently by either receptor (e.g. certain shades of yellow in the valley between the red and green curves would be very hard to see), and
(B) Colours would be quantised into 'red group', 'green group', or 'blue group' (think about it...)
Because of the (necessary) sensitivity-curve overlap, the green receptor is slightly sensitive to red light, and so on. Where is this leading, you ask?
True cyan has a frequency between blue and green. This is within the sensitivity range of both blue and green receptors; the brain can use the 'ratio' to figure out that it's looking at cyan. But true cyan is (to all intents and purposes) outside the red receptors' range, so the red receptor is not stimulated.
Simulated cyan is made up of green and blue light. This stimulates the green and blue receptors in the same ratio as true cyan would, so in theory looks just like the real thing. However, the red receptor is also slightly sensitive to green light; thus, unlike with real cyan, the RGB-mixed version also stimulates the red receptor.
This is (supposedly) what makes certain RGB-generated colours less convincing (hence the linked story above).
This isn't even counting the fact that our colour receptors aren't exactly R, G and B, and therefore to simulate certain colours using RGB is impossible, as it requires one or more components to be negative. (If the receptors were exactly R, G and B, that would not be the case).
"Slashdot - News and Chat Sites Deviant". (Click "homepage" link above for details).
It will be some years before we reach this tipping point in price however as current costs are about $100-$200 a bulb for 65watt equivalent LED bulbs
10 years after most bulbs are LED conventional bulbs will seem anachronistic and stone age. One of the few things in the last 100 years to just be out and out replaced by a new technology. Granted we have lots of bright shining new things in our modern world, but they general have been added to what we already have or evolved slowly from what came before. The switch to transistors from tubes is about the only other thing that comes to mind where this has happened, and perhaps this should just be seen as one of the last hold outs of filaments in tube to be displaced by solid state. All that is left to go are CRTs and this too will happen relatively soon.
In need of a similar revolution: Cars that run without gas - this is a hard one, but we are finally starting to make some progress; Energy production from other than Oil, Gas, Coal, and Uranium. Fusion is about the only way to go here, but it isn't doable at any price today. None of the other energy alternatives have a chance of displacing the big 3 fossil fuels or remaining conventional nuclear plants; Getting to Space without conventional rocket technology. Do all these things and we will have finally arrived in the 21 Century.
Letter To Iran
I think all the new stoplights in town are LED stoplights. Most of the brakelights on trucks around town are too. Did this story fall through a time-rift from seven years ago?
What other lights?
I doubt it, at least not the kind of person the grandparent is referring to. If you are you should be calling a research lab and asking for bids to be a guinea pig. Tetrachromats are extremely rare.
This hypothesis sounds more likely (from http://www.physics.utoledo.edu/~lsa/_color/18_reti na.htm
Rods and all three cone types readily absorb ultraviolet radiation, photons of which are energetic enough to damage these delicate cells. The reason we cannot see in the UV is because the eye lens is opaque in that wavelength range. In addition, the cells in a region called the macula surounding and including the fovea contain a yellow pigment that further prevents short wave radiation from reaching the photo-receptors. Some people with less of this yellow pigment and those who have had their lenses replaced with plastic inserts can see further into the UV than normal people can.
Without power, many people seem to turn into hopeless wrecks.
People burn their entire supply of toxic paraffin candles in about two days, (if they have them), they run out of food, and they start to freeze. If the power had gone out for more than a couple of weeks without emergency help or without a shift in how people arranged their lives, I think we'd have seen some serious Darwinism in effect. --Luckily, when people get motivated, they also tend to be quite resilient; two weeks without power is like getting kicked out of bed. "Okaaay. Fine. I'll go do something about the situation rather than gripe and eat all the easy food."
But anyway. .
I found myself hurting for a decent lighting solution. With no power, and time to kill, people like to read and they play social games like D&D! Except, without reliable lighting, these things are possible only during the daylight hours, (which in the winter time are in shorter supply, plus if you have your windows covered up with blankets for extra warmth, the lighting situation isn't so good). --And a room filled with paraffin wax smoke gets toxic and trippy in a bad way after about half an hour. Yuck. --Bees wax burns non-toxic and smells really nice, but those kind of candles are usually expensive and in short supply.
Enter the LED flashlight! After the power out-age I ordered a 'Lightwave 4000'. It runs on 3 D-cells, and you can expect about 900 hours of solid run time. (2000 hours, if you believe the packaging, which I don't.) Still, 900 hours is 37.5 days of solid 'On.' Cut that in half for night time use only, and you're looking at over two months of lighting on 3 batteries. That's 9 batteries to last you all through winter. Not bad!
Then just toss in a few of those small, $10 Dorcy single-LED lights which run on AAA cells for 200 hours or so. --Keep those in supply, and you're fine. --For a social setting, just set up a Bee's wax candle to throw a little nice color, and you're surviving in style.
Wrap up in blankets, get an alcohol burner for teas and soups, or better, a wood stove, and you're laughing. Life is fun when you're prepared!
-FL