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Are LEDs the light source of the future?

C

CallTheFBI

Banned
I read an article about LEDs as being the light source of the future. Anyone hear anything about this? It said that an LED panel (I guess the equivelant of a couple flourescent tubes) for an office costs $1,000 but it lasts a long time and it uses a lot less power. Does anyone out there actually own an LED panel, if so does it generate a lot of light?
 
it does last along time, but it doesnt have the effficiency (lumens/watt) of
fluorescents which can be 80/lumens/watt and so are the current champions
from a $ pov.
 
Originally posted by: capybara
it does last along time, but it doesnt have the effficiency (lumens/watt) of
fluorescents which can be 80/lumens/watt and so are the current champions
from a $ pov.
Click to expand...

So why are the LED panels on the market? Surely some businesses have a use for them.
 
Where I lived all the trafic light are being replaced (its been going on for a few years). The new type uses LEDs and lasts longer and consumes less energy. The fact that a LED almost never breaks saves a lot of money du to the reduced maintenance.


 
Was the article on the 'net? Can you reference it?

Anyway, LEDs might be an efficient source of light, but first the manufacturing process must be enhanced so large volumes of high-output LEDs can be made at reasonable prices. Also, I'm not sure what the spectral qualities of the light that LEDs produce are, but it would be interesting to know from the aspect of growing plants (just think, pack a panel of those over your marine reef aquarium instead of metal halides, and you wouldn't have to worry about getting a chiller). 😎
 
Plants need UV and thats tricky to produce using LEDs (the energy of UV is too high). It might be possible in the future but as far as I know there are no UV-LEDs right now. There are low-power laser diods that produce light in the right range but they are still too expensive.
 
Originally posted by: jliechty
Was the article on the 'net? Can you reference it?

Anyway, LEDs might be an efficient source of light, but first the manufacturing process must be enhanced so large volumes of high-output LEDs can be made at reasonable prices. Also, I'm not sure what the spectral qualities of the light that LEDs produce are, but it would be interesting to know from the aspect of growing plants (just think, pack a panel of those over your marine reef aquarium instead of metal halides, and you wouldn't have to worry about getting a chiller). 😎
Click to expand...

I wish I could but I can't remember where I actually read it. I think it was in Wired magazine. Sorry.

 
Hm...I remember from some T.V. show that they were replacing regular lights in an office with an array of LEDs placed behind several glass panels in front to spread the light out evenly.

Anyways...I think LEDs are a heck of a lot more efficient than the regular "heat-bulbs" that we use today.
 
i saw some article about an LED flashlight. the guy used a maglite, then took out the bulb, replasced it eith like 18 small LED's. the great thing about it was no circles made by the folds in the glass of the bulb. looked pretty cool.
 
We got the LED traffic lights here in "Silicon Valley", aka Santa Clara county.
They are kind of weird, because from some angles you can't see them 😉
 
White LEDs have a similar efficiency to a decent halogen incandescent light bulb (about 20 lumens/watt). Coloured LEDs are very much more efficient (up to 60 lumens/watt), and even more so when compared to an incandescent bulb and coloured filter. Neither compares to fluorescent lighting (typically 80 lumens/watt, with some systems up to 105 lm/W).

LEDs main advantages are:
long life (potentially 100,000 hours if carefully used) - no need to change bulbs
mechanical robustness (no fragile filaments or glass - the LED crystal is embedded in a solid lump of plastic) - ideal for automotive use
small size - allowing slimmer and more attractive luminaires
near pinpoint light sources allowing very accurate beam shaping - for decorative lights or car headlights
completely dimmable from 0 to 100 % with no change in colour.

White LEDs have a number of problems still:
Life time is not as long as coloured LEDs - the phosphor coating degrades (the best white LEDs last about 60,000 hours - about 8 years 24/7)
Colour quality is poor - much worse than a typical fluorescent light
Wide variability of colour temperature - unlike fluorescents where it is easy to specify closely matched colour temperatures

Some of the latest LEDs are extremely powerful - the most powerful I've come across output about 120 lumens from a single 8mm LED (about the same as a 10 - 15 W mains light bulb). The disadvantage is that they need careful thermal management - with heat spreaders, and possibly even heatsinks. Oh, and they cost $30 each.
 
Another problem with white LEDs is that they do not exist! "White" light is really a mixture of light of different wavelengths (that is why the "color" white is not a part of the spectrum).
A "perfect" LED would only emitt light at a single wavelength, in reality the spectrum is of course broader but it can never be truly white. What we call white LEDs are acually devices that are trying to imitate a light bulb (which basically behaves as a black body) by emitting light at a few diffrent frequencies. This is tricky to do efficently and is one reason why white LEDs are have the problems mentioned above. This is still an active area of research.
 
Originally posted by: f95toli
Another problem with white LEDs is that they do not exist! "White" light is really a mixture of light of different wavelengths (that is why the "color" white is not a part of the spectrum).
A "perfect" LED would only emitt light at a single wavelength, in reality the spectrum is of course broader but it can never be truly white. What we call white LEDs are acually devices that are trying to imitate a light bulb (which basically behaves as a black body) by emitting light at a few diffrent frequencies. This is tricky to do efficently and is one reason why white LEDs are have the problems mentioned above. This is still an active area of research.
Click to expand...

Tell me when they have figured it out because I want some LED panels for my room, I love LEDs that I find in electronics. They never burn out. I'm not going to be spending $1,000 per panel though, I'm not rich (yet anyways). hehe.
 
Originally posted by: Mark R
White LEDs have a number of problems still:
Life time is not as long as coloured LEDs - the phosphor coating degrades (the best white LEDs last about 60,000 hours - about 8 years 24/7)
Click to expand...

What?! Eight years 24/7 is a problem? That is a VERY long time compared to the florescent tubes that offices use today! I'm sorry but I can't hear myself saying: "Damnit! I just replaced this LED panel eight years ago! What the heck is wrong with these things?!"

 
Originally posted by: MainFramed
i could see LEDs being used in homes, cars and just about everywhere.....
Click to expand...


Yes, I have seen car manufacturers using LED's for tail lights and turn signals. They are very bright and probably will never burn out.

 
Originally posted by: f95toli
Plants need UV and thats tricky to produce using LEDs (the energy of UV is too high). It might be possible in the future but as far as I know there are no UV-LEDs right now. There are low-power laser diods that produce light in the right range but they are still too expensive.
Click to expand...

not quite. you can buy uv leds off the shelf:

link

🙂
 
I thought I remembered correctly. I tested both a white light LED and a UV led in a totally darkened room with PNG's (passive night vision goggles). The UV led was amazingly bright but as soon as it was shone on a LCD display you couldnt see it, whereas a normal white led was OK with lcd's but had a lower light ouput
 
The links points to companies selling LEDs with a peak emission at around 400 nm, this is too high to be "real" UV (I don't think you would get a tan). I don't remember the wavelength range of UV A and UV B but it is definitly shorter than 400 nm, 400 nm is violett but it is not really "ultra-violett". I don't think you can not see the type of UV that plants need to grow (the visible spectrum is about 400-700 nm), I also don't know what wavelengths plants like, does anyone else know?
 
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