What is the Future of LED's

mbt25

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What is the Future of LED\'s

What do you think will be the next big advancement with LED's? Could it be increasing output far past the 5 watters? How much can they improve the efficency? Or will it be something completly different? /ubbthreads/images/graemlins/icon3.gif
 

SJACKAL

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Re: What is the Future of LED\'s

I think battery technology affects flashlites advancement also.
 

bindibadgi

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Re: What is the Future of LED\'s

I think that 100% efficiency for a white LED works out to be around 200 lumens/Watt. Right now the good ones run at about 30 lumens/Watt I think.
 

Mgz

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Re: What is the Future of LED\'s

[ QUOTE ]
SJACKAL said:
I think battery technology affects flashlites advancement also.

[/ QUOTE ]

It takes 18 months to double the frequency of the CPU but it takes 50 years to double the capacity of the battery. /ubbthreads/images/graemlins/sick.gif

AFAIK/IIRC the closest future is 2007.
 

jtr1962

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Re: What is the Future of LED\'s

[ QUOTE ]
bindibadgi said:
I think that 100% efficiency for a white LED works out to be around 200 lumens/Watt. Right now the good ones run at about 30 lumens/Watt I think.

[/ QUOTE ]

That depends upon the spectrum. I read that 400 lm/W at a CRI of 80 is possible by choosing the right three colors to mix. By using five colors you can achieve over 320 lm/W with a CRI of 98. I've heard of 50% conversion efficiency being a goal by 2012. That would give us luminous efficiencies of 150 to 200 lm/W depending upon the CRI. There is no technical reason why we couldn't eventually achieve conversion efficiencies approaching 100%. The higher the efficiency the less heat must be dissipated. At 90% efficiency you can run an LED at 10 watts and you'll only need to get rid of 1W of heat (the other 9W will come out as light). Theoretically, this 90% efficient 10W LED could put out over 3500 lumens.

30 lm/W sounds about right for current average production LEDs. Nichia has some new LEDs that run from 40 to 50 lm/W coming out this summer, and the better Luxeon bins run around 40 lm/W.
 

SJACKAL

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Re: What is the Future of LED\'s

[ QUOTE ]
Mgz said:
[ QUOTE ]
SJACKAL said:
I think battery technology affects flashlites advancement also.

[/ QUOTE ]

It takes 18 months to double the frequency of the CPU but it takes 50 years to double the capacity of the battery. /ubbthreads/images/graemlins/sick.gif

AFAIK/IIRC the closest future is 2007.

[/ QUOTE ]

Oh well, at least all the CR123 lights won't get obsolete that fast.

It feels better to know that when you spend like 200 bucks on a flashlight knowing that many years down the road it will still be one of the best and retains it worth. Unlike comparing to computer and mobile phone technologies.
 

mbt25

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Re: What is the Future of LED\'s

[ QUOTE ]
SJACKAL said:
[ QUOTE ]
Mgz said:
[ QUOTE ]
SJACKAL said:
I think battery technology affects flashlites advancement also.

[/ QUOTE ]

It takes 18 months to double the frequency of the CPU but it takes 50 years to double the capacity of the battery. /ubbthreads/images/graemlins/sick.gif

AFAIK/IIRC the closest future is 2007.

[/ QUOTE ]

Oh well, at least all the CR123 lights won't get obsolete that fast.

It feels better to know that when you spend like 200 bucks on a flashlight knowing that many years down the road it will still be one of the best and retains it worth. Unlike comparing to computer and mobile phone technologies.

[/ QUOTE ]

Yeah and when was the last time your flashlight crashed or would only work in certain areas /ubbthreads/images/graemlins/wink.gif
 

SJACKAL

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Re: What is the Future of LED\'s

[ QUOTE ]
mbt25 said:
[ QUOTE ]
SJACKAL said:
[ QUOTE ]
Mgz said:
[ QUOTE ]
SJACKAL said:
I think battery technology affects flashlites advancement also.

[/ QUOTE ]

It takes 18 months to double the frequency of the CPU but it takes 50 years to double the capacity of the battery. /ubbthreads/images/graemlins/sick.gif

AFAIK/IIRC the closest future is 2007.

[/ QUOTE ]

Oh well, at least all the CR123 lights won't get obsolete that fast.

It feels better to know that when you spend like 200 bucks on a flashlight knowing that many years down the road it will still be one of the best and retains it worth. Unlike comparing to computer and mobile phone technologies.

[/ QUOTE ]

Yeah and when was the last time your flashlight crashed or would only work in certain areas /ubbthreads/images/graemlins/wink.gif

[/ QUOTE ]

I guess the areas where they won't work is where there is bright daylight. /ubbthreads/images/graemlins/cool.gif
 

PeLu

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Re: What is the Future of LED\'s

[ QUOTE ]
jtr1962 said:
That depends upon the spectrum. I read that 400 lm/W at a CRI of 80 is possible by choosing the right three colors to mix. By using five colors you can achieve over 320 lm/W with a CRI of 98.

[/ QUOTE ]

It depends what you define as 'white' light, the CRI is not the best scale for it (as mentioned zillion times in other threads). Usually the theoretical maximum for white light and photopic vision is rated around 200lm/W.
When you remove the upper and lower parts of the spectrum you may get higher, but then you just can't see some colours correctly.
If you are happy with a monochromatic light, you could get 700lm/W.
5W luxeons can hit 65lm/W when driven at lower currents (a few mA).
When white LEDs hit the market in 1996 it was said that they will get to 50lm/W in two years. Any mayn other stements like that since then. So I learned not to trust them too much .-)

[ QUOTE ]
Mgz said:
It takes 18 months to double the frequency of the CPU but it takes 50 years to double the capacity of the battery.

[/ QUOTE ]

Take rechargeables (for example): An AA rechargeable had 450mAh 25 years ago, nowadays 2.6Ah are best ones I have. Almost six times (the older numbers my have been more honest).
If you compare them with Li-Ion cells, the difference is even higher.
IIRC, a 18650 NiCd cell had some 800mAh at this time, giving less than 1 Wh, now we are at 2.67 Ah at 3.7V, almost 9.9Wh, more than 10 times as much. And this for a much lower weight.
 

L3

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What is the Future of LED\'s

As I, Nostralumus, gaze into my crystal ball, I see interesting new LED developments appearing on the forthcoming threads of time.

1. Electronically tunable emission wavelengths.
2. Electronically variable solid angle of radiant emission.
3. Heretofore unprecedented levels of high luminous power.
4. Large surface area emitters.
5. Liquid LEDs.
6. LED paint.
7. Thermoluminous LEDs.
8. MEMS LEDs.

The images are starting to fade, and it is time for me to return to the Pyramids of Atlantis. /ubbthreads/images/graemlins/smile.gif
 

liquidium

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Re: What is the Future of LED\'s

[ QUOTE ]
....nowadays 2.6Ah are best ones I have.

[/ QUOTE ]

Hmmm. What brand are those? Best (theoretical) capacity I've seen so far for AA nimh is 2400 mAh Power 2000, but I doubt event those outperform my Energizer/Sanyo 2300s.
 

idleprocess

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Re: What is the Future of LED\'s

There are all sorts of patents out there for new ideas in LEDs... I know a guy that has a patent on printed LEDs - he just needs some access to a clean room and some basic chip fab equipment to perfect the process.
 

jtr1962

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Re: What is the Future of LED\'s

[ QUOTE ]
PeLu said:
It depends what you define as 'white' light, the CRI is not the best scale for it (as mentioned zillion times in other threads). Usually the theoretical maximum for white light and photopic vision is rated around 200lm/W.
When you remove the upper and lower parts of the spectrum you may get higher, but then you just can't see some colours correctly.


[/ QUOTE ]
That's true of course. While I think decreasing the efficiency from a theoretical 400 lm/W with a CRI of 80 to 320 lm/W with a CRI of 98 is worthwhile, I'm not so sure aiming for a CRI of 100 is worth the additional decrease in efficiency of close to 40% except for lighting intended for very critical work. Most people are hard pressed to tell the difference between a CRI of 90 and one of 100, let alone between 98 and 100. However, I definitely notice that lighting with a CRI of 80 seems lacking. I'm not so sure if 80 should be considered suitable for general lighting. For utility areas and streets it is certainly fine, but I think 95+ should be the goal for lighting in our homes, stores, and restaurants.

As for efficiency, who really knows where we'll end up and when. Efficiency isn't increasing as rapidly as first hoped, but then again with any new technology often the pace of development is often overestimated. As an aside, similar high hopes were held for thermoelectric refrigeration 40 years ago. I forgot the exact goal (it was several times higher than existing devices), but the researchers felt it would be reached within five years. Fourty years later we have devices which are only maybe 35% more efficient, and that is due mostly to manufacturing improvements. While I have little doubt we'll eventually have solid-state light sources close to 100% efficiency, the real question is will it be in ten years via a breakthrough or in fifty via slow process improvements? I also think the concept of a light source emitting at a single color will become obsolete long before then. We'll likely have lamps with emitters centered at several (three to five) frequencies. Using feedback you'll be able to make the lamp put out white light at any color temperature you desire, plus possibly almost any color of the rainbow.
 

PeLu

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Re: What is the Future of LED\'s

[ QUOTE ]
jtr1962 said: While I think decreasing the efficiency from a theoretical 400 lm/W with a CRI of 80 to 320 lm/W with a CRI of 98 is worthwhile, I'm not so sure aiming for a CRI of 100 is worth the additional decrease in efficiency of close to 40% except for lighting intended for very critical work. Most people are hard pressed to tell the difference between a CRI of 90 and one of 100, let alone between 98 and 100.

[/ QUOTE ]
Again, the CRI is not a good value IMHO, there are incandescents with an CRI of 100 which are way behind a LED with 85 regarding the 'whiteness' of the light.
If your light just lacks the wavelengths you need, it is not very good.
I know a person who used or maybe still uses a single amber Luxeon for real hardcore caving and is happy with it. He works a Phillips (one of the Luxeon partners) and got a prototype several years ago and gets some 40lm/W.

[ QUOTE ]
liquidium said:
[ QUOTE ]
....nowadays 2.6Ah are best ones I have.

[/ QUOTE ]

Hmmm. What brand are those?

[/ QUOTE ]

As it is completely off-topic, I keep it short and will not pollute the thread with any more data.
They are chinese IMAX (yes, exactly like the cinemas) and give in between 2530 and 2560 mAh according to a friend (I have not teste yet).

Edit 3rd September: It turned out that this friend mistook the charge capacity for this value!
 

jtr1962

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Re: What is the Future of LED\'s

[ QUOTE ]
PeLu said:
Again, the CRI is not a good value IMHO, there are incandescents with an CRI of 100 which are way behind a LED with 85 regarding the 'whiteness' of the light.
If your light just lacks the wavelengths you need, it is not very good.

[/ QUOTE ]

I agree that CRI is not a very good measure. A better measure in my opinion is the so-called full-spectral index (FSI). Basically this measures the deviation of a light source's spectrum from a spectrum comprised of equal energy across the entire visible range. A lower value is considered better, and a value of 0 would be considered ideal. A table of the FSI values for various light sources is shown here. Yes, despite incandescent having a CRI of 100 you can see how poorly it fairs under the FSI index. It isn't just not having certain wavelengths that makes a light source poor. Even when all wavelengths are present (as with incandescent) if those wavelengths aren't balanced once again the light source can be considered poor. The FSI yardstick seems to agree well with my own perceptions regarding light sources. Those light sources with a high FSI (incandescent, warm white fluorescent, and sodium vapor) are exactly the ones I can't stand the most. For example, even a cheap cool white tube (the GE F15T8) with a CRI of 62 fairs better (FSI=1.79) than a 60W soft white incandescent (FSI=7.69). I certainly hope that FSI makes it into common usage as I feel it conveys more information in one number than CRI and CCT convey in two.
 
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