Flip Chip Opto High Power Build Thread

[Doer]

"I'm trying to help save you some cash. I couldn't stress enough that at this point if I saw 25% on what I was building....'

I can only say Big Picture Planning is a valuable skill. I do this for a living and every day I hear much the same.

People want to jump to the end. The world is full of people that can implement what they know. But, who knows what they don't know? 5 brains are better than one.

My job and what I am doing here, is gaining all kinds of valuable insights, to weigh the framework of the master plan. But, unlike here l tune out (for them, since I like them) all the Read-ahead, do it My Way, Why are we not done? How many times can you change it? Let's just get on with it YAAAAAaaaaaaa...

And as Manager I won't lift a finger to do any actual work, which they know for sure, all the work is done by them.

So, my world is to get a constant stream of praise about how I streamlined the last project into the minimum work. And I get a constant stream of moaning in planning the next project, FROM THE SAME PEOPLE.

And hey, you guys are not doing the work, but you moan pretty good.

This is why I learned a team will not always get along, but, some of the best stuff is thrown out in exasperated sarcasm, at the end of their rope.

 

[Doer]

godless is reduced to pitifullness.

 

[Doer]

You guys have to agree the efficiency just serves a purpose and is not Art, and a goal unto itself, in tech.

Incandescent lighting is less efficient but was all we had.

Candle were not so efficient, but all they had.

 

[Doer]

Lol....... I guess not.

Good luck dude.


(Annnnnd Unsub)


Edit. Only a fool would grant you money to research a less efficient light source than an original fluroescent light bulb. Best of luck.

Well, I know you think I am a fool and are not wishing me luck, so don't disappoint me and come back here.

OK?

 

[Doer]

How efficient is dynamite? A ford truck? A moon rocket?

Not much at first but the real pioneers were not followers. You might recognize this name.

The second most important of Nobel’s inventions was dynamite, in 1867. He coined the name from the Greek dynamis, “power.” The basis for the invention was his discovery that kieselguhr, a porous siliceous earth, would absorb large quantities of nitroglycerin, giving a product that was much safer to handle and easier to use than nitroglycerin alone.

There are 2 Ford F-350 Super Dutys with reported gas mileage parked at Fuelly @ 11.3 mpg

Saturn V had a fuel efficiency to move roughly 4.1 inches to a gallon

All about the choices. Abrams Tank? 1 mpg.

Now we have C-4, Prius, and Solid Fuel Rockets. All much improved. But, if you are in Iraq you pick the Abrams not the Prius.

 

[churchhaze]

You could have a very efficient giant truck or train. Being small does not make a vehicle efficient.

If you're using a giant vehicle to haul around 1 person without any cargo, that efficiency goes wasted on the useless work of hauling the truck's mass around while overcoming friction and air resistance. The truck/train itself could be very efficient at converting chemical energy into mechanical work, but if that work was useless, it may as well be waste.

11.3mpg is not a measure of efficiency. Efficiency is ALWAYS a unitless number between 0 and 1. See the First Law. then see Thermal Efficiency

 

[Doer]

IAC, here what Sylvania has to say about PAR. It is pretty simple really. A photon does the job. The leaves are eating photons. The more photons per mm^2 of leaf the better. Flux density of PAR active photons is not easily related to Lumen, or LER. So, the only reality is to count the density of photons at say 1 square meter. And PAR efficiency has to do with how much watts did you use to land those photons as tightly packed as possible.

Count the photons at the energy range not the energy, is the point. It give a table of conversions.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CDIQFjAC&url=http://www.researchgate.net/publictopics.PublicPostFileLoader.html?id=54636162d3df3e00698b4623&key=d6ddbc4c-5f27-435d-aa16-741e211c110d&ei=YQcGVYWNK4XzoATWzIC4BA&usg=AFQjCNFqT9DZWLbuagTvhPCHp0pecNUG9Q&sig2=P7xQC-GQPigj1EHa8k-IHQ&bvm=bv.88198703,d.cGU
Frequently Asked Questions
FAQ0017-0800
OSRAM SYLVANIA
National Customer Support Center Visit our website: www.sylvania.com
18725 N. Union Street 1-800-LIGHTBULB
Westfield, IN 46074 USA © 2000 OSRAM SYLVANIA
Photosynthetically Active Radiation (PAR) Units
How can I evaluate the effect of different light sources on plant growth?

The Photosynthetically Active Radiation (PAR) measure of radiant power is important in evaluating the effect of light on plant growth. In 1972 it was shown by K. McCree (Agric. Meteorol., 10:443, 1972) that the photosynthetic response correlates better with the number of photons than with energy. This is expected because photosynthesis is a photochemical conversion where each molecule is activated by the absorption of one photon in the primary photochemical process. PAR is defined in terms of photon (quantum) flux, specifically, the number of moles of photons in the radiant energy between 400 nm and 700 nm. One mole of photons is 6.0222 x 1023 photons (6.0222 x 1023 is Avagadro’s Number).

The Photosynthetic Photon Flux Density (PPFD), i.e., the photon irradiance, is expressed in moles per square meter and per second (formerly, Einsteins per square meter and per second). There is not a general conversion factor between photon measurements and energy or light measurements for broad band radiation. However, a specific conversion factor can be determined for a given spectral power distribution, e.g.,a particular light source. This is of practical value because conventional lighting calculation techniques can be used for design of plant growth areas and because color corrected light or illuminance meters can be used to measure PAR values. Some plant scientists want a conversion for the photon flux in the 400 nm to 800 nm band although it is not the standard PAR metric (see CIE Publication 106, Section 8, 1993); this conversion also has been included. Multiply lm/m2 (lux) by the given constant to obtain micromoles per second and per square meter (μmol·s-1·m-2)

To obtain conversion factors from lm/ft2 (footcandles) to μmol·s-1·m-2, multiply the above factors by 10.8

 

[churchhaze]

Design the heat sink around loss.

 

[churchhaze]

And PAR efficiency has to do with how much watts did you use to land those photons as tightly packed as possible.

No, actually, it has to do with with Power out / power in. It has nothing to do with how tight you make the beam.

 

[AquariusPanta]

I think it's safe to say @AquariusPanta will get a research grant for his Frankenstein crown before you get a research grant for your 25% efficient watercooled monstrosities.

Where is AP anyway? AP, come back! lol

I'm back, back from spring break!



LOL @mycrowns

 

[churchhaze]

If you thought the First Law was a buzzkill, you should look into the Second Law.

Damn dude.. Reality sucks!!

The LED god must really suck! I'm having second thoughts about this LED church thing guys.. Am I still allowed to leave? There's too many laws.

Isn't it bad enough we all have to follow ohms law and Kirchhoff laws..?

 

[SupraSPL]

Experimentation and thought experiments for design are useful and encouraged. @Greengenes707 bought a few flip chips to experiment with. I bought a few $6 generic "100w" COBs to experiment on. Almost everyone has a unique design and their own reasons for it. Our knowledge is not absolute, we are just doing the best we can with what we have. We really put our heads together on this, many members have made awesome contributions.

The DIYers here are not dogmatic, we are happy to change our tune when new data or breakthroughs come along. I recall Mr Flux "CXA analysis" thread my first thought was, BAH how could all that power packed in a small space run at a decent Tj? As soon as I reviewed the datasheets, I was eating my hat and extolling the virtues of COB. Scrapped my HPS and built COB flowering lamps. THAT was a major LED breakthrough in output efficiency and cost and it continues to improve at breakneck speed. Cree and Bridgelux seem to be leading the way so far.

IAC, here what Sylvania has to say about PAR. It is pretty simple really. A photon does the job. The leaves are eating photons. The more photons per mm^2 of leaf the better.

True, individual photons drive photosynthesis, but as you increase photon density (PPFD) photosynthetic efficiency decreases very significantly, so many growers look for a happy medium. The curve starts to flatten at about 600 and gets pretty ugly by 1200, although that may vary depending on the SPD, conditions, variety etc.

Flux density of PAR active photons is not easily related to Lumen, or LER. So, the only reality is to count the density of photons at say 1 square meter.

LER is the relationship between lumens and PPF/PAR W, individual for each SPD curve. I agree, it would be convenient if we were also given photon flux data/PAR W, but manufacturers only give us lumen data for white LEDs and occasionally LER. I am sure that will change in the future as LED horticultural lamps continue to increase market share.

For now, we use LER to make comparisons and to estimate PPF/PAR W output. The next step is to use PAR meters to try and estimate PPFD which greengenes has done a lot of and has compared his results with calibrated spectroradiometer readings. I would love to get a hold of one to be able analyze PPFD accurately.

That said, PPFD is not the end point, spectral distribution (SPD) and must also be taken into account. If you have a glut of photons that are all the same wavelength, the plant has to adapt and some photosynthetic efficiency is lost. It is possible to reach a saturation point for a particular wavelength. So it makes sense to try and spread the intensity across the PAR range, as long as we are not sacrificing too much efficiency in the process.

And finally, PPFD is much more effective when spread as evenly as possible. As you can see from photosynthesis efficiency charts, this is a huge factor and another reason why "averaged" PPFD numbers can be misleading.

I figure you probably already know a lot of this stuff already but sometimes it can be helpful to hear it said in different ways.

 

[Doer]

Experimentation and thought experiments for design are useful and encouraged. @Greengenes707 bought a few flip chips to experiment with. I bought a few $6 generic "100w" COBs to experiment on. Almost everyone has a unique design and their own reasons for it. Our knowledge is not absolute, we are just doing the best we can with what we have. We really put our heads together on this, many members have made awesome contributions.

The DIYers here are not dogmatic, we are happy to change our tune when new data or breakthroughs come along. I recall Mr Flux "CXA analysis" thread my first thought was, BAH how could all that power packed in a small space run at a decent Tj? As soon as I reviewed the datasheets, I was eating my hat and extolling the virtues of COB. Scrapped my HPS and built COB flowering lamps. THAT was a major LED breakthrough in output efficiency and cost and it continues to improve at breakneck speed. Cree and Bridgelux seem to be leading the way so far.

True, individual photons drive photosynthesis, but as you increase photon density (PPFD) photosynthetic efficiency decreases very significantly, so many growers look for a happy medium. The curve starts to flatten at about 600 and gets pretty ugly by 1200, although that may vary depending on the SPD, conditions, variety etc.

LER is the relationship between lumens and PPF/PAR W, individual for each SPD curve. I agree, it would be convenient if we were also given photon flux data/PAR W, but manufacturers only give us lumen data for white LEDs and occasionally LER. I am sure that will change in the future as LED horticultural lamps continue to increase market share.

For now, we use LER to make comparisons and to estimate PPF/PAR W output. The next step is to use PAR meters to try and estimate PPFD which greengenes has done a lot of and has compared his results with calibrated spectroradiometer readings. I would love to get a hold of one to be able analyze PPFD accurately.

That said, PPFD is not the end point, spectral distribution (SPD) and must also be taken into account. If you have a glut of photons that are all the same wavelength, the plant has to adapt and some photosynthetic efficiency is lost. It is possible to reach a saturation point for a particular wavelength. So it makes sense to try and spread the intensity across the PAR range, as long as we are not sacrificing too much efficiency in the process.

And finally, PPFD is much more effective when spread as evenly as possible. As you can see from photosynthesis efficiency charts, this is a huge factor and another reason why "averaged" PPFD numbers can be misleading.

I figure you probably already know a lot of this stuff already but sometimes it can be helpful to hear it said in different ways.

Exactly. And we are, at least I am, brainstorming. I do sense natural kindness from most here, expressed in various ways. And here the leaders are not dogmatic but some followers are.

This is a very nuanced subject, that I am pretty familiar with, but the hard science and math is the only way we can get to tech through experiments. Too expensive to just guess. Tech is only trade-offs to make science results useful. The web is literally alive with technical calculators, so I never have to scratch my head too much.

I am most attracted to your white light approach at Kelvin colors instead of spreads of various nanometer emitters. I do think that is more effective at broad spectrum energy. Really up until a month ago I had the same ho hum interest of the last 20 years. But, when @tightpockt told me what you all were up to...wowo. Still, up until a few days ago, I had not idea there was anything like this COB set, from FCO.

I really thank you for the write up. It is exactly what I am seeking. Clarity. And as you point out, these are notes for all, in the future. We are building a reference and a record here.

So, just more nuance, but from what I read LER is weighted for visible human perceived brightness changes, and not for plants. And the reason this seems to be, is the base assumption for LER is based on human comfort.

Just an example I pulled for a Luminarie site.

If you take the theoretical limit for perfect visible white light efficacy as being an average of ~330Lm/W, and divide the chosen point of temp/bin/current LED efficacy by it, you should get a ballpark efficiency. Eg: T5 XM-L @700mA @25 C tj =128.1 Lm/W / 330 = ~38.8% efficiency.

When someone pointed this out for me, Alesh? I could see everything but that, I think he used 360Lm/W as a constant. Max efficacy is assumed to be.....

See? This is an assumption that drives LER. How do I relate that to PAR? Where does that theoretical limit on visible efficacy come from?

This is where I get confused. I read a lot of peer review, and these are what I look for. What are the assumptions?

 

[Doer]

Does sunlight conform to LER? I don't think so. Ganja plant thrive on raw sunlight. Yet we all know only mad dogs and Englishmen will go out in the noon day sun.

Our corneas cannot take raw sunlight. So, in that way LER is inferior to Ganja.

 

[SupraSPL]

Understandable LER is a confusing concept it is one of those things that will suddenly click after you chew on it and look at it from a few different angles. Here are a few examples:

A 1 watt, 100% efficient 555nm green LED would put out 683 lumens, LER = 683lm/W
A 1 watt, 100% efficient 660nm deep red LED would put out 50 lumens, LER = 50lm/W
A 1 watt, 100% efficient 2200K HPS would put out 385 lumens, LER 385lm/W
A 1 watt, 100% efficient 3000K CXA would put out 325 lumens, LER 325lm/W

So LER is taking lumens out of the equation. If you know your LER, and you know your lumens, you can switch over to % efficiency and PAR W.

 

[SupraSPL]

Yes sunlight has an LER. In space, it is about 5000K 100 CRi. So LER is about 280lm/W (my conjecture)

While you are extracting LER from an SPD curve, you will also come across another useful number, the umol/PAR W constant for that particular SPD curve. That allows us to convert from % efficiency into umol/W.

One that I am familiar with is the CXA 3000K, the figure is 4.88umol/W. So a 50% efficient CXA 3000K would create 2.44umol/ dissipation W.

 

[Doer]

Understandable LER is a confusing concept it is one of those things that will suddenly click after you chew on it and look at it from a few different angles. Here are a few examples:

A 1 watt, 100% efficient 555nm green LED would put out 683 lumens, LER = 683lm/W
A 1 watt, 100% efficient 660nm deep red LED would put out 50 lumens, LER = 50lm/W
A 1 watt, 100% efficient 2200K HPS would put out 385 lumens, LER 385lm/W
A 1 watt, 100% efficient 3000K CXA would put out 325 lumens, LER 325lm/W

So LER is taking lumens out of the equation. If you know your LER, and you know your lumens, you can switch over to PPF/PAR W.

OK, so what of that divisor 330 or 360lm/w as the max efficacy? Ultimately you do this division.

Lm/W / 330 or 360 whatever, right? Where did that divisor come from?

It takes lumen out? So, the divisor does that. And the divisor is a photometric adjustment for an energy equation. OK, I think I am seeing this now. Thanks.

 

[SupraSPL]

Right, so to get the divisor, lumens/dissipation W, we have to work our asses off LOL. That is what the charts are for. We extrapolate from the manufacturer PDF, to try and figure out how many lumens they are telling us we will get at a particular drive current and junction temperature. You can also use the Cree product characterization tool but it does not take all factors into account , such as color temp. Also the PCT does not tend to agree with the PDF curves so I stick with my charts the most part because I try to take every variable into account.

It is not perfect because there are variations in each COB, and a margin or error regarding our junction temp and temp droop. I have tried to measure actual temp droop and it appreas to be smaller than I would have expected. That indicates either a small systemic error in my method or lower junction temps than expected. But generally, we can use this method to compare one LED to another and that has been very useful.

 

[Doer]

Yes sunlight has an LER. In space, it is about 5000K 100 CRi. So LER is about 280lm/W (my conjecture)

While you are extracting LER from an SPD curve, you will also come across another useful number, the umol/PAR W constant for that particular SPD curve. That allows us to convert from % efficiency into umol/W.

One that I am familiar with is the CXA 3000K, the figure is 4.88umol/W. So a 50% efficient CXA 3000K would create 2.44umol/ dissipation W.

Yeah this makes sense, to get to count of photons per watt of work.

 

[alesh]

[blahblah]
If you take the theoretical limit for perfect visible white light efficacy as being an average of ~330Lm/W, and divide the chosen point of temp/bin/current LED efficacy by it, you should get a ballpark efficiency. Eg: T5 XM-L @700mA @25 C tj =128.1 Lm/W / 330 = ~38.8% efficiency.

When someone pointed this out for me, Alesh? I could see everything but that, I think he used 360Lm/W as a constant. Max efficacy is assumed to be.....

See? This is an assumption that drives LER. How do I relate that to PAR? Where does that theoretical limit on visible efficacy come form?
[more blah]

Mr. degree in physics, I actually took some effort, digitized the SPD curve from their spec sheet and calculated LER (~325lm/W - there's some room for error, of course, shouldn't be more than a few per cent). As a guy with a degree, you can probably imagine that LER is unique for each SPD curve. Generally it's about 315-330lm/W for standard-CRI white LEDs and about 275lm/W for high-CRI warm white LEDs.