# High CRI freaks - check this out.



## blasterman (Oct 14, 2011)

When I first saw this product brief from Bridgelux I had my usual cynical skepticism you all, well, know and love me for. :wave:

Then I looked at the actual spectral graph....then I read it again....then another double take. Yeah, 97 CRI. Look at the red plot and how deep it gets. 

As for efficiency, I think Bridgelux has set a record for power hogging LEDs (the numbers are that bad), but I bet it sure looks pretty.

If jtr1962 is lurking around he's got to check the this wild spectral graph out.

http://www.bridgelux.com/products/decorarray.html


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## mvyrmnd (Oct 14, 2011)

I resent being called a freak :naughty: :banned: but that spectrum is pretty 

Now who wants to build me one into a Mag?  

EDIT: Just spotted the Vf. That just makes it more of a challenge for a modder


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## Th232 (Oct 14, 2011)

Would like the colour temp to be a little higher, but WOW! That's very impressive. I find it interesting that for the cooler option (ok, so only 2700K vs 3000K) it's got a higher output and a higher efficiency (as before, only by a bit). I can see some very nice fixed lighting or flood applications for this, pending a suitable way of powering and cooling it. A Hyperboost would work but only goes up to 1.4A, which is fine for the smaller version but not the larger one.


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## jtr1962 (Oct 14, 2011)

My main PC is down. I'll be mostly MIA for a while, until I can fix it.

Yeah, that spectral graph is wild. First thing popping out at me is why have any output at all past about 700 nm? It makes efficiency tank, but really adds nothing at all to CRI. Second thing is efficacy isn't all that bad considering-they're over 45 lm/W in warm white at 70°C with nearly perfect CRI. That's 3 to 5 times better than the incandescents this is designed to replace. If they dropped the >700 nm output, I bet they could get past 60 lm/W. And I really wish this were available in 3500K to 5000K, even if the CRI numbers were only low 90s.


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## Harold_B (Oct 14, 2011)

I suspect that there's no getting around the output above 700nM if you want deep red in the spectrum. It won't matter which phosphor type they are using in their blend to get that big red hump it will have a wide spectrum including deep red / near IR. Unfortunately that's where all the efficiency goes down is in generating the red.

Still, nice product. 97 CRI, wow. Thanks for posting the link blasterman.


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## Th232 (Oct 14, 2011)

Wouldn't it be a hoot if the spike in the +700 nm area was because of heat being radiated from the LED...


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## blasterman (Oct 14, 2011)

> And I really wish this were available in 3500K to 5000K



Yeah.....the lack of high CCT / high CRI LEDs is increasingly becoming a glaring omission rather than a curiousity. While it's a specialty market, we both know it's not THAT much of a specialty market and high CRI applications typically have a deeper wallet than residential applications. Plus, LEDs would have an even bigger efficiency advantage over tubes in the daylight / high CRI market.

Looking at the graphs the only thing thing that would need to change in order to bump from 3000k to 4500-5000k is the blue and green correct? Amber-orange-red could stay the same. Blue is easy to fix independant of other colors, but green and cyan intensity in high CRI / CCT spectra needs to lie pretty flat. Wondering if it's just not possible with current technology to get cyan-green to hit the proper ratio at high CRI / CCT so nobody tries.


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## Kinnza (Oct 14, 2011)

Very impressive color figures :thumbsup:

I decided to digitalize the SPD on the datasheet and check them. No surprises, I got almost same results for the typical spectra. Graph correspond to a R4 bin, but fall into a 3 step McAdam ellipse of 3000K (blackbody). CCT of 3040K (typical of 3045K according to datasheet). I got a slightly better CRI yet, of 98 (98,3 exactly), but as well slightly lower R9 (97,46). All figures below 1 point of CRI from the datasheet values, which can be accounted in the margin of error of working from a graph.

The R10 to R16 figures don't correspond to CRI samples, but samples of the R96 metric. With official CIE samples I got:


TCS1TCS2TCS3TCS4TCS5TCS6TCS7TCS8TCS9


98,1199,6996,0596,7898,7498,2299,5399,5597,46




TCS10TCS11TCS12TCS13TCS14


93,6286,7198,4896,8998,89


I have calculated the Color Quality Scale as well, of 96,22. Anything over 95 is excellent quality, so color rendering is almost perfect. Color appearance of the light itself would be excellent too, coordinates correspond almost to a blackbody (Duv=0,00081).

The drawback is the efficacy, obviously. For the 26W model, its 46,47lm/W (1220lm, 26.25W (700mA, 37.5V), Tcase=70ºC, Tj about 85ºC), and the 2700K version has lower lm output yet. With a luminous efficacy of Radiation of 261 lm/W(emited), it means an efficiency below 18%. At 350mA (12,42W) efficacy raises to 54,32lm/W (675lm output). But this device seems a good replacement for 35-50W halogens. Similar lm output at half the power, same color quality, 30x lifetime, reduced heat load to AA system and no IR or likely, UV.

Similar products (design and power) from Bridgelux are priced below 30$, so if they sells this one at similar price, it's cost effective, although still on the long run. But for DIYers, it could be right now a faster cost effective alternative to halogens.

Interested on the comment about the emission over 700nm, I have eliminated it on the datasheet. Result: same CRI, R9, CQS, LER enhanced to 287lm/We (that would result on 7,2lm/W more). Eliminating all over 690nm, only R9 drops (to 96), while LER raises to 296lm/We. Eliminating over 680nm, the same, CRI and CQS unaltered, R9 drops to 93, LER goes to 308lm/We, so still excellent color but that would achieve way better lm output. 

So phosphors patterns cost a lot. Two red chips (635 and 660nm peaks) would result on similar metrics of color but way better lm output if the phosphor emision were peaked way shorter but keeping emission along yellow and orage. Unfortunatelly, I dont know any phosphor that does it.

Continuing the experiment, cutting emission over 670nm drops R9 to 88 and LER goes to 322. Cutting at 660nm, CRI lowers to 97, R9 to 76 and CQS to 94, still very good figures with LER=340lm/W. Cutting up to 650nm, similar to obtained by using an standard red LED, Ra=93, R9=51, CQS=92. Not as excellent as before, but still very good color rendering (except for deep reds) and LER=361lm/W. Cutting more drops fast all color metrics.

After this analysis, I want to try the experiment of virtually add the emission of orange and/or red LEDs to a blue one using a remote phosphor, as the 4000 o 5000K of Intematix Chromalit and see what happen with color metrics. I would like to calculate the Gamut Area Index aswell, but implementation on Excel is more complicated.


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## LEDAdd1ct (Oct 14, 2011)

mvyrmnd said:


> EDIT: Just spotted the Vf. That just makes it more of a challenge for a modder



I just clicked the link but didn't see it.

What is the vF?

(and so I know, which one is capitalized, the "V" or the "F"?)


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## Th232 (Oct 14, 2011)

We're looking at the voltage, so the V is capitalised given that it's a unit named after someone (like A, F, and so on). f is lowercase (or should actually be subscripted?) since it specifies what particular voltage we're looking at, the forward voltage in this case.

It's not in the link blasterman provided to but actually in the datasheet linked from that page, 37.5 V at 700 mA for the smaller one and 24.6 V at 2100 mA for the larger one.


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## JohnR66 (Oct 14, 2011)

This is a neat product, but I agree with the others who would like to see higher color temps available. I know it is consumer mentality, but I don't see why it is necessary to keep trying to mimic the yellow light from incandescent. Even at 100 CRI, it doesn't do blue colors any favors. Most people who I persuaded to give 3500K lighting a try liked the whiter light that still had a touch of the warmth.


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## wquiles (Oct 14, 2011)

Th232 said:


> 37.5 V at 700 mA for the smaller one and 24.6 V at 2100 mA for the larger one.



That should be pretty easily handed by the TaskLED Hyperboost:
http://www.taskled.com/techhboost.html


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## blasterman (Oct 14, 2011)

I've noticed that Bridgelux tends to be cautious with their product offerings and they don't typically introduce something without an existing and established market ready to integrate it. Certainly less daring than the folks at Cree who occasionally throw something out there with the intent of _'we think this is really frikken cool, find someway to utilize it'_. Between the two companies there ain't nuthin you can't build. Really curious if Cree decides to introduce a competiting product, or if it's not worth their time. Maybe this will increase pressure for a true, 4000-5000k uber_high CRI emitter you folks are asking for.

In any respect, I'd like to be a fly on the wall at Solux corp. :huh:

I have a couple designs I'm working on this will work perfect for. Ya know, looking at the graphs I'm wondering if adding 475-480nm blue in a mixing fashion might be enough to kick the CCT up 1000k or so and keep CRI linear. Heck, add the blue/cyan on a dimmer to you can pivot color temp to taste. A Mean Well 48D will easily drive two of of these and dimming is a piece of cake on those.


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## deadrx7conv (Oct 14, 2011)

Its good to see that Bridgelux didn't forget R9-R15. 
http://www.sharpleds.com/ledevolution.html
http://megamanlighting.com/Technology/R9-Technology
http://www.lexedis.com/download/CRI_IndeXED_90_rev2_11.07_en.pdf

90CRI 4000k Sharp Zenigata's are also available in 25w and 50w. 
http://www.sharpleds.com/megazenigata.html

97CRI is great. 50lm/w is nothing to brag about but acceptable when consider the other R's. Get 95 CRI in 5000k and sign me up for a couple.


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## JohnR66 (Oct 14, 2011)

blasterman said:


> I've noticed that Bridgelux tends to be cautious with their product offerings and they don't typically introduce something without an existing and established market ready to integrate it. Certainly less daring than the folks at Cree who occasionally throw something out there with the intent of _'we think this is really frikken cool, find someway to utilize it'_. Between the two companies there ain't nuthin you can't build. Really curious if Cree decides to introduce a competiting product, or if it's not worth their time. Maybe this will increase pressure for a true, 4000-5000k uber_high CRI emitter you folks are asking for.



I see Cree is aiming right at Bridgelux with this product:
http://www.cree.com/products/xlamp_cxa2011.asp
Although there is no Cree super CRI version.
The Bridgelux high CRI array may be their first response to Cree.


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## mvyrmnd (Oct 14, 2011)

Personally I like 3000k. I think a ~2000 lumen mule-head mag mod with that hyperboost driver is smelling pretty good right now


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## Th232 (Oct 15, 2011)

wquiles said:


> That should be pretty easily handed by the TaskLED Hyperboost:
> http://www.taskled.com/techhboost.html



That's what I said previously, but really only for the smaller one if you're driving them at spec since the Hyperboost maxes out at 1.4A. If we want to drive them to their maximum ratings, the small one takes up to 1.4A (that's actually perfect for the Hyperboost), but the large one takes up to 4A!

Then again it might be a moot point for flashlight builders, with thermal constraints I can't really see anyone using these in a flashlight and powering them past 350 mA or so.

Edit: Now that I've said that I'll sit back and wait for it to happen.


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## slebans (Oct 15, 2011)

Kinnza said:


> After this analysis, I want to try the experiment of virtually add the emission of orange and/or red LEDs to a blue one using a remote phosphor, as the 4000 o 5000K of Intematix Chromalit and see what happen with color metrics. I would like to calculate the Gamut Area Index aswell, but implementation on Excel is more complicated.



I see last Thursday Intematix posted a press release discussing their new phosphor blend that combines three separate material families for a CRI of 98. Hopefully more details with be forthcoming shortly.
http://www.intematix.com/news/34/39...omplishes-Near-Perfect-Light-Quality-for-LEDs 


Stephen Lebans


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## LEDAdd1ct (Oct 15, 2011)

Thanks, Th232!


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## Kinnza (Oct 15, 2011)

Well, I did the simulation of adding virtually red to Chromalit phosphors,with promising results:


SPD of750+R0,2750+R0,12750+R0,06750+R0,3750+R0,37750+R,32+DR,12840+R,23840+R,2840+R,15840+R,08Luminous Efficacy (lm/Wi)103,1105,57107,66100,4498,8292,9896,3697,0698,3100,52CCT (K)3497,54036,84531,92993,12729,42738,22692,72807,53028,83478,1Duv-0,01589-0,00969-0,00367-0,02120-0,02369-0,02375-0,01791-0,01673-0,01430-0,00892CIExyz 1931 x0,3900,3730,3580,4090,4210,4210,4320,4260,4160,397CIExyz 1931 y0,3490,3520,3540,3460,3440,3440,3600,3610,3630,367CIEUVW 1964 u0,2430,2300,2190,2580,2680,2680,2680,2630,2550,240CIEUVW 1964 v0,3270,3260,3250,3280,3280,3280,3340,3340,3340,333LER (lm/We)305,45316,4325,93293,97287,08270,89291,5294,96301,21312,73CRI (Ra)89878186828191929589R971,5789,143,8344,433,7323,2172,3879,4494,2467,24CQS84,0681,4977,9583,883,1683,2385,3785,6985,4683,88



The title SPD means the chromalit phosphor used (750 or 840), the number after R mean the amount of power of the red LED (1W of white power, or the blue chip inside is assumed). In order to get an idea of the lm/W obtained, I've used the conversion efficacy stated on Intematix datasheet (220lm/Wrad for 750, 200lm/Wrad for 840) rounded to low, and a 50% efficient royal blue chip (Rebel and XT get it currently). Red chip with an eff of 40% (an N2 Cree, for example).

I aimed the simulation to obtain around 2700-2800K, 3000K, 3500K, 4000K and 4500K. I plan to build some lamps for home with this system, I was looking specifically to the 3500-4000K tones I prefer with good color quality. Except when going below 3000K, distance to Blackbody locus is small,in some cases very small (<4 step McAdam ellipse)

One thing I like of the results is all have Duv negative, meaning chromaticity is below planckian locus, toward purplish tones and not green-yellowish ones, as I value specially this characteristic.

AS conclusions, the 70CRI 5000K chromalit can be enhanced adding red (200mW) to 89CRI and 3500K, at 103lm/W. Excellent,IMO.

Using deep red rarely worth, and when it does, on very small amounts (about 50mW, a 20mA LED).

The CL840 can be enhanced aswell to 89CRI by adding just 80mW of red, but obtaining an smaller Duv at slighly lower efficiency that doing it with the 750 (100,5 vs 103,1). Using this system is possible easily to obtain a CRI 95 at 3000K, adding 150mW of red. And as you can see, at 2700-2800K, CRI is still over 90 at very good efficacy (97lm/W).

CQS stands for the NIST proposed Color Quality Scale.



> Get 95 CRI in 5000k and sign me up for a couple



Love the challenges! :devil:

Im going to play with it, but I need to use other phosphors. It is required >5000K? Source reference changes from blackbody radiator to D illuminant when calculating CRI at exactly 5000K, so it is different a 95CRI spectrum of 4999K to one of 5001K.


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## Harold_B (Oct 16, 2011)

Kinnza - A couple questions if you don't mind. What software are you using to run your simulations? For the Intematix phosphors in particular the Chromalit, are you digitizing the curve in the spec sheet or do you have excitation and emission spectrums?

As an aside you mentioned not being aware of an orange phosphor. Intematix makes a few silicates with an emission spectrum in the orange: O5446, O5544, O5742 and O6040.

Harold


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## jtr1962 (Oct 17, 2011)

Nice work Kinnza! The only question mark here is if you add red how much will make it through the remote phosphor? You might need to add more than your calculations show to compensate for losses. And too bad Chromalit doesn't make a 6500K panel. That would be a good starting point for high-CRI 5000K.

On another note, I'm wondering what happens when you combine the Bridgelux emitter with a blue emitter? It should certainly bring the CCT up, but the question is how far off the PL will the result be? Perhaps cyan might work better. I actually suggested to someone here who was building a light source for photography to add 640 nm red and 505 nm cyan to standard 6500K emitters. They claimed the result was excellent but I didn't really have the means to calculate exactly what my suggestions did for CRI.


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## Kinnza (Oct 17, 2011)

Harold_B said:


> For the Intematix phosphors in particular the Chromalit, are you digitizing the curve in the spec sheet or do you have excitation and emission spectrums?
> 
> Harold



I digitalized the curve on the datasheet for the Chromalit. As it correspond to emission for a royal Blue peaked at 450nm, and I used it as well, the simulation should be accurate when cold. Obviously, it might change a little at operating conditions temperature, with some shift on the peak emission of the blue LED. Response of the phosphor might change aswell, but both effects should be small enough to keep results meaningful. At the end, it is just a simulation aimed to know what to expect. I'm waiting Future carry CerFlex mixing chambers (announced for November) to order some chromalits with them, so I could make actual measurements and compare results.



Harold_B said:


> A couple questions if you don't mind. What software are you using to run your simulations?



Sofware used is own developed. It uses OpenOffice Calc sheets. One normalizes the SPD for 1W radiometric output and calculates LER. Other calculates spectral caracteristics and color metrics (data copied above was just a copy/paste of the main values calculated). And other sheet calculates the absolute SPD respect the input power and efficiency of each source. All works with 1nm waveband integration. If anybody want them, just PM and I will email them (although I need to refine them and develop 5nm waveband version).

Sheets uses CIE procedures and reference values. CCT error is below 1K (and <0,2 and mostly, <0,1K for 2600K<CCT<7500K, Duv<0,02)



Harold_B said:


> As an aside you mentioned not being aware of an orange phosphor. Intematix makes a few silicates with an emission spectrum in the orange: O5446, O5544, O5742 and O6040.



This weekend I've been playing with mixes of Intematix O5446 and EG2762 in order to obtain high CRI at higher CCTs. But in this case, simulations are less accurate, as I work with emission spectrum of both but excitation spectrum is not stated as curves, but on wide waveband ranges, so I need to assume same conversion rate along those ranges. But it is just a concept of proof, if I find interesting possibilities I will ask Intematix for more details (it is possible to customize Chromalit panels for own compositions). For the moment, I have achieved 5000K 95 CRI, but these results are more speculative.



jtr 1962 said:


> Nice work Kinnza! The only question mark here is if you add red how much will make it through the remote phosphor? You might need to add more than your calculations show to compensate for losses.



Thanks. I assumed all the red light to pass the phosphor layer. At the end, for a real example you would need to apply red power according to the efficiency of the red LED you use. But don't expect a large attenuation of red emission on the phosphor, it almost won't absorb any light of so long wavelenghts. Just some scattering, and with a <99% reflective mixing chamber, it shouldn't result on high losses at all. Anyway, when I get the samples I hope I could measure accurately such attenuation (I would need to build a larger IS with a larger port, but as I only need relative measurements for this, it is not a demanding task.

Once knowing the attenuation on real conditions, I could calculate very accurately the amount of power of a given bin of a red LED required to obtain a given CCT. But I believe above calculations should be close to real results.

I am more concerned for red shift at operating temperature, as it is way more noticeable than blue one. I have characterized well some red LED emission along a wide range of currents and temperatures so if we continue with this, I could use that data to define better the actual results. But for the moment, to minimize this effect, using the red LEDs at low current levels would be better.



jtr 1962 said:


> And too bad Chromalit doesn't make a 6500K panel. That would be a good starting point for high-CRI 5000K.



Yeah, I thought the same. As the chromalit panels are designed to result on low Duv when coupled with a royal blue, you can't lower their CCT more than 1000K without going too far from Planckian locus. In order to get a 5000K 95CRI I had to use a 6800K blue+phosphor with Duv 0,037 and add red and deep red. 



jtr 1962 said:


> On another note, I'm wondering what happens when you combine the Bridgelux emitter with a blue emitter? It should certainly bring the CCT up, but the question is how far off the PL will the result be? Perhaps cyan might work better. I actually suggested to someone here who was building a light source for photography to add 640 nm red and 505 nm cyan to standard 6500K emitters. They claimed the result was excellent but I didn't really have the means to calculate exactly what my suggestions did for CRI.



I see we think on a similar way. For the 5000K high CRI simulations I used a royal blue and a blue LED with a phosphor mix that cover the short green. I thought too on using just an orange phosphor and a cyan LED (simulation would be way less speculative) but cyan LEDs are less efficient than a royal blue pumped phosphor emitting in that range. But when just high color rendering is the goal, using a cyan LED often is a good trick.

But notice the Bridgelux Decor already covers well the range of emission of a cyan LED. The valley is peaked at 478nm, so in order to cover it, you would need to use a blue LED, of the longest peak emission avalaible (usually, about 470-475nm). Anyway, it would need a very small aid in this range, the valley is not huge enough to penalize CRI. So in this case, I think there is little to improve. But i will simulate it, (assuming a perfect light mixing, that would be another question in this case) and check the CCT change and Duv (distance to PL).

For standard 6500K, yep, cyan and red greatly improves CRI. But how good is the improvement greatly depends of the initial tint of the white emitter. I will make some simulations of this too.


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## Kinnza (Oct 17, 2011)

jtr, I checked raising the Bridgelux Decor to 3500K with Blue and cyan emitters (457,469 and 504nm peaks respectively), but on all cases it result on lower CRI, 91 (blues) or 92 (cyan). As an interesting difference between CRI and CQS, while when aplying the blues CQS lowers way less than CRI (94,5CQS), with the cyan, which gets the best CRI, CQS drops to 85,4.

It shows how important is CQS method of not penalizing increases in Chroma. Actually, it perfectly could be that the 91CRI Bridgelux enhanced with blue could render colors better than higher CRI spectrums.


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## saabluster (Oct 17, 2011)

Kinnza said:


> Thanks. I assumed all the red light to pass the phosphor layer. At the end, for a real example you would need to apply red power according to the efficiency of the red LED you use. But don't expect a large attenuation of red emission on the phosphor, it almost won't absorb any light of so long wavelenghts. Just some scattering, and with a <99% reflective mixing chamber, it shouldn't result on high losses at all. Anyway, when I get the samples I hope I could measure accurately such attenuation (I would need to build a larger IS with a larger port, but as I only need relative measurements for this, it is not a demanding task.



I'd have to run the tests again but I seem to remember getting roughly a 30% drop in lumens running a red led through the Chromalit.


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## Harold_B (Oct 18, 2011)

30% doesn't surprise me nor would I be if it were more. The phosphor layer doesn't down convert at that wavelength but that's not to say it doesn't absorb light at that wavelength. Between the phosphor layer absorption, the media layer absorption, the surface scatter / Freznel loss, and the back scatter that gets reabsorbed by the emitters, there are plenty of opportunities to lose output. That's not to say you couldn't just put in higher output reds, just that it wouldn't be as efficient as you might hope.
Kinnza - nice work on the spreadsheets. When digitizing the curves are you using software to pick up the coordinates or are you estimating them manually and entering them? I have been looking for a software to digitize spectrum curves but the freeware that I have used has fallen well short. Typically I use spectrum data gathered using an Ocean Optics spectrometer but I like to run simulations prior to having test samples on hand.


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## Kinnza (Oct 18, 2011)

30% loss :sigh:

I really hope using a reflective mixing chamber can lower it noticeably. At that level of red attenuation and current efficiency of red chips, it would be more efficient to use red phosphors instead. With the Osram announced 50% efficiency AlInGaP for next year, using the red chips would worth, but those loses does very difficult achieving high efficacy warm whites.

As far as I know polycarbonate is highly transparent along the visible and phosphor absorb very very little of long wavelengths, so the losses must come from surface scattering/Fresnell losses and backscattering, and those losses can be greatly minimized using a very high reflectivity chamber. Actually, those losses are in play too with the blue pump and phosphor coupling. Believing the conversion efficacy stated on Chromalit datasheet, the total losses except for Stokes ones is about 30-35% for the 750 tone (215-230 lm/Wrad royal blue, 336lm/Wrad final). As it includes the own phosphor losses, I do believe that at the optimal conditions Intematix measured it, with >99% reflective mixing chamber, optical losses affecting too a red chip shouldn't be any case over 15%, and probably, below 10%. That is why I'm waiting the CerFlex chambers .

Anyway, measurement of that conditions will clear it. I really hope that 30% measured by Saabluster was due high absorption so it can be minimized. If it is the phosphor itself which absorb passively the red light, there is nothing to do to improve it.

Harold- I tried too digitalizing software, but it don't work fine enough. Sometimes it is able to catch part of a graph nicely, but it is not reliable enough. So I digitalize them manually, by resizing graph in a way that horizontal pixels match with nm width, and working with large height graph so error is minimized (its not the same 1 pixel over 30, than 2 over 500). It is a time consuming task (about 1h for a 400-780nm graph), but I only do it when an spectrum interest me enough to play with it. I already have a good library of datasheet spectrums so doing it from time to time is not a problem. Usually I work too with an Ocean Optic spectroradiometer (Jaz) and mostly work with data from it.


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## saabluster (Oct 18, 2011)

OK so I reran the tests. I used a red led with a reflector around it. All measurements were in my IS. The red LED by itself gave me a reading of 288. I then placed a piece of Chromalit over it(5k version) and got a reading of 198. So my recollection was correct. The Chromalit caused a loss of 31.25% lumens. But the story is not over yet. I decided to take the substrate out of the equation to see what the loss was from the phosphor layer itself. I took a piece of Chromalit and sanded off the phosphor layer and then buffed it back to a shine. All that was left was the milky plastic they use as a support structure for the phosphor. I got a measurement of 210 with this altered piece. That means that the plastic alone is responsible for 27.083% of the loss. The phosphor layer then only causes a 5.714% loss! 

Now the question in my mind is why they use such a horribly inefficient plastic as a base.


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## jtr1962 (Oct 19, 2011)

saabluster said:


> Now the question in my mind is why they use such a horribly inefficient plastic as a base.


My guess would be for better diffusion (and Chromalit panels do in fact nicely diffuse the source LED(s)). That also explains their not so great efficiency numbers (230 lumens per watt for the 750 panel). With the best royal blue emitters (50% efficient), you end up with 115 lm/W. Using your test results, you're around 160 lm/w before diffusion losses, right about where you should be using today's most efficient royal blue emitters.


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## csshih (Oct 19, 2011)

I'll hop into this thread with a FYI:






3000K High CRI Cree, ________________6500K CW Cree.


Ocean Optics Spectrometer.


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## saabluster (Oct 19, 2011)

jtr1962 said:


> My guess would be for better diffusion (and Chromalit panels do in fact nicely diffuse the source LED(s)). That also explains their not so great efficiency numbers (230 lumens per watt for the 750 panel). With the best royal blue emitters (50% efficient), you end up with 115 lm/W. Using your test results, you're around 160 lm/w before diffusion losses, right about where you should be using today's most efficient royal blue emitters.



Yeah I figured as much too but don't think that was the right way to go. Not everybody wants or needs that diffusion. The diffusion can also be easily handled after the fact and in a manner more suitable to the manufacturer/designer. Done the right way diffusion can be much more efficient. Applying to clear pmma would boost their marketing value.


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## kaichu dento (Oct 19, 2011)

csshih said:


> I'll hop into this thread with a FYI:
> 
> 
> 
> ...


That is pretty cool - any chance you could show us an approximate representation of incan for reference?


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## csshih (Oct 19, 2011)

kaichu dento said:


> That is pretty cool - any chance you could show us an approximate representation of incan for reference?



I now wish I had (and one of the sun), but I don't have access to the spectrometer at this point.

Craig


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## kaichu dento (Oct 19, 2011)

csshih said:


> I now wish I had (and one of the sun), but I don't have access to the spectrometer at this point.
> 
> Craig


With the sun too would better yet, and if it was ever possible, the moon. 
You guys never cease to amaze with some of the stuff you come up with!


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## Harold_B (Oct 19, 2011)

No pictures to post but a quick search and...

http://www.roperld.com/science/electromagneticspectraoflightbulbs.htm

http://www1.assumption.edu/users/bniece/Spectra/HiResolution/Wg.pdf

http://physics.weber.edu/schroeder/eee/chapter6.pdf


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## Kinnza (Nov 4, 2011)

I finally added the Gamut Area Index to my spreadsheet, and I got a big surprise when I entered the Bridgelux Decor spectra in it. It only scores 58 on GAI, a very poor figure. The combined metric CRI-GAI is 78, below the 80 threshold that signal light sources with good color quality.

I know this topic may enter on the endless debate about how good is the CRI alone. Im not a big fan of CRI alone, I think it must be seen along other metrics to get a good idea of color appearance and color rendition. You can agree or disagree with that, but the fact is the Bridgelux Decor gets a very high score on CRI but a very low on GAI, and for me, that is suspicious of a light source designed specifically to get a high score on the most used metric, and not so much to provide a overall good color quality.

This is the Gamut Area plot of the Bridgelux Decor:






Compare with the plot for the Chromalit 840 plus 0,15W of red (per watt of blue):








Or the Chromalit 750 plus 0,25W of red:







They score a CRI of 95 and 88, a GAI of 85 and 100 and a combined CRI-GAI of 90 and 94, respectively. I used this examples to compare because I had them at hand, that's all, although actually I was surprised too for the high combined metric score of these mixes.


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## Kinnza (Nov 4, 2011)

It seems either picassa or the board dont allow to link more than 3 pics on a single post. I wanted to add to the SPD of the Chromalit mixes spectrum.First the 840 and last the 750:


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## mvyrmnd (Nov 4, 2011)

Kinnza said:


> It seems either picassa or the board dont allow to link more than 3 pics on a single post.



<offtopic>I've posted a dozen images at a time from picasaweb with no issues</offtopic>


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## blasterman (Nov 5, 2011)

> and I got a big surprise when I entered the Bridgelux Decor spectra in it.



Where did you obtain this 'spectra' data?


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## Kinnza (Nov 5, 2011)

blasterman said:


> Where did you obtain this 'spectra' data?



From its web page, that you linked on the first post. My digitalized SPD shows like this:






And my end results are this:


CCT (K)3039,7Duv0,00081LER (lm/Wout)262,70CRI (Ra)98,3R997,5CQS (Qa)94,8CPS (Qp)96,2GAI57,9CRI_GAI78,1MCQICIExyz 1931 x 0,435CIExyz 1931 y 0,406CIEU*V*W* 1976 u' 0,249CIEU*V*W* 1976 v' 0,522


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## blasterman (Nov 5, 2011)

> From its web page, that you linked on the first post. My digitalized SPD shows like this:



I'm still missing it. All I'm seeing is a low rez representation of a spectral curve that in no way you can make accurate extrapolations from. So unless there's some buried EXIF data in the JPEG files I'm still missing where all this data is coming from? Normally when you start with these kind of detailed conclusions -vs- other light sources you have the RAW data dumped from the spectrometer and not somebody's Excel skills. 

Not saying your conclusions are wrong....just want to know where the data is coming from other than a marketing graphic.


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## Kinnza (Nov 5, 2011)

No,man, I did not use that low res on the page itself, but the .bmp big one with high resolution extracted from the datasheet, linked on that page. This graph is a black and white one, way easier to digitize with small margin error, well below the error required to affect CRI and GAI on more that 1 point. The same reference SPD is the used by Bridgelux to calculate their CRI figures.

GAI and CRI wont go farer that 1 point from my figures.


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## tom11films (Sep 6, 2012)

Kinnza said:


> No,man, I did not use that low res on the page itself, but the .bmp big one with high resolution extracted from the datasheet, linked on that page. This graph is a black and white one, way easier to digitize with small margin error, well below the error required to affect CRI and GAI on more that 1 point. The same reference SPD is the used by Bridgelux to calculate their CRI figures.
> 
> GAI and CRI wont go farer that 1 point from my figures.



Hey Kinnza- can you tell us how you calculated CRI and CCT from that SPD curve? I'm trying to get the guys who are developing spektralworkbench to add it to their opensource spectrometer, and so far I can't figure out how to calculate from an SPD curve. 

-Tom


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## PFR84 (Dec 12, 2012)

Hi there,

I want to ask you how can we calculate CQS and GAI? I have access to spectrophotocolorimeter which can measure whole visible spectrum, CRI and correlated color temperature but nothing more. Can You solve my problem and help us all here in this topic? Thanks in advance


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## tom11films (Dec 12, 2012)

PFR84 said:


> Hi there,
> 
> I want to ask you how can we calculate CQS and GAI? I have access to spectrophotocolorimeter which can measure whole visible spectrum, CRI and correlated color temperature but nothing more. Can You solve my problem and help us all here in this topic? Thanks in advance



I have a excel spreadsheet that will calculate CQS, CCT and CRI from a spectrograph, I can share it with you if you like. I'm hoping to use the formulae in it to give CRI and CCT abilities to Public Lab's Spektral Workbench (http://spectralworkbench.org/) an opensource spectrometer for webcam, andriod and iphone.

-Tom


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## PFR84 (Dec 13, 2012)

Sending me this spreadsheet would be awesome, I'm a greenhorn here so I can't send You PM, so write down my e-mail: [email protected] and please let me know when You send this to me


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## Hoop (Dec 15, 2012)

Just have to ask: has ANYONE gotten ahold of one of the Bridgelux Decor Array emitters yet? I tried to buy one a while back but there were no distributors. I did not call Bridgelux directly.


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## PFR84 (Dec 18, 2012)

Try here:

http://bridgelux.com/media-center/events/bridgelux-and-ebv-elektronik/


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## DrJohn (Nov 28, 2013)

Hi all,
I run a photometrics lab and I've been tasked by my boss of finding a way to calculate Gamut Area Index. A google search brought me here. If Tom11 and Kinzaa are still reading this, would it be possible for me to have a copy of your spreadsheets, please?
Dr J


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