# high CRI, high output violet based LED



## jeffkrol (Jun 5, 2013)

One of the great failings of LED's (esp "just" white) is the design flaw of being based on a blue LED and phosphors. Top it off w/ engineers refusing to push the phosphor limits to include certain spectrum components (notably cyan/violet/deep red) means LED's have a "look" short of their potential..and became a "good enough" product.
Well times are changing hopefully..
For the curious, I've mentioned Yuji and their violet pump based emitters before. Unfortunately the true violets were relegated (currently) to low output .5W emitters.
Their line of high CRI blue based do, at least, cover th deep red/cyan flaws but of course not the violet. 
well found today (not exactly new) another "brand" (but AFAICT no "bare" chips) of lighting products for the more DIY inclined but not from scratch crowd.
Soraa..
Oddly enough the only "weakness" (and it is not very weak) is in Royal or deep blue..
Anyways here is a pr sheet:








A bit expensive and current variety is limited though:
https://www.earthled.com/collection...5watt-equal-95-cri-sr111-18?variant=896172761

For plants/people/ and fish it is worth considering...

Another source, link to 5000k (highest):
https://www.energyavenue.com/Soraa/5000K


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## AWolf (Jun 13, 2014)

I wonder how the beam angle of 120 degrees is achieved on the LED's. Is it done with reflection or refraction? Working with the bulb, spot and cheaper Marine Land Hidden strips LED's that have very little beam angle has proven difficult because of burned leaves and strong algae growth. I am trying wax paper and angular glass to spread and lessen the intensity. I don't want to raise them so high off of the tank that it spills light all around the room. Using just cut/angular glass covering the lenses did not work for me, and I had to add four layers of wax paper. Amazingly the lights are still bright. I'm hoping they will grow plants this way until the industry catches up to planted tank needs with reasonable pricing, circuit boards that don't quit within a year, and that 120 angle. 

I had great success with CFL's. Not so much with LED's yet, but I won't give up.


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## jeffkrol (Jun 5, 2013)

AWolf said:


> I wonder how the beam angle of 120 degrees is achieved on the LED's. Is it done with reflection or refraction?


small silicon or "plastic" lens .. Remember that "natively" the greatest angle one can have is 180-ish..


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## GrampsGrunge (Jun 18, 2012)

A lot of their lamps are too narrow a beam dispersion of planted tank use.

Spots instead of floods. Also noted they don't have great watt to lumen output, I suppose this will improve with time.


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## jeffkrol (Jun 5, 2013)

GrampsGrunge said:


> A lot of their lamps are too narrow a beam dispersion of planted tank use.
> 
> Spots instead of floods. Also noted they don't have great watt to lumen output, I suppose this will improve with time.


Yea the 60 degree aren't too bad..Fairly low K as well but.. point is it is a start..

Tried to get some loose chips but no luck..
Yuji's 5730's are OK if one wants to do a smd array. Need lots of chips w/ a not so cheap price. Though to be honest not really more than "retail" name brand emitters..well maybe 2x at $1/.5W so $6 for 3w..
VTC Series High CRI SMD LED - VTC5730 - 100 pcs ? High CRI LED Webstore
Just a bit hard to deal w/ on a DIY level..


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## GrampsGrunge (Jun 18, 2012)

I've got an old Compac laptop power supply/charger, 6 amps at 18 volts. It would be nice to have available an LED chip that could be run in series of it without needing an extra regulator circuit. It could drive a lot of lumens.


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## jeffkrol (Jun 5, 2013)

GrampsGrunge said:


> I've got an old Compac laptop power supply/charger, 6 amps at 18 volts. It would be nice to have available an LED chip that could be run in series of it without needing an extra regulator circuit. It could drive a lot of lumens.


Yea 5 in series and 50 strings in parallel..125W.. 
Constant voltage w/ resistors..(4.7Ohm 1/4W on the end of every 5 leds)
105W of LED output..
$237... 
to do constant current you can get "LED display" drivers..
http://cds.linear.com/docs/en/datasheet/3599ff.pdf


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## Arun. (Apr 30, 2016)

jeffkrol said:


> Yea 5 in series and 50 strings in parallel..125W..
> Constant voltage w/ resistors..(4.7Ohm 1/4W on the end of every 5 leds)
> 105W of LED output..
> $237...
> ...


but.... 120 mA ?.. or I didn't understand something ?


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## jeffkrol (Jun 5, 2013)

120mA @ 3v = .36w each


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## JasterMake (Mar 21, 2013)

Maybe I could just replace the leds on the beamswork. $95(leds)+$45(beamswork)and have a great CRI.


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## ichy (Apr 6, 2015)

Getting closer! I have "paused" my search for the holy grail of LED's. There are lots of "close" options but nothing really hits the mark right now.
If I had to build a light right now I think I would get a beamswork housing and tuck these into it and be done.

VTC Series High CRI MCPCB LED Module - Unit: 5 pcs ? High CRI LED Webstore


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## jeffkrol (Jun 5, 2013)

You could possibly for the .5W ones, depending on the diode "footprint"..


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## ichy (Apr 6, 2015)

I know not the same as aquatic plants but here is the Yuji BC "cheap" $45 COB series LED growing orchids. These are in completely dark Mn basement all winter. This orchid starting blooming about a week ago. The COB is turned down to about 1/3 max brightness.


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## jeffkrol (Jun 5, 2013)

High CRI blue base emitters are still a step above the "normal" whites..
Still... knowing the high CRI high watt violets are out there and not really available to "normal" people in a DIY form is quite annoying.
Sorra won't sell loose chips and no word from a Korean supplier. of like product. Not holding my breath of course.. 
Luxeon makes "crisp white" COB's but at best a high of 4000k (may be specialty purchase) but mostly 3000k and "only" 90CRI
http://www.lumileds.com/uploads/482/DS138-pdf
got a Yuji design in the works if I decide to dump the $100 on sub-watt chips..
But it will be a hybrid of high CRI ww and High CRI violet cw design..
Don't want to learn Eagle for this though..
Anyone want to volunteer building an eagle (or related) file to spec???

Related:
Need to check this out a bit.........
http://www.unistars.com.tw/en/index.php
http://www.unistars.com.tw/en/uploa... High CRI LED Emitter Specifications_SV-4.pdf










South Korean company:
https://www.google.com/url?sa=t&rct...sSK2R3zTQ&sig2=H6RXOzOcodn__nSggOQipQ&cad=rja
http://www.high-cri-led.com/ramax-technology/about-ramax.php


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## O2surplus (Jan 31, 2010)

Jeffkrol- 
Those unistar LEDs use the same solder pad dimensions as the cree xp-g2. Check fleabay or cutter electronics for a pre-made bare PcB designed for the cree and solder in the unistar LEDs in their place. Easy as pie.


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## jeffkrol (Jun 5, 2013)

No, more complicated than that.. Need a board for 8x3 series 5730's made by Yuji. W/ a Luminous Devices center cut out..
https://cdn.shopify.com/s/files/1/0....0.0_YJ-VTC-5730-G01.pdf?17092324451392195409
2.5x2.5 w/ mounting holes and connector..


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## O2surplus (Jan 31, 2010)

Ahh.. now I get it? Gimme a few more details and I might be able to help you out. You want 8 channels with 3 yuji LEDs in series, a COB array smack dab in the middle, all on a 2.5" x 2.5" square? Sounds easy enough...


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## jeffkrol (Jun 5, 2013)

O2surplus said:


> Ahh.. now I get it? Gimme a few more details and I might be able to help you out. You want 8 channels with 3 yuji LEDs in series, a COB array smack dab in the middle, all on a 2.5" x 2.5" square? Sounds easy enough...


4 to 2 channels.. The 8x3 series diodes just need to be bridgeable one driver from 3
The last channel is the COB..
so really 2 channels but the option of 4.
3.6 x 8 = 28.8 driven at 120mA
120mA x 3 = 360mA 
LDD-h350.. 
Unless I eventually just divide up the series parallel string of Yuji emitters..
Haven't decided yet.. but not likely . 

Something like this:









There is a 1"x1" hole in the circuit board so the Luminous COB will direct mount to the heat sink..But want the +/- to be attached to the circuit board. Not really necessary though..
SMD5730's flipped every other one so as to easily trace from one to another..PIA for placement though..


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## easternlethal (Feb 13, 2016)

Why do you need so many diodes?


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## ichy (Apr 6, 2015)

I had a design idea similar to that. Mount a COB in the middle of a heatsink, then I was going to mount a strip on each of the 4 sides on separate channels.

My morning coffee read was the unistar datasheet.

Those unistars have lot a going for them....They should run nice and cool with a <4 thermal resistance as well!
I wonder how moisture sensitive they are?


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## ichy (Apr 6, 2015)

Reading a spec sheet on the one COB...it says it has "mouse bites".
What are mouse bites?


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## jeffkrol (Jun 5, 2013)

easternlethal said:


> Why do you need so many diodes?


The center COB max output is 37.5W aprox but will be driven at 1/2 or less..
The 8x3 diodes are actually higher than .5W each but driven at about 117mA at 3.7V max soo........ .431W each x 24 =10.3W

Point is to keep the whole unit in a range of 10-30W...............
I'll have 4 "pucks" over a 55gal...........


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## jeffkrol (Jun 5, 2013)

ichy said:


> My morning coffee read was the unistar datasheet.
> 
> Those unistars have lot a going for them....They should run nice and cool with a <4 thermal resistance as well!
> I wonder how moisture sensitive they are?


Not even sure if they are obtainable...except in large lot OEM type buy.



ichy said:


> Reading a spec sheet on the one COB...it says it has "mouse bites".
> What are mouse bites?


Could just be the screw cut outs..????


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## Nordic (Nov 11, 2003)

What is your budget? It is pretty cheap these days to have PCB made from online vendors.
I could slap some cam files together for you that you can have manufactured.
Haven't done it in a while but can do with a distraction.


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## ichy (Apr 6, 2015)

jeffkrol said:


> Not even sure if they are obtainable...except in large lot OEM type buy.
> 
> 
> 
> Could just be the screw cut outs..????


Maybe just maybe, with these higher CRI leds the aquarium lighting industry will latch onto them and advance aquarium LED lighting to the next level???? I know we are talking DIY here but it can't hurt to advance the lightning trade in general.

Bump:


Nordic said:


> What is your budget? It is pretty cheap these days to have PCB made from online vendors.
> I could slap some cam files together for you that you can have manufactured.
> Haven't done it in a while but can do with a distraction.


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## jeffkrol (Jun 5, 2013)

ichy said:


> Maybe just maybe, with these higher CRI leds the aquarium lighting industry will latch onto them and advance aquarium LED lighting to the next level???? I know we are talking DIY here but it can't hurt to advance the lightning trade in general.
> 
> Bump:
> 
> ...


I wouldn't mind that one bit.. Just a bit O/t re: Yuji..
From my old haunt dpreview :
Re: Yuji High CRI Bulbs tested: Studio and Lighting Technique Forum: Digital Photography Review


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## ichy (Apr 6, 2015)

Have you seen Fritzing?
http://fritzing.org/home/

I've only played with it a bit, but might be an easy solution to PCB.


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## jeffkrol (Jun 5, 2013)

Nordic said:


> What is your budget? It is pretty cheap these days to have PCB made from online vendors.
> I could slap some cam files together for you that you can have manufactured.
> Haven't done it in a while but can do with a distraction.


Boards are in budget.. It is just getting it designed.. Never liked learning foreign languages and Eagle is a foreign to me as Canonese..  
not even sure the yuji footprint for the LEd chip is "standard' or not..
or where to find the profile in its library..


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## Nordic (Nov 11, 2003)

Hehe, you can draw your own parts in eagle. It is the first thing I would teach someone on it, the layout and design bit comes with practice. Busy downloading eagle, as I said, haven't used it in a while, put I'm quite proficient.

With each of those LEDs pulling 400mW you will need quite the heatsink I suspect to slap them all that close.
Haven't really looked at the graphs yet. Will need much more coffee first.

Luminous devices cut out?


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## jeffkrol (Jun 5, 2013)

Nordic said:


> Hehe, you can draw your own parts in eagle. It is the first thing I would teach someone on it, the layout and design bit comes with practice. Busy downloading eagle, as I said, haven't used it in a while, put I'm quite proficient.
> 
> With each of those LEDs pulling 400mW you will need quite the heatsink I suspect to slap them all that close.
> Haven't really looked at the graphs yet. Will need much more coffee first.
> ...


Luminous Devices is an LED COB brand..
Had planned on instead of mounting it to the board which is then mounted to the heat sink.. just cut the circuit board out so it can be directly mounted to the heat sink..
Not sure any board people will do a knock out (or the cost.. but should be simple enough to do after they are made (boards not. w/ chips)

you can see the copper heatsinks w/ just the COB's..There are just 3 here. Heatsinks are designed to passively cool about 40W dual core CPU......


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## Nordic (Nov 11, 2003)

I've done reflow soldering with now more than a run of the mill heat gun and a syringe of reflow solder.

With a copper heatsink I would use https://www.amazon.com/Coollaboratory-Liquid-Thermal-Interface-Material/dp/B0039RY3MM. The stuff will melt away aluminium in no time though.


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## easternlethal (Feb 13, 2016)

jeffkrol said:


> The center COB max output is 37.5W aprox but will be driven at 1/2 or less..
> The 8x3 diodes are actually higher than .5W each but driven at about 117mA at 3.7V max soo........ .431W each x 24 =10.3W
> 
> Point is to keep the whole unit in a range of 10-30W...............
> I'll have 4 "pucks" over a 55gal...........


Won't that look too colorful?


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## jeffkrol (Jun 5, 2013)

Nordic said:


> I've done reflow soldering with now more than a run of the mill heat gun and a syringe of reflow solder.
> 
> With a copper heatsink I would use https://www.amazon.com/Coollaboratory-Liquid-Thermal-Interface-Material/dp/B0039RY3MM. The stuff will melt away aluminium in no time though.


looks like scary stuff... 



easternlethal said:


> Won't that look too colorful?


3000k +5600k at equal power averages 4300k a nice neutral white..


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## ichy (Apr 6, 2015)

I can CNC a center out for you if you get this going.


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## easternlethal (Feb 13, 2016)

jeffkrol said:


> 3000k +5600k at equal power averages 4300k a nice neutral white..


I see. what made you decide on mixing whites to make 4300k? I would have thought it's be better to run 5600k at full and just supplement with cyans and violets


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## jeffkrol (Jun 5, 2013)

easternlethal said:


> I see. what made you decide on mixing whites to make 4300k? I would have thought it's be better to run 5600k at full and just supplement with cyans and violets


Well except for the violets.. multi-colored LEd's were what I built with..
Mostly because 1) cyan was in short supply 2)deep red was in short supply. 3)violet too but never "warmed" to any violet toning nor expense really.

Even w/ these multi-colors I always ran a mix of ww/cw in general..
Problems were compounded w/ cheap low CRI whites of both warm and cool varieties..
ww were "tannin stained" yellow and cw too blue even ,mixed it was hard to get to the "just right" look w/out adding colors such as cyan and deep red..even royal blue.

Lately I've just been impressed w/ the high CRI whites, esp those w/ the violet pump base..
the adding violet in a more "stealth" package than as a separate diode..

also liking some sort of "sunrise effect" means you can't really use one color white..
Using say red and ww will lead to poor crisp noons. Using cool white and red gives you an odd "pink based" sunrise instead of orangy/yellow..

for a few years I held to the 5 channel design.. ww/cw/r(all types of red)/g(all types of green inc. cyan)/b as the most versitile and really enjoying.. still do in a sense but want to try something a bit different w/ the violet pump emitters and COB's.
It really isn't matter of better but different.
Still need a healthy amount of cyan/deep red to make a "complete" spectrum..


Still easier to slap rows of 3W diodes on a slab of aluminum then going through all this..

 

These are too expensive and really not powerful enough (arguable point) for prime time by themselves and one can't K shift in the beginning and end:
5600k purple pump yuji diode, note high cyan/red/deep red component.









Basically a violet w/ a rgb phosphor, not unlike current t5's ect except no mercury or UV ..
At first I was worried about the stability of the pump but been informed (not by Yuji) it is the stability of the blue phosphor that may be more of a "stopping point" for violet based emitters..


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## jeffkrol (Jun 5, 2013)

Fixed the trace path on the prev. image. not sure what the heck I was thinking..
Reduced the diode count to 7x3 mostly to have spares..


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## GrampsGrunge (Jun 18, 2012)

jeffkrol said:


> Luminous Devices is an LED COB brand..
> Had planned on instead of mounting it to the board which is then mounted to the heat sink.. just cut the circuit board out so it can be directly mounted to the heat sink..
> Not sure any board people will do a knock out (or the cost.. but should be simple enough to do after they are made (boards not. w/ chips)
> 
> you can see the copper heatsinks w/ just the COB's..There are just 3 here. Heatsinks are designed to passively cool about 40W dual core CPU......


I acquired a bunch of Thermaltake AMD Socket A type heatsinks from some retired PCs at our local community college recycling program. 

I'm hoping the 5600K Cob Yuji's come down in price, because I'd really like to try building some of the 12~18 volt Cobs onto those heatsinks I've got saved.


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## jeffkrol (Jun 5, 2013)

ichy said:


> Reading a spec sheet on the one COB...it says it has "mouse bites".
> What are mouse bites?


Found this:
https://learn.sparkfun.com/tutorials/pcb-basics



> *Mouse bites* - an alternative to v-score for separating boards from panels. A number of drill hits are clustered close together, creating a weak spot where the board can be broken easily after the fact. See the SparkFun Protosnap boards for a good example.


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