Luxeon Lime for tunable white light with a high CRI

R_Mc

New member
Mission Statement: Design a high CRI LED for a macro algae tank capable of simulating solar radiance over the course of a day.

Additional Requirements:
  • CRI and R9 must be above 90 throughout the temperature range
  • Color value should remain just south of the black body curve for better reds
  • CCT minimum range must be 2700 to 4600
  • CCT prefered range would be 1900 to 5600
  • output must be at least 1000 lumens throughout the range
  • 2 channel control is prefered for simplicity
  • UV extension to 400nm and IR extension to 700nm is prefered - no extension needed beyond this
  • Minimal emitter count is preferred (Warm white + Lime / ww + cw)
  • Small footprint is essential


General thoughts and questions for the community:

Cool white + Warm white combo chips - Initially I was considering using combination COB boards like these
1392743094055.jpg
or
140218-Sharp-Tiger-Zengata.jpg
or a cree 30-50W combo board with a string of ww/cw.

The problem is that the cool white is almost always a poor performing...same as always...terrible green yellow gross cool white. This can be partially avoided by creating a multiboard using Nichia 4500k 90+CRI and a nice 2700k but all 2700's I've found are too yellow without enough red.

Prebuilt tunable LED's - I haven't been able to find many of these but there exist prebuilt cobs that can be tuned from low to high temperatures
TA_LED_F_STARK_SLE_PREMIUM_without_housing_small.jpg
Lighten_Releases_a_New_Generation_of_High_Power_Multi-Color_CoB-LED_Solutions_-_LED_Times.jpg


The benefit is that a high CRI can be maintained throughout the color temperature range. The down side is that it would require a complex control / power configuration resulting in a much larger end package than I'm looking for.

Similarly RGBW leds offer the ability to tune one chip to a color temperature with a high "cri" but the color would still leave gaps and the resulting spectrum would be peaky.

The_M63_RGBW_-_SemiLEDs_-_LED_Times.jpg


What I'd really like to find is a RGBW chip that uses PC blue Cyan for the blue, PC amber, and PC lime in addition to a high cri full spectrum warm white (2700-3000k)

it seems that this exists - http://www.digikey.com/en/articles/...e-green-leds-encourage-color-tunable-lighting However, I have not been able to find a prefabbed part.

Best option may be to configure a 4-6 up board here http://www.luxeonstar.com/Rebel-Quad-LED-Assemblies_c_4723.html

Very interested in any thoughts / opinions on this design
 
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R_Mc

New member
from luxeonstar it would be $23 pre shipping for a 4 up board

POS 1: 2700K ANSI White - 135 lm (LXW9-PW27) - US $3.90
POS 2: Lime - 313 lm (LXML-PX02-0000) - US $5.80
POS 3: 2700K ANSI White - 135 lm (LXW9-PW27) - US $3.90
POS 4: Cyan - 122 lm (LXML-PE01-0070) - US $5.08
Base: Mounting Base (SP-08A)
 

Fredfish

New member
FWIW, CRI is only useful in telling us how well colours will be rendered under a given light. It says nothing about how well anything grows under it.

As far as I know, the greenhouse industry still uses HPS bulbs (ugly crap yellow green colour) to boost growth.

I think the jury is still out on LEDs for greenhouse use. There is a lot of (very secrative) work going on by larg research entities on commercial production using LEDs, but nobody has hollered "Eurika, I've got it!" yet.
 

R_Mc

New member
I should have stated - the main goal is an aesthetically appealing light. Not necessarily a high par solution.
 

Fredfish

New member
I should have stated - the main goal is an aesthetically appealing light. Not necessarily a high par solution.
Sorry, I read it the other way around. Is this for a display fuge?

I remember someone on another site playing around with spectrum summing using a spreadsheet. The combination he came up with that was closest to sunlight was royal blue, blue, cyan lime and 27K warm white.
 

R_Mc

New member
Hi oreo - I was considering those but I'm not so sure I trust them. They only seem to be available through the manufacturer and only in quantities of 100+.
 

mcgyvr

New member

oreo57

Active member
Hi oreo - I was considering those but I'm not so sure I trust them. They only seem to be available through the manufacturer and only in quantities of 100+.

There package products and probably LED actual production is probably not them.. but I see no red flags.
http://www.beijingyuji.com/EN-About-Us/index.html#

But it is the internet.
My problem is they are not selling the bulbs they used to and of course I have no use for 100 5630's.. more like a dozen for trials maybe.. ;)
 

R_Mc

New member
Specifically 1:45

I agree that aesthetics are personal but there is general preference for particular qualities in a light. Most people prefer a light source slightly below the black body curve for example.

I think I am settled on the luxeon z package and would like to find a tightly packed prefabbed multichip where the colors can be customized and a minimum of 2 independent strings exist. They show such chips in the demo reel but I haven't been able to find them anywhere.
 

R_Mc

New member
There package products and probably LED actual production is probably not them.. but I see no red flags.
http://www.beijingyuji.com/EN-About-Us/index.html#

But it is the internet.
My problem is they are not selling the bulbs they used to and of course I have no use for 100 5630's.. more like a dozen for trials maybe.. ;)

In speaking with them they are re-engineering a lot of their bulb line for higher lumen output. Efficiency was too low for most people. If you email them directly they may be able to sell you some.
 

mcgyvr

New member
Specifically 1:45

I agree that aesthetics are personal but there is general preference for particular qualities in a light. Most people prefer a light source slightly below the black body curve for example.

I think I am settled on the luxeon z package and would like to find a tightly packed prefabbed multichip where the colors can be customized and a minimum of 2 independent strings exist. They show such chips in the demo reel but I haven't been able to find them anywhere.

I'd call Future Lighting if anything.. (well I'd just call Phillips and ask first)
I'd guess they may be available to "OEM"s for free as demo/development kit but I don't see them sold anywhere.

Just make your own man.. This is the DIY section..:idea: There are a few vendors on ebay offering custom metal clad PCB's to your gerber designs.. (Sitopway on ebay as them cheap)
 

R_Mc

New member
That's fair... These chips are tiny though...and I have no smd reflow experience. Any tips? Will these companies provide pre tinned boards or stencils?

I have a gas oven or a cast iron pan if that counts towards reflow equipment ;)
 
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mcgyvr

New member
Its "easy".. I've used a hotplate and an old toaster oven works too..
don't really need a stencil (but they do those too).. For low part count like this just get solder paste in a syringe.

You can even do them one at a time (or a few at a time) with a hot air gun ($70 bucks or so from China). I did 10 proto boards with 30+ parts (most 0402 resistors and a few IC's) with a hot air gun only.. Took a while but came out perfect.
It really is easy to do.. IMO..
Small blob of solder paste (very small dot) on each pad.. stick part to it, heat and done.
 
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