# Looking to buy Phosphorus, to make Blue LED's white



## mds82 (May 4, 2011)

I know that White LED's are Blue Die's with a phosphorus coating. What i am looking to do is something custom and i am looking for the phosphorus needed to make the blue light white. 

I know that with the Philips 60w equivalent bulb, they are using Blue LED's and then the outside yellow part converts it to white light. I know its the whole idea behind the remote phosphorus and I'l looking to do something similar







does anyone have any suggestions on what type of phosphorus to use / where to get it, etc ?

Thanks in advance for the help


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## HarryN (May 4, 2011)

Intematix


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## Harold_B (May 4, 2011)

How many of what are you looking to make? There are several manufacturers of inorganic phosphors like those typically used in LEDs and in the remote phosphor bulbs like the Philips you show. There are also organic phosphors (dyes) that are mostly used for lasers and solar applications but are being used in LED neon bulb replacements. Most of the inorganic phosphor manufacturers will have spectral data available for the individual phosphors but not for blends. You are on your own there (it's a patent mine field). In other words, what color do want and if you want white how important is CRI?

A few grams of phosphor can run a couple hundred dollars. Do a Google search for phosphors for SSL or LED and you'll find several manufacturers.


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## mds82 (May 4, 2011)

Well i'm not looking to make many, but I'm trying to make a ring that's about 4 inches in diameter and is only about 1/4inch thick or so. Its just an idea at this point but i was almost thinking if there was a paint that i could use that would probably be the best. For color i do not want a warm color, ideally like a 8000-9000k color.


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## Harold_B (May 4, 2011)

You have a few challenges to overcome there. I'm not aware of any paints that have phosphor suspended in them that fluoresce at anything other than UV (black light or glow in the dark paints) and they are not typically translucent or very efficient. Do you already have the blue LEDs? If so then that will point you in a direction as well. HarryN mentioned Intematix and they are just as good a place to start as any. You can find their entire catalog online. I would find a cheap YAG, mix it with some silicone and smear it between a couple of sheets of PMMA. If you are planning to sell these you will want to research the patents because there are a lot of them and the owners play nasty.

As far getting the color temperature you want that will come down to trial and error. That is accomplished by adjusting the amount of phosphor you use within the volume of the gap you are filling. Basically you are balancing the blue and yellow spectrum peaks to get the average color temperature you want.


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## HarryN (May 4, 2011)

Hi, just so you know, you can buy Lumileds Rebels in something like 18 part numbers just in "white". These vary across the CCT and CRI range, so it is an easy as picking your spectrum off the shelf. If you want a bit more blue, you can just add a few blue LEDs. 

You can also blend monochromatic LEDs (not just RGB, but a bunch of them) to come pretty close to most needs.

Usually, this is easier than blending phos to make your own color mixture, but it is ultimately up to you. I know for my projects, sometimes cost has nothing to do with the project - that is why it is called a hobby.


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## saabluster (May 4, 2011)

I figured out how to "harvest" the phosphor off of LEDs and transplant them but it probably won't help you if you are trying to cover that much area. I have seen some yag for sale through Chinese channels but have never pursued them because I already have enough irons in the fire.


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## Oznog (May 5, 2011)

You might be able to harvest the phosphor off a fluorescent light. IIRC, the gas startes from a UV-A wavelength instead of blue, but blue might still energize it.


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## billw (May 5, 2011)

1) It's "Phosphor", not "phosphorus." The latter is a rather nasty elemental chemical, prone to self-igniting near room temperature, highly poisonous, and prone to attracting the attention of the DEA (used in Meth synthesis.)
2) You can start with most fluorescent paints or dyes. Many of these will fluoresce under blue LED lighting as well as UV. "Yellow" is not a particularly common color, and I'm pretty sure the phosphors on LEDs are a lot more efficient than you'll find in most paints, but it's a starting point. A lot of the "exotic color" LED toys you see around (pink, for instance) are blue LEDs with a touch of common fluorescent paint.


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