# UV LED to replace UV fluoresces



## cwloo (Jul 19, 2010)

Dear all,

Is there any LED (Cree?) that can produce 365nm ? Need to find a LED to replace a 4 watts UV lamp used in the mosquito repellent. The ballast of the UV lamp was broken and I could not find any replacement in my local hardware store.


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## Curt R (Jul 19, 2010)

4 watts at 365 nm, try several hundred dollars worth of LEDs. :shakehead

Curt


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## bstumm (Jul 19, 2010)

LEDEngin makes a 365nm emitter with 700mW of output power and a 400nm emitter that puts out 2.2 Watts. These are the 10 Watt emitters and will cost around USD100 each. There are also some cheap chinese brand emitters but my testing of those sources are demonstrating that the specification is never correct on output power, actual radiant output is usually 30-50% of specified.


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## Ken_McE (Jul 20, 2010)

cwloo said:


> Dear all,
> 
> Is there any LED (Cree?) that can produce 365nm



http://www.thefoxgroupinc.com/index.php?option=com_content&view=article&id=74&Itemid=68



> The ballast of the UV lamp was broken and I could not find any replacement in my local hardware store.



Contact the manufacturer.


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## Oznog (Jul 21, 2010)

The "bug zappers" don't repel... they attract and kill, in theory. In practice, they don't seem to work, IIRC a study showed they zapped a wide variety of bugs but no mosquitoes.

The bug zappers usually use blacklight-white. They don't have a purple "Wood's Glass" filter to block visible light generated inside.


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## bshanahan14rulz (Jun 16, 2012)

the ledengine LED looks like it contains Cree chips, I didn't know cree made 365nm LEDs?

Also, lol @ thefoxgroupinc

edit: turns out just all the pics show the wrong LED.


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## Anders Hoveland (Feb 14, 2013)

The interesting thing about UV-LED lighting is that it could offer much higher CRI at higher CCT. 

In normal white Nd:YAG phosphor LEDs, it is just a narrow blue frequency spike stimulating the yellowish phoshor, so all the CRI is concentrated in the longer wavelength, lower color temperature, side of the spectrum. But if we look at the graph of some of the common enhanced color fluorescent lamps, we can see a wide phosphor hump in the blue-green part of the spectrum, in addition to a small spike on top of that at around 486nm.
g







I am not exactly sure what this phosphor is, but it does a great job of creating a broad hump of frequencies in the blue-green part of the spectrum. This is exactly a part of the part of the spectrum which normal white LEDs are deficient in. Now let's take a look at the graph of an enhanced spectrum LED lamp, which has a separate red frequency emitter chip:






Just imagine the CRI that would be possible if an LED lamp used three separate chips, a normal white phosphor chip, a red frequency LED, and a violet chip with that blue-green phosphor.


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## bshanahan14rulz (Feb 14, 2013)

You just bumped a year-old thread.

I bumped it when it was 2 years old. I win.

But yeah, start with a lower wavelength pump, and it opens up more possibilities for downconversion.

interesting to see the ~488nm hump, wonder if that is an argon line :-M

Have you come across any spectrographic analyses of the new Nichia 219b's that everybody's freaking out over? I've been googlign for one for a bit here and there, and couldn't find it. You are apparently much better at findign these color graphs than I am, I'm probably searching for the wrong terms.


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## Anders Hoveland (Feb 14, 2013)

bshanahan14rulz said:


> interesting to see the ~488nm hump, wonder if that is an argon line


You may likely be right about that little spike. There is argon gas inside fluorescent tubes. 

But it really does not matter. The important thing is that wide 420-670 nm hump, which must be resulting from some unknown phosphor, not the argon.
I wish I knew more about the phyiscs behind it, what types of phosphors result in broad spectrum humps. Obviously broad spectrum wide humps are much better for full spectrum coverage and high CRI.


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## cove (Feb 18, 2013)

Using 3 or 4 of Nichia's NC4U133As would be your best bet. They are more powerful than the LED Engin product but they are expensive. 
http://www.nichia.co.jp/specification/en/product/led/NC4U133A-E.pdf


FYI Nichia are due to launch deeper UV LEDs shortly:

http://www.nichia.co.jp/en/about_nichia/2012/2012_122601.html


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## Anders Hoveland (Feb 22, 2013)

a UV LED might not even be needed, a common 405nm violet chip would probably work fine with most phosphors.


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## AnAppleSnail (Feb 22, 2013)

Anders Hoveland said:


> a UV LED might not even be needed, a common 405nm violet chip would probably work fine with most phosphors.



What were the results of that being tried in industry?


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## CouldUseALight (Feb 22, 2013)

lovecpf

This thread rules..... from $3.50 replacement tube ....... to next year's 21-Volt UV proto-chip!!! 
 



AnAppleSnail said:


> What were the results of that being tried in industry?



That would be GE's Vio line, present CRIs in the low 80s and forecasted into 95+. 

Philips seems to have the best remote phosphor tech atm in the L-Prize bulbs, which use Luxeon Royal Blues even further from UV, between 440 and 460 nm. 

Am I just getting old, or are household light bulbs suddenly becoming 10,000x more interesting?!?? :twothumbs


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## Anders Hoveland (Mar 13, 2013)

AnAppleSnail said:


> What were the results of that being tried in industry?


I am not sure. I do remember reading reviews, however, that the LED "black light" (actually 405nm violet) did not work as well with glow paint. Again, I am not exactly sure how the physics work. One would think since the frequency of violet LEDs are higher than the fluorescent paint, it should not make a difference, but apparently it does. 

Some phosphors which glow under ultraviolet do not glow under 405nm. It has nothing to do with color, apparently. This amateur video gives a basic look at some of the differences:
http://www.youtube.com/watch?v=y2gbnRCIFMo

(if the guy in the video isn't a flashaholic, I don't know who is :shakehead )


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## SemiMan (Mar 15, 2013)

Is it lost on people that a 2 year old thread on a UV bug zapper light was hijacked to talk about UV excitation for white lights? .... which should have warranted a new thread. That said.

- Phosphor conversion efficiency is wavelength dependent
- There is currently no phosphor with a QE > 1, hence any the higher the pump frequency, the less losses in the phosphor
- UV leds have tended to have lifetime issues

Semiman


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