Ultraviolet Emitters

Now this looks like a scam. Right up there with the cheap SkyRay Kings on Ebay.

https://groupgets.com/campaigns/118-nvsu233a-u365-high-power-uv-led

At least their claim about unavailability through the 'regular distributors' is not true, I can buy it at leds.de for 54 euro's (~$60). I would indeed not trust the $15.50, but it is tempting....

I know a couple people with the last name Law. It’s not as common as Ho or Chan, but it seems pretty common here

You don’t want to know :frowning:
” NVSU333A, the world’s first standard, high power UV365nm, NICHIA Nichia factory direct supply “:http://translate.google.com/translate?hl=en&sl=zh-CN&u=http://detail.1688.com/offer/45343824860.html&prev=search

UV group buy starting

I have MTE-301 & Nitecore CU6, they are the best available. Nitecore marginally less visible blue spill. I’m having a torch built for me using NVSU333A which should be interesting, will post a review when done on my UV page.

Btw if you want to test the purity a UV torch, don’t use paper (it is dyed to fluoresce), shine it on a spoon, that’ll show you the visible blue spill. The spoon should be black (no reflected visible light at all). If it’s blue you have visible blue being reflected from the torch.

-Johan

You don’t want to know :frowning:
” NVSU333A, the world’s first standard, high power UV365nm, NICHIA Nichia factory direct supply “:http://translate.google.com/translate?hl=en&sl=zh-CN&u=http://detail.1688.com/offer/45343824860.html&prev=search
[/quote]

Wow, like 158 USD each lol. If you order 5 or more it’s 153! XD

Wow, like 158 USD each lol. If you order 5 or more it’s 153! XD
[/quote]

So $5 off if you order 5 or more, you say?

New group buy! NVSU333A, we need 150+ people to get them at $3/unit, and they’ll throw in a custom copper DTP star! :stuck_out_tongue:

I realize this is a bit of an old thread, but I had a customer send me a NVSU333A U365 to be installed in one of my copper p60 modules. IIRC it fits the xhp70 sinkpad fine (this was a while back). Just like a cree you can over drive them. I think I ran it with a mostfet driver at like 6-8 amps. This particular customer had a high risk tolerance ($150ish LED). The emitter held up. This is also how I discovered that older Surefire 6P bezels came with a polycarb lens and not a glass one. I stuck it in my 6p and ran it a few seconds to find out if it was working and this was the result.

Aside from that hiccup everything went perfectly. Despite the “safe” UVA wavelength I’m gonna have to say watch your eyes/skin boys.

:open_mouth:

Thanks for the report, that 333A seems awesome, time for a lowered price for them, like Nichia did for the 276A.
UVA is very nasty for your retina btw, polycarb glasses obliged!!

What is your opinion on the basic low power 395nm UV LED flashlights commonly being sold? I typical opt for wearing glasses when using any UV stuff, but it seems to be a common belief on the internet that its basically “safe”? I’ve not been able to find much solid data.

The 395nm flashlights are not safe. Our eyes are just very slightly sensitive to 395nm, so if we see a faint purple glow, our eyes already receive lots and lots of light, and our pupils do not contract in response of that like they do with white light.

The danger gets greater when the intensity increases and when the wavelengths gets shorter: our eyes respond properly on green light; our pupils contract and we look away when there’s lots of it, a flashlight with a blue XP-E2 at 1.5A will already be harmful if used for a while; our retina’s receive quite a lot of radiation without much noticing it, a properly driven 395nm flashlight can do proper damage when used for a while without eye protection (yellow glasses), a 365nm flashlight can damage your eyes in a short period of time.

Personally I notice when my eyes receive much UV, my retina’s start hurting. Probably then already some damage is already done but I get the impression that it fully recovers. I will not test what happens if I at that point continue without protective glasses.

I’m with you. I had never thought about the pupils not contacting to the wavelength of light. I have had that experience of my eyes hurting. I was pointing a uv light away from me in an open area ( I didn’t own the correct glasses back then). Within a few seconds I could feel a difference in my eyes. Working on the lights I always thought it a good plan because of the risk of getting a direct hit from the beam, but you bring up a good point for any use. Thanks again.

Am I correct in assuming that the ratings on these are two different things? The cheap one being 3 watt as in its rated power consumption. The nichia 540mw meaning some form of output of the beam similar to a lumen rating? If so is there a way to estimate the output of the cheap one?

Can standard glass be used across all wavelengths of UV. Example polycarb is ok for 395, but will block 365mn. Is glass ok for those, and for wavelengths below like 280 etc?

-yes, the cheap one lists power consumption, the Nichia ‘radiometric output’, you can not use the lumen because the lumen measures visibility by the human eye and 365nm is completely invisible, it would be always zero lumen. Output of the 3W led could be 500mW though if it is any decent. 500mW is very ok for a 365nm led, although the latest ones emit 1000 mW, some even more. The cheap ones that I have seen thusfar emit apart from the UV quite some visible light that may obscure the fluorescence light that you want to see when using the UV (the visible light from the led may be blocked by using a UV-pass filter in front of the led, like a ZWB2 or UG1 filter). Nichia 365nm leds are known for emitting very little visible light aside from the UV.

-measuring UV is not straightforward unless you buy a special device for it. I myself have devised a makeshift method by measuring copier paper fluorescence in a standardised way, but I do not claim a great accuracy.

-from around 300nm and up standard glass will transmit close to 100%, but the 280nm deep UV leds need quartz glass (other name: fused silicon), indeed polycarbonate has a cut-off around 400nm, PMMA is a little lower, it transmits most of the 365nm radiation.

Thanks dj. Just to confirm. Is this, this is the mcpcb I would need

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For this emitter right?
http://www.leds.de/en/High-Power-LEDs/Nichia-High-Power-LEDs/Nichia-SMD-LED-UV-NVSU233A-without-PCB-emitter-395nm.html

those UV LEDs are very sensitive for overheating and have a way lower thermal damage temperature than white or blue LEDs

you want a DTP star or at least a copper star with a thick layer of copper to spread the heat
if you use a DTP star you can heatsink the cathode way better, but you have to insulate most hosts from the PCB with a Kapton tape or similar stuff

For some reason even though I am using 395nm (from a reliable source) I managed to wreck some LEDs and optics today.

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I’ve been using plastic fresnel lenses with these and had no problem so I sort of assumed this would work too, but I guess not LOL :slight_smile:

I wonder how a LEDLIL cute-3 would react to hi power 365nm? Its made of PMMA (Acrylic) vs. Carclo's Polycarbonate (PC).

Silicon seems to be the standard material for UV optics. There is a link to this page from Nichia's UV page.