# 350nm UV LED



## Joshua (Sep 16, 2002)

Hi guys,
I am fixing to purchase the 350nm UV LED from Rothner Lasertech and wanted to know if anyone here has ever bought one of these before. There expensive though (I think it's $30 per LED)




At this wavelenth they should not produce hardly any light at all right? I thought a TRUE UV LED was about 362nm. This seems below it. If anyone has any info on this type of wavelength LED or just wants to comment please post. 
----Joshua----


----------



## sunspot (Sep 16, 2002)

There are different levels of UV. UVA, UVB and UVC. 350nm is getting into the danger zone. Harmful to all living organisms.
Check this out. maxmax


----------



## Joshua (Sep 16, 2002)

Damn!
Does that mean I shouldn't shine it on any part of, say, my hand or anything? Will it hurt my skin? I know better than to stare at it, even for a second. How dangerous are we talking about here?
----Josh----


----------



## The_LED_Museum (Sep 16, 2002)

The Roithner LED only generates between 30 and 100 _micro_watts (0.03mW - 0.10mW) of radiation centered at 350nm. This is very weak even compared to Nichia's dim 370nm (1.0mW) or Cree's NUV (10.0 - 12.0mW) lamps.
At normal range, the danger to fingers, hands, arms, etc. should be minimal, but you should avoid looking down the barrel without a filter that attenuates the long UVB and short UVA range.


----------



## sunspot (Sep 16, 2002)

Thanks Craig. You da man. I bid on some Cree LED's on ebay today. 10 for $7.00. 405nm UV Purple.


----------



## Joshua (Sep 16, 2002)

Oh I bought me some of those too. I should be geting 10 more 400-405nm UVs Wed via Ebay.Hey Craig, will the 350n make UV glow inks and UV phosphors glow brightly or is it too dim for that? Can you even see the light if you tried or does it appear as a faint dim purple? I want to know before I spend that much on 1 LED. : )


----------



## sunspot (Sep 16, 2002)

Joshua. What do you do with your UV's? I have some Uranium glass coming in that I want to bottom light with UV's.
From the specs Craig posted, and I believe him, the rothner is 100x dimmer than the Cree.


----------



## The_LED_Museum (Sep 16, 2002)

> Originally posted by Joshua:
> *Hey Craig, will the 350n make UV glow inks and UV phosphors glow brightly or is it too dim for that? *


<font size="2" face="Verdana, Arial">That I honestly don't know.
I've never tried this LED, nor do I have any other source of UVB to play with that has output near 350nm and isn't "polluted" with multiple UVA and visible bands. Some phosphors may not react at all if they're only NUV and long-UVA sensitive, others may go apesh*t at 350. 
Sorry I can't be of much help here.


----------



## Icebreak (Sep 16, 2002)

Would these be a viable safety device?

Someone at CPF had talked about these UV's for $5.00.
http://www.countycomm.com/light10.htm

And they offer these safety glasses:
http://www.countycomm.com/specs.htm


----------



## ElektroLumens (Sep 16, 2002)

> Originally posted by Icebreak:
> *Would these be a viable safety device?
> 
> Someone at CPF had talked about these UV's for $5.00.
> ...


<font size="2" face="Verdana, Arial">I have some inexpensive sun glasses, which are UV protection rated. They do seem to filter out the UV light. I put some UV sensitive marking on a piece of paper. When I shine the UV LED's at the writing, it flouresces. But when I shine the light through the sun glasses, there is no flourescence. If I put the LED's right up to the glasses, and up to the writing, there is a small amount of flourescing. So sun glasses will filter out most of the UV light. No need to spend a lot of money. Of course, I'm sure there are different levels of protection.

Working in an office, with flourescent lighting, has a fair amount of UV light. There are other sources as well. UV light causes a gradual decrease in the quality of our eyesight. Sunlight has a lot of UV light, and sunglasses help to protect against it's effects. 

UV light is cool, but nothing to mess around with.

Infrared can also cause some damage, but it's effects may not be permanent.

Wayne J.
www.elektrolumens.com


----------



## The_LED_Museum (Sep 16, 2002)

Infrared causes mainly thermal damage, while UV can initiate a permanent molecular dissociation in various chemicals that make up the eye's components. At higher energies (moving into the UVB), this dissociative destruction can extend to the atomic level as well, breaking apart more stable compounds that a longer UVA wavelength might not touch.

The main risks to the eye involve the lens and the cornea; both of them can become cataracted (cloudied-up) with exposure. While a brief, high-intensity exposure to UVA, UVB and long UVC can cause a temporary cataract ("snow" blindness, welder's eye), longer, repeated exposure can cause cumulative damage that could become irreversible. Protiens making up the lens and cornea become torn apart and change their chemical and optical properties as a result.

Symptoms of acute UV overexposure include a burning or "sand in the eyes" sensation, a fuzzy aura or halo around light bulbs and other light sources, and photophobia; or eye pain & sensitivity when entering a brightly-illuminated area. Symptoms of reversible, acute UV exposure can take from several minutes up to several hours to appear, and up to 48 hours to clear up.

I do not know what the symptom set for long-term damage would be other than a brownish appearance to white objects (indicative of pernament lens damage, nuclear cataract, etc.) and a general haziness about everything that doesn't get better within a few days, which is indicative of a permanent corneal cataract.


----------



## Albany Tom (Sep 16, 2002)

Thanks for all of the information. 

I actually had a UV LED help protect my vision. The glasses I wear are supposed to provide UV protection. Well guess what? They let enough UVA (395nm LED) through to light up a money stripe. Now I'm shopping for better glasses...

Does anybody know if you can get a tan from a 395nm LED?


----------



## ElektroLumens (Sep 16, 2002)

> Originally posted by Albany Tom:
> *Thanks for all of the information.
> 
> I actually had a UV LED help protect my vision. The glasses I wear are supposed to provide UV protection. Well guess what? They let enough UVA (395nm LED) through to light up a money stripe. Now I'm shopping for better glasses...
> ...


<font size="2" face="Verdana, Arial">I have read that it is the UVA that gives the tan. However, at such low levels of light? First, the tan, then the sun spots and wrinkles. Will make a person look really nice, huh?





Wayne J.


----------



## sunspot (Sep 16, 2002)

At the factory shop where I made aluminium doors and had to weld them, at times I welded for two days straight. At the end of the day(s), I would be sunburned and my eyes had the "sand in the eyes" feeling. In 1972, I knew nothing about UV. It was just part of the job. I am now a big safety advocate.


----------



## Joshua (Sep 17, 2002)

I gotta try that and see and try and post some pictures here. If the LED is too dim to show up on camera then maybe it will show up on a phosphor that reacts to under 365nm. Either way I will let you guys know.
Dana, where did you get that kind of glass? That sounds bad ***! I just bought mine to go into my Knight Rider conversion car. (on the dash and inside the vents) As well as keeping some for some PCB projects in the future. And lets not forget our 405nm Photon models lying around...lol!


----------



## sunspot (Sep 17, 2002)

It is also called Vaseline glass. Check this out.


----------



## INRETECH (Sep 17, 2002)

I purchased 4 of them, and the light output is VERY low - 30uw (Microwatts)

You can see a tiny-tiny bit of greenish-white light with your eye, but you must understand that the LED is beyond your normal eyesight - and you could be damaging your eyes without knowing it..


----------



## Joshua (Sep 17, 2002)

INRETECH,
How does it do with flouescents or neon colors Do you have to get right up on it like an inch away for it to glow? Or will it glow it from distance?


----------



## ElektroLumens (Sep 17, 2002)

> Originally posted by sunspot:
> *There are different levels of UV. UVA, UVB and UVC. 350nm is getting into the danger zone. Harmful to all living organisms.
> Check this out. maxmax*


<font size="2" face="Verdana, Arial">UVA is from 400nm to 320nm. UVB is 290nm to 320nm, and UVC is below 320nm. UVA is what causes a suntan, and cause slight skin damage. UVB is what burns our skin. UVC is damaging to all life forms. UVC never makes it through our atmosphere. All UV light is damaging to our eyes, and even slight exposure to these high intensity LED's can cause eye damage.

I purchased some flouresing fingerprint powder. I have some 395um LED's. Makes the powder glow. I tried to take some fingerprints, but ended up getting the glow powder all over myself. When the UV flashlight I have shined on me, I had glowing orange all over.





Some minerals flouresce, some under long wave uv, some under short wave uv. Some mining is done using UV light to identify mineral presence. Some diamonds will flouresce, and some other precious minerals too.

If you get some UV LED's, be really careful not to look at them directly, or to shine them in others eyes. UV light damage is permanent!

Wayne J.
www.elektrolumens.com


----------



## sunspot (Sep 17, 2002)

Thanks Wayne. I knew about the different UV's but I did not know the freqs. I have some minerals at home that don't look like anything special until put under UV.

When I want to "SEE" the color output on an UV light, I shine it on white paper. Never to the eye. I already have some damage done to me from leakage on welding helmets.


----------

