# UV leds that are totally invisible for naked eye?



## CuriousOne (Jul 18, 2013)

Hello. I'm doing the patio refurbishment, and I want to draw some fancy figures on it using glow in the dark paint. The paint reacts to UV, so I want to hook a series of UV led to illuminate the paint for glow. The problem is, most UV leds I bought, are pretty well visible to naked eye. So maybe there are leds that emit the "hard" uv light? just like black light bulbs? even 3mm ones will be enough.


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## arek98 (Jul 18, 2013)

Use 365nm LED's or Wood's glass filter to cut off visible light.


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## AnAppleSnail (Jul 19, 2013)

Please consider the possibility of permanent eye damage. UV LEDs, even low-powered ones, can harm your eyes. UV LED Safety Page at one site.


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## Yoda4561 (Jul 27, 2013)

365-375 NM should do what you want. The problem with them is even small impurities in the LED dome or other nearby components will fluoresce slightly making them give off a small amount of white/greenish light. Woods glass filters are the best solution. Avoid "camera" type UV filters as these filter out UV instead of visible light, the opposite of what you want.


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## Revolvr (Jul 28, 2013)

Yoda4561 said:


> 365-375 NM should do what you want. The problem with them is even small impurities in the LED dome or other nearby components will fluoresce slightly making them give off a small amount of white/greenish light. Woods glass filters are the best solution. Avoid "camera" type UV filters as these filter out UV instead of visible light, the opposite of what you want.



I'll second that. I've tried a few 1W UV LEDs off flea-bay, all from China, and all were next to worthless. One was advertised as 390-400 but wouldn't fluoresce much of anything. Contacting the seller, he said yea, they were really 410+. Another advertised as 380-385nm, may actually be giving off some light at that wavelength, but is doing just what you describe, giving off a good amount of white light. Nearly worthless.

If anyone knows where I can get quality 1W UV LEDs from say 380-395nm, I'd love to know. This is for a scorpion light, and they fluoresce well at anything below 395nm.


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