UV filter?

[kramer5150]

Is it possible to get UV light out of a non-UV LED by filtering the output?

thanks

 

[MrGman]

No, there has to be UV in the source spectrum and then you would filter all of the visible light out. You can't filter "in" something that isn't already in the original spectrum.

You can buy a UV LED module for 20 bucks at lighthound.com and drop it into any 6P type host.

 

[kramer5150]

Oh... DUH... I hadn't thought of it that way.

LOL

thanks:thumbsup:

 

[Search]

Hence why IR filters only work on incandescants.

They don't produce the IR, they filter only the IR radiation.

 

[steveG]

I'm confused about a few things....

When people say "UV filter", are they referring to an "excitation filter"?

Earlier today one of the mechanics at work was using a UV filter on his incandescent Streamlight to look for a leak in an A/C system (dye added). Just for kicks I put the filter over my E2DL and shined it on the dye. It lit up like mad! Much brighter than with his incandescent. I also tried it on my U2A and it was almost as bright as the E2DL.

I immediately wanted a filter for my E2DL or U2 but haven't found any and had no luck here on CPF.

So what's the deal?

 

[MrGman]

the filter he was using and you then played with was not creating UV. It was filtering out all of the visible light spectrum so that only the UV would remain and therefore anything that fluoresced from the UV would not be washed out in lots of visible light. An incandescent light source has very very little UV in it unless it is over driven. A Light Emitting Diode flashlight which is a blue LED source and then phosphor coatings to make white light has more UV in the actual output of the blue LED than an incandescent. Just as many of the UV light source LEDs spill over into the visible blue range. so putting the filter in front of your LED lights and blocking all the white light you saw the effects of the UV light from you source causing the dye to fluoresce more so than the incandescent light.

The filter was not converting visible light wavelengths into UV light. Hence the incan light was very poor at making a UV source. Did your friend want to get a LED flashlight?

You can buy a Solarforce UV LED module for $20.00 that drops into any p60 compatible light. With a UV filter in front of that it will block out the little bit of purple/blue light in the visible spectrum and be very good to see fluorescing dyes with.

 

[steveG]

the filter he was using and you then played with was not creating UV. It was filtering out all of the visible light spectrum so that only the UV would remain....

I knew that much. I guess I was under the impression that LED lamps emitted little UV light... I think I was confusing it with IR, though.

Did your friend want to get a LED flashlight?

Haha, yes. He'd looked at the LED conversions before but didn't want to spend the money since his incandescent had been getting the job done just fine for years. He's thinking about the LED conversion again.

You can buy a Solarforce UV LED module for $20.00 that drops into any p60 compatible light. With a UV filter in front of that it will block out the little bit of purple/blue light in the visible spectrum and be very good to see fluorescing dyes with.

I might pick up a UV module, but I'd rather just buy a filter for the light I already carry and keep at (E2DL). Do you know of any? Or a larger filter I could cut to fit one of my current slip-on filters?

Thanks for the info!

 

[MrGman]

Since I have real UV lights at work, I have never investigated sources of UV filter materials, sorry.

 

[Moonshadow]

If you want UV, then you are far better off with a UV LED to start with

Photon Freedom Ultra Violet (http://www.photonlight.com) will cost you less than a UV filter and produce a lot more 370nm goodness than a filtered light.

Got a covert nose, too.

 

[Patriot]

Or go the way that Gman already suggested since it will be far brighter than any 5mm UV emitter.

MrGman
You can buy a Solarforce UV LED module for $20.00 that drops into any p60 compatible light. With a UV filter in front of that it will block out the little bit of purple/blue light in the visible spectrum and be very good to see fluorescing dyes with.