New Feit UV LED bulb

Wurkkos

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Hi Troy Boy,

Responding to your PM and public post at the same time. I hope you don't mind.

Yes, you need a Woods Glass filter or similar UV-pass filter. I've seen some dichroic filters that claim to have a fairly narrow 365nm bandpass, although I haven't tried one yet. They're actually silver in appearance. B&H Photo sells them in the States. They're probably more expensive than the one you saw on Alibaba though.

It bugs me a little that a 365nm LED produces multiple wavelengths, some of them visible. The whole idea is to produce an invisible light source. Some UV LEDs are even built in a plastic substrate that fluoresces white! I don't know what they were thinking there.

I'll look around form some possible filters for the CroLED and I'll let you know if I find anything good.

pw

quality 365nm UV LEDs like SST-10 UV and Nichia for example do not emit visible wastelight
just a faint purple glow as your Eye can see down to almost 380nm

ZWB2 filter is available in 21mm for common flashlight sizes
 

Troy Boy

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Aug 29, 2017
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quality 365nm UV LEDs like SST-10 UV and Nichia for example do not emit visible wastelight
just a faint purple glow as your Eye can see down to almost 380nm

ZWB2 filter is available in 21mm for common flashlight sizes

Hey,
Ad i mentioned its to go on top of a 60mm diameter globe. I went with the CroLED as it was recommended to be one of the best and cheap.

If you can link me to these other globes you mentioned, i will check them out. But with the professional type non LED ones, they dont have lots of visible purple like the LED on the black background, so thats what lead me to think it probably needs a filter

Thanks
Troy
 

Troy Boy

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I found the SST-10 you mentioned. I dont see how thats a globe? Its a square thing with a dome on it.
I wanted one i could use in a desktop lamp :)
 

Troy Boy

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Joined
Aug 29, 2017
Messages
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Hi Troy Boy,

Responding to your PM and public post at the same time. I hope you don't mind.

Yes, you need a Woods Glass filter or similar UV-pass filter. I've seen some dichroic filters that claim to have a fairly narrow 365nm bandpass, although I haven't tried one yet. They're actually silver in appearance. B&H Photo sells them in the States. They're probably more expensive than the one you saw on Alibaba though.

It bugs me a little that a 365nm LED produces multiple wavelengths, some of them visible. The whole idea is to produce an invisible light source. Some UV LEDs are even built in a plastic substrate that fluoresces white! I don't know what they were thinking there.

I'll look around form some possible filters for the CroLED and I'll let you know if I find anything good.

pw

Hey dude,

Hows the hunt for filter going?

I was thinking if i cant get that. Maybe should try some other globes? You mentioned that you had quite a few different ones, maybe you can compare them to the CroLED and see if they reflect a stong amount of purple onto a black card. I know that there is always going to be some amount of purple showing, but its so much more than the huge non led globes which is why i think maybe thats why im getting slightly different uv reactions on the inks.

Thanks for all your help
 

PhotonWrangler

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I was thinking if i cant get that. Maybe should try some other globes? You mentioned that you had quite a few different ones, maybe you can compare them to the CroLED and see if they reflect a stong amount of purple onto a black card. I know that there is always going to be some amount of purple showing, but its so much more than the huge non led globes which is why i think maybe thats why im getting slightly different uv reactions on the inks.

You know, for a moment I was considering purchasing one of those old incandescent blacklight bulbs and cutting the upper portion of the bulb off to get a globe-shaped glass filter. I thought about scoring the bulb with a glass cutter, then breaking off the top part. But then I remembered what a klutz I am with glass cutting.
:p
 

Troy Boy

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Hahaha, yeh that sounds a bit crazy.
So any luck finding a filter of any sort for me? I really have no clue what to get.
Also, how about the other 365nm globes you have? Can you see if they work better somehow? Maybe see if they project as much purple light onto black card.
Thanks
 

PhotonWrangler

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I've just ordered a Rosco Permacolor UV-pass dichroic filter # 3660 to experiment with. I should have it in a few days. I'll let you know how it works out.

**Update**

I've received a couple of these filters and tried one out on a flashlight that has the Nichia 365nm LED. The LED generates some whitish visible light as well as the UV content. The filter has some insertion loss on the UV, which I expected, however it does cut down the visible light output significantly. Based on this, I might order a larger filter to fit onto a reflector hood for the Feit bulb.

This filter is a silver colored disc, so when the flashlight is off, the lens looks like a solid mirror. :huh:
 
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