Even Flood beam for 365nm (UV)

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purduephotog
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Even Flood beam for 365nm (UV)

I’ve been trying to find a host for several UV chips that are at 360-365nm. I can’t use anything with polycarbonate (lexan) because it absorbs strongly. Certain other plastics have good transmittance but I haven’t found TIR optics made with them.

That leaves metallized reflectors, capable of fitting a 7070 chip on a 20mm star.

Any diffusion films on the output again need to be chosen for transmittance at 365nm as well- mostly glass at that point.

Any suggestions?

djozz
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Not sure what is the question.

If you want diffusion, you could consider frosting the glass lens. If you have access to that, you can sand blast it, and I have had reasonable succes with extensive sanding with sand paper.

keltex78
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Have you considered setting up as a mule with no optics? That would give you a wide/even flood…


Keepin’ the “B” in BLF

Don wrote:
It sounds like the XM LEDs won’t really be suitable for flashlight use. Pity…

purduephotog
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Glass does have some absorption and does a number on efficiency. It’s hard enough to get high UV numbers without adding a diffuser that scatters and induces losses.

Ideally I’d use a TIR that can beam shape to 60 degrees evenly, but then I run into absorption of the 365nm wavelengths unless some exotic plastic is used.

The hard part is the 7070 footprint- this is very large (it is a 4 die).

purduephotog
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I had- that’s your general flood, but then there is significant falloff along the edges without any useful UV being put on subject. If I could find a 60 degree that was evenly lit/flat, that would be ideal.

alpg88
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purduephotog wrote:
Glass does have some absorption and does a number on efficiency. It’s hard enough to get high UV numbers without adding a diffuser that scatters and induces losses.

Ideally I’d use a TIR that can beam shape to 60 degrees evenly, but then I run into absorption of the 365nm wavelengths unless some exotic plastic is used.

The hard part is the 7070 footprint- this is very large (it is a 4 die).

yes glass does drop output a bit, but in most cases we can’t have no glass, so it is a necessary evil.
pmma does not absorb 365nm, i looked for lens that would work with 365nm. no acrylic, or polycarb will do. you need pmma tir. ledil makes pmma 20mm triple, ledengin makes tir specifically for 365nm. iirc in few sizes.

keltex78
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I’ve been looking for this link for a while but just found it… It’s a test Djozz did a couple of years ago, with UV transmission through different materials…

http://budgetlightforum.com/node/37212?page=2#comment-719507

…The PC Carclo optic seems to be opaque to UV…

I was able to build a fairly floody UV light using a junk triple host that had individual reflectors for each 3535 emitter, with glass lenses, but having the 7070 emitter would be more difficult on a budget…

Not sure about the emitters you are using, but if we could find something like the G36 triple to use as a host:
http://budgetlightforum.com/node/42278
…with some OP reflectors, it might make a nice floody light… A triple 7070 UV flood-monster. With some UV-pass filter lenses. Do NOT take into the hotel with you… Oops


Keepin’ the “B” in BLF

Don wrote:
It sounds like the XM LEDs won’t really be suitable for flashlight use. Pity…

purduephotog
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alpg88 wrote:
purduephotog wrote:
Glass does have some absorption and does a number on efficiency. It’s hard enough to get high UV numbers without adding a diffuser that scatters and induces losses.

Ideally I’d use a TIR that can beam shape to 60 degrees evenly, but then I run into absorption of the 365nm wavelengths unless some exotic plastic is used.

The hard part is the 7070 footprint- this is very large (it is a 4 die).

yes glass does drop output a bit, but in most cases we can’t have no glass, so it is a necessary evil.
pmma does not absorb 365nm, i looked for lens that would work with 365nm. no acrylic, or polycarb will do. you need pmma tir. ledil makes pmma 20mm triple, ledengin makes tir specifically for 365nm. iirc in few sizes.

Ledengin- I’ll go look at their optics. I was striking out with the Carclo optics as they were all opaque. I hadn’t had any luck finding PMMA optics until this note- thank you.