2mm ZWB2 filter tested (visible light blocking filter suitable for 365nm UV flashlights)

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Spiderlight
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pirateo40 wrote:
Just reread this post – forgot to update -sorry. Upon further investigation I was told that AR coatings are not really efficient for UVA and result in a significant transmission loss, so I just dropped it (sadly don’t remember the details). Of course I’m sure there are specialty houses which can create very efficient coatings, but at a very inefficient price (I was quote a couple hundred for one piece, and a setup charge as I remember).

Thank you for the update.
nzoomed
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Been looking on aliexpress and there is a bunch of sellers of the stuff there.
Is this glass required for an LG3535LED? I bought it assuming it was much better than a chinese brand in regards to the visible light output.
Specs on the LED are 380-385nm, but i see other sellers selling it under different wavelenghts and I question whether or not hose ones are genuine.
I cant find any datasheet from LG either.

Scientist
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The filter is for eliminating visible light. The Nichias emit the least with others emitting somewhat more. The cheap ones are the worst. You will enjoy the light more if you get the inexpensive filter. ,

Please illuminate responsibly
Part time fragmented conciousness technician

UV triple using Sofirn C8F
395nm High Power LED in Sofirn SC31b

wle
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i found them to work but they are very susceptible to breaking and chipping

i think the glass is soft, somehow

wle

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Judging by the various price ranges for ZWB2 filters, i assume they’re not all the same quality.

wle
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true, and quality may not be entirely defined by glass hardness, either
mine were certainly cheap

wle

"You never have the wind with you - it's either against you, or you're having a good day."
    Daniel Behrman, "The Man Who Loved Bicycles".
It never gets easy, you just go faster.   
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nzoomed
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Scientist wrote:
The filter is for eliminating visible light. The Nichias emit the least with others emitting somewhat more. The cheap ones are the worst. You will enjoy the light more if you get the inexpensive filter. ,

Yes im aware of that, I was trying to work out if the LG3535 puts out excessive visible light compared to the cheap chinese LEDs on the market.
Im wanting to use it on uranium glass most of the time and the odd time to cure UV resin.
wle
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i’m a uranium glass guy

i have found one hack for that, for testing it in the field, a cheap purple laser has tons of UV
you can even use it in day light
which no flashlight alone can overcome

lights it right up

wle

"You never have the wind with you - it's either against you, or you're having a good day."
    Daniel Behrman, "The Man Who Loved Bicycles".
It never gets easy, you just go faster.   
-Greg Lemond.
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nzoomed
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wle wrote:
i’m a uranium glass guy

i have found one hack for that, for testing it in the field, a cheap purple laser has tons of UV
you can even use it in day light
which no flashlight alone can overcome

lights it right up

wle


Yes ive been over in laserpointerforums and quite a few are doing that with purple lasers.
Im currently building a blue laser with an M140 diode.
Will need to build a purple/violet laser to get the UV, i dont think 445nm lasers produce any.
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Jerommel wrote:
Judging by the various price ranges for ZWB2 filters, i assume they’re not all the same quality.

+1

My current ZWB2 filter supplier is KD, good quality and has several sizes.

hank
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Quote:
Im currently building a blue laser with an M140 diode. Will need to build a purple/violet laser to get the UV, i dont think 445nm lasers produce any.

Be very careful around other people with those, both direct and specular reflections.

The human eye is just barely sensitive to those wavelengths, which means it takes a heck of a lot of photons before your visual system tells your brain it’s seeing anything. But just because you can barely perceive the light output doesn’t mean it’s not transferring a lot of energy to the retina.

This should help: http://www.komar.org/faq/colorado-cataract-surgery-crystalens/ultra-viol...
He had cataract surgery and was given intraocular lenses that don’t block UV, so he can see what most people cannot.

Quote:
December 19th, 2011 Update: I picked up 400nm and 365nm UV flashlights to “test” my vision more. While both have some leakage into the visual spectrum (above ~400nm), the 365nm light is a faint/pale grey to “normal” people … whereas I see a bright purple. So it makes for a very easy demonstration of my ability to see UV. Ironically, the 365nm UV flashlight did not have a warning sticker on it, although it would be more dangerous ….
nzoomed
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hank wrote:
Quote:
Im currently building a blue laser with an M140 diode. Will need to build a purple/violet laser to get the UV, i dont think 445nm lasers produce any.

Be very careful around other people with those, both direct and specular reflections.

The human eye is just barely sensitive to those wavelengths, which means it takes a heck of a lot of photons before your visual system tells your brain it’s seeing anything. But just because you can barely perceive the light output doesn’t mean it’s not transferring a lot of energy to the retina.

This should help: http://www.komar.org/faq/colorado-cataract-surgery-crystalens/ultra-viol...
He had cataract surgery and was given intraocular lenses that don’t block UV, so he can see what most people cannot.

Quote:
December 19th, 2011 Update: I picked up 400nm and 365nm UV flashlights to “test” my vision more. While both have some leakage into the visual spectrum (above ~400nm), the 365nm light is a faint/pale grey to “normal” people … whereas I see a bright purple. So it makes for a very easy demonstration of my ability to see UV. Ironically, the 365nm UV flashlight did not have a warning sticker on it, although it would be more dangerous ….

Yes, Im aware of the dangers with lasers. As long as you are not pointing on shiny objects in the near field of view, its quite safe.
My laser can also focus like a flashlight with a wide throw, which reduces the danger completley. This makes them perfect for shining on uranium glass.

Right now, im more concerned about the dangers of UV lights.
Seems you are supposed to wear glasses for these too, which I dont fully get, since its all UV-A, which is supposed to be the “safer” part of the spectrum.
This cheap light I got from the electronics store says it can be used as a fun kids toy! Yes im serious, says to use for spot light games, etc.
Ive also been to many public events where you can see the UV blacklight tubes glowing that magical violet directly. One place I saw they were using the 365nm tubes once as they were not the typical black colour. I didnt know anything about this at the time, since I was just a kid and thought it was fun lol.
Not that ive intentionally looked into it, but have accidentally shone in my face when handling it a couple of times.

From what Ive researched, we are exposed to way more of this same part of the UV spectrum each day from the sun, so im not too sure how dangerous this cheap 3W light of mine is. I expect it would be around 395nm.

Its interesting read in that link of yours.
I did not know our eyes started to block out more UV with age. I guess this is a built in means of protection, a bit like how your skin makes melanin with UV exposure?

Jerommel
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The lenses in our eyes develop an amber filter over the years.
This is a degradation rather than a feature.
But it does make the world look a bit warmer, i suppose..

hank
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The comparison to sunlight fails because sunlight isn’t a point source.

When the eye focuses the image of a UV source, all the photons are delivered to a small area of the retina.

nzoomed
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hank wrote:
The comparison to sunlight fails because sunlight isn’t a point source.

When the eye focuses the image of a UV source, all the photons are delivered to a small area of the retina.

Well the sun is too, so I assume getting sunstrike while driving would be similar effect?
Either way, they should not sell these lights as kids toys with no warnings if they are that dangerous.

Dont get why they are saying to wear glasses while using them if you are not looking into the light anyway.
Are they that dangerous?

I see videos on youtube saying to wear the glasses while shining on uranium glass, yet ive seen these same UV lights at nightclubs, bowling alleys with the direct source visible with way more power than a little 3W LED.

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nzoomed wrote:
hank wrote:
The comparison to sunlight fails because sunlight isn’t a point source.

When the eye focuses the image of a UV source, all the photons are delivered to a small area of the retina.

Well the sun is too, so I assume getting sunstrike while driving would be similar effect?
Either way, they should not sell these lights as kids toys with no warnings if they are that dangerous.

Dont get why they are saying to wear glasses while using them if you are not looking into the light anyway.
Are they that dangerous?

I see videos on youtube saying to wear the glasses while shining on uranium glass, yet ive seen these same UV lights at nightclubs, bowling alleys with the direct source visible with way more power than a little 3W LED.

The blacklight you see in nightclubs (?!?) is the longer wavelength form of UV light, plm.400nm and is visible. This is the thread about ZWB2 filters, who are used to block as much visible light as possible. And pass 365 nm UV light. This type of light you cannot see (directly). Any user of such light has experienced the uncorfortable feel of welders eyes when he/she did not pay enough attention to where he/she was shining his/her light. Even for a brief moment!
So we are talking about two different items.
It’s like saying russian roulette in general is childsplay because 84% of it is only a soft click.

You are a flashaholic if you are forced to come out of the closet, to make room for more flashlights.

nzoomed
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Henk4U2 wrote:
nzoomed wrote:
hank wrote:
The comparison to sunlight fails because sunlight isn’t a point source.

When the eye focuses the image of a UV source, all the photons are delivered to a small area of the retina.

Well the sun is too, so I assume getting sunstrike while driving would be similar effect?
Either way, they should not sell these lights as kids toys with no warnings if they are that dangerous.

Dont get why they are saying to wear glasses while using them if you are not looking into the light anyway.
Are they that dangerous?

I see videos on youtube saying to wear the glasses while shining on uranium glass, yet ive seen these same UV lights at nightclubs, bowling alleys with the direct source visible with way more power than a little 3W LED.

The blacklight you see in nightclubs (?!?) is the longer wavelength form of UV light, plm.400nm and is visible. This is the thread about ZWB2 filters, who are used to block as much visible light as possible. And pass 365 nm UV light. This type of light you cannot see (directly). Any user of such light has experienced the uncorfortable feel of welders eyes when he/she did not pay enough attention to where he/she was shining his/her light. Even for a brief moment!
So we are talking about two different items.
It’s like saying russian roulette in general is childsplay because 84% of it is only a soft click.

From what I understand, most 400nm lights still produce a certain amount of shorter wavelengths just like a 365nm LED produces visible light. You can install a ZWB2 filter on such a lamp and you will see what I mean, it’s just that a 400nm LED produces much less of the shorter wavelength UV, well that’s what I understand.
My main concern was that I’ve seen warnings on some 400nm lights.
I will be obviously more careful around them but I don’t currentlyown a 365nm light, but as far as I know it’s still safe to use them without glasses as long as you don’t look into the light source, but still have common sense and don’t shine into eyes.
I’ve definitely seen 365nm tubes used in public events, as the glass was not black when turned off. I see one company advertising 365nm for this purpose as a better light with less visible purple spoiling the effects!

Just been on here and since 365nm is still UVA, it’s not in the dangerous part of the spectrum.
This link was an interesting read.

https://www.waveformlighting.com/tech/everything-you-need-to-know-about-...

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That link is a nice nuanced summary of how to deal with UV-flashlights! Smile

flightless22
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I found this ebay listing for ZWB2 5 pack of 12mm x 1.0mm for $7 + $7shipping from China

Would the ZWB2 cut well with these diamond cutters ?

hank
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Did anyone fit a suitable filter to the old stainless steel 2-emitter “BLF Special 400nm/365nm Edtion” light?
That’s the one with the dragon etched on the battery tube.
I wasn’t sure what wavelengths I want to filter out when using that.

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flightless22 wrote:
I found this ebay listing for ZWB2 5 pack of 12mm x 1.0mm for $7 + $7shipping from China

Would the ZWB2 cut well with these diamond cutters ?


I found the ZWB2 glass rather brittle, I could not get it cut nicely with a glass cutter, and knibbling bits off with pliers did not work either.

hank wrote:
Did anyone fit a suitable filter to the old stainless steel 2-emitter “BLF Special 400nm/365nm Edtion” light?
That’s the one with the dragon etched on the battery tube.
I wasn’t sure what wavelengths I want to filter out when using that.

The ZWB2 filter is only useful for 365nm leds, apart from 365nm light they emit a broad white-ish band in visible light too interfering with fluorescence light. The filter’s transmission peak is at 365nm and blocks all visible light so it gets rid of the white-ish stray light.

It is no good for 400nm leds, 400nm leds do not have the interfering white light, just the 400nm peak so there is nothing sensible to filter out. Moreover the ZWB2 filter blocks a lot of 400nm light so it weakens the led.

hank
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Thanks djozz

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