Nice review of these filters, thanks.

I got my filter today and for some reason thought it would be plastic, only realised it was glass when i tried to cut it with a hacksaw

I ordered this for my UV Ti which has a 12mm window.
Not going to be as easy as i thought modding this, so out with the diamond disc dremmel instead.

Took some careful time grinding but i got it in the end
Looks cool with the dark glass and does make a difference in visible light output.

No, and i even wore safety glasses. I bought the emitter from Ali ex ages ago, just a cheap one to try out.
I can’t seem to find the one i bought but it is one like this

I used the piece i had left over to stick on my Mecarmy SGN3. It’s borg ugly but it works.

The filter can be bought at simons shop
https://www.aliexpress.com/store/group/glass-filter/330416_507487979.htm...

Works great with Nichia UV LED
Both pictures with same camera exposure the filter kills almost all visible light

What about 365nm LEDs ?
Does anyone have a good source (apart from LED4POWER) for a good quality UV LED ?

A little late to this thread, but just in case anyone is still around….
I noticed a significant amount of reflection from the ZWB2 filter. Did some investigating into AR coatings and got back ridiculous prices. So I emailed Simon and he said the factory could do it at a very reasonable cost.
Any thoughts? My research shows that a 10% to 20% improvement in output might be expected….

djozz wrote:

I’m around
That is a lot of improvement, so reflection on the glass surfaces from UV is worse than with white light, and so there is more to fix for the AR coating!

Nice of Simon that he is willing to do that, I’m certainly in for some of those if the price is reasonable, AR-coated ZWB2 filters should look cool too btw.

Here’s a graph showing one company’s projected improvement

That would be cool, what would be phenomenal would be to get some 12mm & 10mm sizes made too.

^

And SRK/Maglite size.  I want to make a UV multi-emitter.

Also, interested in the A/R coating aspect, but different sizes more.

I’m interested in a couple at least. I have two Nichia NVSU233A-U365 1030mW chips on the way right now. My first uv emitters so I’m trying not to get too excited.

Anyone found a source for larger than 20.5mm diameter lenses? I want to build a multi-emmiter light or even maybe a 365nm C8, because, why not

Looked on AX, only sheets for a few hunnert bux each.

I wanted some for a ’501 or ’502, ‘though yeah, a C8 would be nice!

Pardon a dumb question. I ordered a set (2pcs) of ZWB2 filters from Simon’s Convoy store in AliExpress and it just arrived a few days ago. I’m wondering when I place the ZWB2 filter inside the Convoy S2+ UV Nichia flashlight, can I place it behind the existing plain glass lens (which is what I just did — so it has a plain glass lens in front, and the ZWB2 filter just behind it), or do I need to remove the plain glass lens altogether (ie. only the ZWB2 filter)?

When shining some other light on the ZWB2 filter, it looks like it has concentric circles/rings, though I don’t notice the concentric rings when using the Convoy UV w/ ZWB2 flashlight..

d_t_a wrote:

When shining some other light on the ZWB2 filter, it looks like it has concentric circles/rings, though I don’t notice the concentric rings when using the Convoy UV w/ ZWB2 flashlight..

Yeah, when 2 pieces of glass get close enough that there’s a very small air-gap, you get funky optical properties. Some places would be in contact, some places would have a clear air-gap, others would be in that twilight zone in-between where it’d essentially be a vacuum (ie, other than maybe H₂, no molecules would be able to fit.

So what you’re seeing is a sort of standing-wave of the 2 distinctly different interfaces: glass–glass, glass–air, and glass–vacuum, and the different refractive funkiness of each zone.

That’s why I don’t even like to keep the original glass when refitting with a TIR. Weird things can happen.

—

Oh, wait a sec… you mean just the nekkid ZWB2 filter and no other glass on/under it? Hmm, never really noticed that. Will have to look.

djozz wrote:

^ ah, now I see what rings were meant (they are called Newton rings, an interference effect between layers close to each other, close to parallel but not exact.)

Ah, good. I was hoping someone’d remember what they were called. I was drawing a blank.

djozz wrote:

^ ah, now I see what rings were meant (they are called Newton rings, an interference effect between layers close to each other, close to parallel but not exact.)

^^ Learned something new today. Yes, Newton rings are indeed what I’m seeing.

Quote:

Newton rings — from Wikipedia —

The pattern is created by placing a very slightly convex curved glass on an optical flat glass. The two pieces of glass make contact only at the center, at other points there is a slight air gap between the two surfaces, increasing with radial distance from the center.”

Thus by placing 2 pieces of glass (the non-AR-coated glass lens and the ZWB2 filter) close together, there is indeed an air-gap between them that causes these Newton rings… I wonder which one is the slightly convex curved glass — the plain glass lens or the ZWB2 filter — more likely the ZWB2 filter?

Is the coated version still available somewhere?

djozz wrote:

Spiderlight wrote:

Is the coated version still available somewhere?

I do not understand, the coated version of what do you mean? (ZWB2 filters as far as I know are not coated).

djozz wrote:

Ah sorry, I see, I should have read some posts back, the discussion is from last year and apparently I’m so senile already that I totally forgot.

I guess Simon never went on with it and pirate stopped bugging him about it. It is not in his store at least.

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).