Aixiz modules - glass or plastic ?

[SenKat]

Let's discuss some of the good and bad points we have found out about the glass and or plastic optics for the Aixiz modules, and some possible solutions ! I have done nothing with my new modules yet beyond putting a glass lense in an IR module I made a long time ago - I did not notice any improvement - most likely since I was viewing everything via a IR webcam to protect my vision ! I'll hang out and see what others post !

 

[yuip]

I didn't really use my acrylic lensed modules (well, I used one and blew the diode) and I thought they were okay, but I didn't like the fact that you weren't getting all of the light from the diode. And I noticed the divergence kind of sucked. No offense to dr_lava though, these were pretty good for the price.

I love that when I pick the module up the lens never fogs up (like on the acrylic lensed modules) and the AR coating is awesome. The full input window is exactly what I wanted.

I haven't put a diode in my glass lensed modules yet, but they look to be well worth the little bit of money extra compared to the acrylic lensed module.

Hey Greg, if you ever get anymore of the glass lenses, shoot me a line and I'll probably pick 3-5 more lenses. (not the whole module, already have 7 of those)

Thinking about it, I probably should have just bought the glass lenses minus the module in the first place. Oh well, still worth every penny!

 

[Hemlock Mike]

I was going to start a post like this so here's what I found ---

I got 5 Aixiz modules with plastic lenses PLUS 5 separate glass inserts.
I modded one installing an Opnext HL6545MG diode. Set the current to 350 mA !!

With the basic plastic assembly -- Output 245 mW.
With the glass assembly --- 260 mW :-( I was looking for 300 mW.
Modded the plastic lens by opening the little apperture a bunch and --- 295 mW !!

It appears that the glass assembly focuses too far from the LD source and and optics need to be CLOSE to the LD window or "spillage" is lost energy. The plastic lens assembly seems to get real close to gather more output which is a rectangular beam. I tried the glass assembly both ways and one way is just a little better than the other. All this with the above diode.
I have not melted the plastic optics either. Perhaps an IR diode would have a tighter output and work better with that wavelength with the glass optics. I may also try cutting the "top hat" off a diode to get it ALL !!!!

Mike

 

[Corona]

Interesting!

The one application where the acrylic lenses are at a big disadvantage is violet lasers; the plastic fluoresces like crazy and adds a nasty bloom to the beam profile.

I don't have any of the Aixiz glass lenses yet, so I can't compare them, but the plastic one works great for DVD reds in burning stuff - the divergence is not very good at all but the benefit is that the focus can be adjusted to a VERY sharp spot - it looks a lot bigger than it is - when viewing it while burning, it looks like maybe 1-2mm but when a burn hole is inspected, it's much smaller - something like 0.1mm.

 

[Hemlock Mike]

Corona --
You got that right -- It's hard to adjust the red for that pinpoint burn !! Just too bright so I made marks on my focus ring like a camera.

The glass assembly has three lenses inside plus a spacer. I think a little is lost every time you go through a lens.

Mike

 

[Bimmerboy]

Senkat - Instead of bringing the other thread back up, I'll respond here to your offer to relace the poorly threaded items by saying thanks! It's certainly appreciated, although I'll only bother you about it if they're truly problematic... as in 'unusable'. Even if that's the case, I'll try contacting Aixiz about it first.

So peeps know what I'm talking about, this is in reference to the lousy threading on some of these items. I got two glass modules... and the lens holder on one doesn't want to screw all the way in, the end caps on both won't screw onto the other side more than a couple turns, and one of the end caps refuses to go on straight, like it's permanently cross-threaded or something.

Yes, these are cheap, "get what you pay for" kind of items, but I'd submit that the threading could at least be a little cleaner.

Corona - Noob question about optics... since these are focusable, aren't they in essence, adjustable divergence? For example, wouldn't focusing as tight a dot as possible on a long distance target, produce a good divergence? Quite sure I'm missing something with this question, but figured I'd ask.

Mike - Interesting what you're finding. I'm gonna' try that mod on a plastic one and compare. No equipment though, so not sure if I'll be able to tell differences by eye.

 

[SenKat]

Naw - come through me, first you are the end user, but I distributed them - I shoulda caught that. Seriously ! I have no problems replacing the messed up ones

Hmmm...I thought there were two lenses, not three ! If that is the case, then they very well could be diverging optics - which would explain the issues with getting them to focus to a dot !

 

[Corona]

Noob question about optics... since these are focusable, aren't they in essence, adjustable divergence? For example, wouldn't focusing as tight a dot as possible on a long distance target, produce a good divergence? Quite sure I'm missing something with this question, but figured I'd ask.

Yes in essence, the adjustable focus should allow you to get a tight spot up close at the expense of divergence and a good divergence at the expense of up-close spot size.

Not sure why there's 3 lenses, a simple collimator consists of a concave beam expander followed by a convex focusing lens. Probably to shorten the focal length of the assembly they added another plano-convex lens (one side flat, the other curved).

And Mike really hit on another disadvantage of these glass sets, the refraction and transmission losses from the multiple elements do result in additional losses through the system. And the focal length (distance from the diode and spacing between elements) of the system tends to be longer as well, compared to the plastic ones, because the plastic lens is cast as a single aspheric element - which is a real bear to do in glass. It can be (and is) done, but it's way expensive. So the plastic lens theoretically has superior characteristics, since it's an engineered piece and the optical parameters can be easily manipulated. It seems that the designers of the Aixiz plastic collimator have chosen to sacrifice good divergence for a very short focal length (capturing the maximum amount of light energy and/or keep the module size very small).

 

[Hemlock Mike]

Bad threads ??? BAD threads. I found that too. The plastic is OK but the glass assemblies need light filing over their threads to fit good. I ruined one set befor I figured it out. I use a flat diamond needle file but other abrasives to remove a couple thou would work. Clean the threads after filing.

Mike

 

[Bimmerboy]

A bit slow in replying, but thanks to all three of youse guys.

So, has anyone been playing with their glass modules? Haven't gotten to mine yet. Interested to see if there's a noticeable difference in beam diameter compared to the plastic, and also if there's a difference in visible brightness across the beam length.

Senkat - Sending PM, but about a different subject. :kiss: LOL... just kidding!

Mike - Yeah, the plastic barrels (lens holders) are fine... in fact, they're perhaps a bit too smooth. I had to score the threads in 3 places to stiffen the action up a bit, or it would change focus with the slightest touch.

Corona - Interesting point regarding the casting. Also not crazy about the transmission loss of three elements. If ya' pay through the nose for quality, I'm sure the effects are minimized, but who wants to pay through the nose?

It'd be nice if Aixiz published some specs on any of their units.