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ArcticMyst Security by Avery
DX Green Laser Focusing Lens
- Thread starter Evroni
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HIMNL9
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If you do this, you just get the beam focused at the FL distance of the aixiz lens (3 or 4 mm), then diverging quickly ..... good if you want a near burning point, but unhelpful for collimation in distance .....
HIMNL9
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Green modules are not diodes, are DPSS (diode pumped solid state) assemblies, and have output beam characteristics differents from diodes ..... and aixiz lenses have a FL (focal lenght) of 3 or 4 mm, set specifically for focus the output divergence typical of a diode, not the one from a crystal assembly of a green module .....
If you take away the cap of a green pen and put the aixiz lens in front of the output lens, the beam just become focused at the FL of the aixiz lens, then diverge again ..... you get a focus point where the beam burn, but no straight beam .....
If you remove also he front lens of the module and place an aixiz lens there, the FL of the aixiz lens is too short, and it still focus the beam near it (also if a bit more distant), then diverge again .....
The only way that you can obtain something like a collimated beam with an aixiz lens, is placing it very near to the expander, in this way you can obtain a thinner green beam, but this have 3 problems ..... first, these lens holders are usually assembled with loctite glue, and is a real pain you-know-where
to take them away without destroy the module or ruin the crystal / expander ..... second, the output diameters don't match, so you need to build a custom threaded holder for the aixiz lens ..... and third, the focusing process is a real nightmare, with these distances ..... i've tried something similar with an o-like module, and using a short FL as focusing lens, the process was so critic that for defocus it, was enough almost just look the lens bad, not speaking about moving it .....
If you take away the cap of a green pen and put the aixiz lens in front of the output lens, the beam just become focused at the FL of the aixiz lens, then diverge again ..... you get a focus point where the beam burn, but no straight beam .....
If you remove also he front lens of the module and place an aixiz lens there, the FL of the aixiz lens is too short, and it still focus the beam near it (also if a bit more distant), then diverge again .....
The only way that you can obtain something like a collimated beam with an aixiz lens, is placing it very near to the expander, in this way you can obtain a thinner green beam, but this have 3 problems ..... first, these lens holders are usually assembled with loctite glue, and is a real pain you-know-where
to take them away without destroy the module or ruin the crystal / expander ..... second, the output diameters don't match, so you need to build a custom threaded holder for the aixiz lens ..... and third, the focusing process is a real nightmare, with these distances ..... i've tried something similar with an o-like module, and using a short FL as focusing lens, the process was so critic that for defocus it, was enough almost just look the lens bad, not speaking about moving it .....Attachments
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Any tips? I noticed that the dot seems almost unchanged at whatever distance the final long FL lens is, except for a certain spot where it starts getting slightly smaller, and then larger again. I was turning in half-turn increments at the time, hard to make adjustments w/o the right tools :-/
What kind of divergence, in general, are people getting with their greens?
HIMNL9
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^ it still depend from the expander and front lens ..... and, ofcourse, from the initial diameter.
Smaller beams at the start, means a short-distance expander, and usually a bad divergence, where instead larger beams at the start (and, usually, longer modules), means better final divergences.
Smaller beams at the start, means a short-distance expander, and usually a bad divergence, where instead larger beams at the start (and, usually, longer modules), means better final divergences.
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I see. So there really is only so much I can focus it down to anyways, and it's much bigger than I had expected. If that is a beam expander, it doesn't seem to expand the beam by much, as it looks less than a mm at the aperture. Looks about 4cm at about 10m.
What increment turns do you suggest I try? is 1/4 turn fine enough to find optimum focus?
What increment turns do you suggest I try? is 1/4 turn fine enough to find optimum focus?
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What are you trying to focus, an already-made module ?
Anyway, the better solution (i'm assuming that you have a lens holder with slots on the border ring, for move it), is to get a piece of tube of the right diameter, then to file it in the way to left two small "pins" on the border, corresponding to the slots ..... so you can focus the module when it's turned on, passing the beam through the tube and seeing directly the results in real-time.
Anyway, the better solution (i'm assuming that you have a lens holder with slots on the border ring, for move it), is to get a piece of tube of the right diameter, then to file it in the way to left two small "pins" on the border, corresponding to the slots ..... so you can focus the module when it's turned on, passing the beam through the tube and seeing directly the results in real-time.
