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FrozenGate by Avery

Expanding Lens Off Centre

W

walcen

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Feb 18, 2014
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Hi guys, I purchased some green laser modules from Dx and they seem to be reasonably well made for the price, they work well too and the lenses seem to be made of glass but I notice that the Expanding Lens is Off Centre. :wtf:

Is this normal? Or is it compensating for a poorly installed diode or crystal?

And would it affect the trajectory of the beam over a long distance in relation to the housing?

Sorry for the crazy question but I look at every thing from an engineering point of view.
Please excuse the poor quality of my photo.

regards

Walt
 

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It is probably a factor of poor QC. Most of the green modules I have the beam exits at a slight angle. Its just the nature of the cheap DPSS modules.
 
You get what you pay for. I was lucky in that out of the last 3 modules I have bought, only one was not working (crystal set wasn't aligned at all) and one had a beam that came out at an angle. But hey, only cost me 5$, so whatever. If the off center beam is really a big issue to you, just pop that sucker off, and re-glue it. Super glue will hold it in place fine.
 
crazyspaz said:
YIf the off centre beam is really a big issue to you, just pop that sucker off, and re-glue it. Super glue will hold it in place fine.
Click to expand...

Thanks for the reply Actually you can't just pop the sucker off and relocate it because whist it's off centre it works fine, I tried what you suggested and it through the beam all over the place so I put it back. It doesn't bother me at all, it's just a learning question.

regards

Walt
 
Huh, weird. Glad its OK though. For future reference, you can get 532 modules at fasttech.com for ~5$--save you a bunch of money over ebay sellers.
 
its probably cheaply assembled, but be aware virtually no DPSS is straight, and its quite likely it was put there for a reason. most of my lenses are offset somewhat too, to help keep the beam straight, but that's not always the case. best judgement is required here.
 
ultimatekaiser said:
its probably cheaply assembled, but be aware virtually no DPSS is straight, and its quite likely it was put there for a reason. most of my lenses are offset somewhat too, to help keep the beam straight, but that's not always the case. best judgement is required here.
Click to expand...

So does that mean that the beams don't run parallel to the housings or does the focus lens correct it?

This could be an issue for bore or laser sights with elevation and windage, one could set the dot at a given distance but anything before or after that distance will be out.
 
walcen said:
So does that mean that the beams don't run parallel to the housings or does the focus lens correct it?

This could be an issue for bore or laser sights with elevation and windage, one could set the dot at a given distance but anything before or after that distance will be out.
Click to expand...

Very few DPSS lasers have straight beams without expensive correction. A crooked beam is normal. If it's not hitting the side of the aperture LEAVE IT ALONE - there is no need to mess with it. It could be off center or rotated on purpose to use the concave surface for correcting the beam angle. Many of my lab modules are like that too. See some of my dpss posts, almost none of them are straight, and the few that are even remotely close are because I did a professional re-alignment/adjustment myself.

As for glue, use a very small dab of white rubber soft RTV or epoxy. Superglue/cyanoacrylate a will attack the glass coatings and spread thin and mist the lens.
 
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cheech226 said:
DON'T use super glue! it will flow over the lens and ruin it. been there, done that one.
Click to expand...

it wont if you use a small dab...I have used super glue on different lenses several times with no problems. Definitely not the best way, but if you're careful its fine...
 
crazyspaz said:
it wont if you use a small dab...I have used super glue on different lenses several times with no problems. Definitely not the best way, but if you're careful its fine...
Click to expand...

super glue should never be used on high quality optics. period. its destructive, and it expands as it dries. if you surround a lens it can put stress on it and cause it to shift or crack. (personal experience with this)
 
They are glued off centre because the beam comming out of the cristal is not absolutely in centre. So the lens is correcting this by being glued a bit off centre so the beam gets almost centered and hits the collimating lens.

So nothing to worry about.
 
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ultimatekaiser said:
super glue should never be used on high quality optics. period. its destructive, and it expands as it dries. if you surround a lens it can put stress on it and cause it to shift or crack. (personal experience with this)
Click to expand...

Yea I get that, I was just saying a little dab for this purpose would be fine...not exactly super expensive optics on 5$ a 532 module :p
 
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