I Upgraded my laser projector, but have a question

[jdavis7765]

So started here a bit ago and bought a EMMA laser on Aliexpress and upgraded the scanners to Compact 506's. Was not super happy with the beam quality, especially with the blue laser so I was initially just going to upgrade the lasers with a kvant RGB module, but ended up deciding it would be better to get a "legal" laser. So I opted for the Clubmax 2000 ILDA. Had a few issues with the scanner taking a crap but that is working fine after a covered repair thankfully!

My main question here is mostly to put my mind at ease, but the beam quality is not what I thought it would be spending 2,000 dollars on a laser but I may just be "pixel creeping" and just need validation either way about it. Most pattens display without issue, it is just the single points that its most noticible but again, it may just be me being a perfectionist.

I have included screenshots below comparing both lasers with Clubmax on the bottom and Emma Laser on top. All photos were taking at same shutter, apeture, and iso, except the white which I lowered the ISO speed a bit.

And for the record, while this was in for service for scanner issue, they said the beam quality was acceptable.

Attachment 58228

[buffo]

Were you using the same ILDA controller for both pictures? If so, then one thing you can try is to adjust the blanking offset when you have the controller connected to the ClubMax. Usually the default setting is 4 points for the blanking offset, but you may see better results with it set to 3 or 5. It's a long shot, but it's worth trying. If this doesn't help, then you are probably stuck with what you have.

Remember that the ClubMax projector is designed to be used primarily for beam shows. It uses multi-mode diodes to get higher power, but the trade-off is that the beam quality isn't as good. Yes, they do employ secondary correction optics, but even so, the beam quality is never going to be as good as what you can get from a lower power projector that uses all single-mode diodes.

Your original EMMA projector probably had low-power, single mode diodes in it, which is why the beam spots from that unit look so much sharper on the wall.

When you view the beams moving around in the air from your Clubmax, it's unlikely that you will notice the slight beam artifacts that you see on the wall in your picture.

Adam

[jdavis7765]

Were you using the same ILDA controller for both pictures? If so, then one thing you can try is to adjust the blanking offset when you have the controller connected to the ClubMax. Usually the default setting is 4 points for the blanking offset, but you may see better results with it set to 3 or 5. It's a long shot, but it's worth trying. If this doesn't help, then you are probably stuck with what you have.

Remember that the ClubMax projector is designed to be used primarily for beam shows. It uses multi-mode diodes to get higher power, but the trade-off is that the beam quality isn't as good. Yes, they do employ secondary correction optics, but even so, the beam quality is never going to be as good as what you can get from a lower power projector that uses all single-mode diodes.

Your original EMMA projector probably had low-power, single mode diodes in it, which is why the beam spots from that unit look so much sharper on the wall.

When you view the beams moving around in the air from your Clubmax, it's unlikely that you will notice the slight beam artifacts that you see on the wall in your picture.

Adam

Too funny I was writing a reply this morning but never hit it! I was actually looking to just delete the post because I found that blanking largely fixed it and didn't want to keep my embarassing newbie post up lol. I have no idea how/why I missed that but here I am. To answer your question, it was the same ILDA controller.

This may sound like a stupid question, but I understand what divergence is and also that the Clubmax has "Ultra-low-divergence" but that low divergence is not directly related to the quality/shape of the laser beam?

Thank you for the reply Buffo!!

[buffo]

I was actually looking to just delete the post because I found that blanking largely fixed it and didn't want to keep my embarassing newbie post up lol.

It's not embarrassing at all! Also, leaving the post active allows other people to learn from it, even years down the road.

I understand what divergence is and also that the Clubmax has "Ultra-low-divergence" but that low divergence is not directly related to the quality/shape of the laser beam?

"Ultra-low-divergence" is a marketing term; it's meaningless without the actual numbers to back up the claim. (And there is something funny going on with those numbers - see below.)

Higher power, multi-mode laser diodes typically have different divergence numbers for the X and Y axis. This is due to the rectangular shape of the diode emitter. The wide axis of the emitter will have a lower divergence than the narrow axis. To correct for this, you need secondary optics that are positioned after the primary collimating lens. The secondary optics are aligned with the narrow axis of the diode emitter, which is the axis that has the higher divergence, and they work to expand this narrow axis, which reduces the divergence.

When the beam is still very close to the diode, the beam profile on a multi-mode diode will match the orientation of the emitter. So if the emitter is oriented with the long axis in the vertical plane, the beam will look like a vertical line. But as the beam propagates, the higher divergence of that horizontal axis will make the beam expand much faster in the horizontal plane. Thus, within a few feet of the diode, the beam will now appear to be much wider than it is tall. The orientation is now opposite to that of the diode emitter.

To fix this problem, you position the secondary optics very close to the diode. (Basically right after the primary collimation lens.) The secondary optics will expand just the horizontal axis of the beam, making it wider, and then the beam is re-focused to be parallel again. If you set it up just right, you can widen the horizontal axis to match the width of the vertical axis, changing the beam profile to a perfect square. Also, since you have expanded the beam diameter in the horizontal axis, you will have also reduced the divergence in the horizontal axis. Ideally you want the divergence of both axis to be the same, while also having a perfectly square beam profile. In practice though, this isn't always achieved.

All that being said, I've seen the ClubMax 2000 in person, and the beam quality isn't all that bad. It's not as good as the output from a single-mode projector, but it's not horrible either. (You also need to remember that the ClubMax is designed for beam shows, not graphics shows, so beam quality isn't as much of an issue.)

Looking at the ClubMax website, it appears that they are claiming .58 mrad divergence, which initially makes no sense, as it's clear that the beam is nowhere near that tight. But upon further reading, I see that they are averaging the divergence of the fast axis with the divergence of the slow axis, which of course will give you an artificially low value. It would be more honest to just list the individual divergence numbers for each axis.

Adam