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Thread: solution for varying laser scanner mirror and laser module heights

  1. #1
    Join Date
    Oct 2016
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    209

    Default solution for varying laser scanner mirror and laser module heights

    Do you add a riser plate to the scanner? Do you custom mill it to the exact height?
    Two bounce mirrors could work too but with 2 and at extreme angles there would be quite a loss. With one mirror you could direct the beam exactly to the middle of the first scanner mirror but then the second mirror wouldn't be able to scan at its full angle.

  2. #2
    Join Date
    Feb 2008
    Location
    East Sussex, England
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    5,246

    Default

    I've found the best solution is to have a final steering mirror for the RGB beam, to put the beam exactly where you want it on the scanner mirrors, and preferably at a higher height than the entry mirror on the scanners, so the beam comes 'down' into the first mirror.
    So in those circumstances, I have the scanner block as low as possible.
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    If you click the FB page link in my signature the most recent post shows the arrangement of the dichros and mirror on one of my 8W projectors. I keep as many things fixed as possible, so in this case the blue/red module is solidly mounted, the green 'can' be variable, either by shimming, or my adding a little Z fold and an additional mirror to get the height right. In this instance it wasn't necessary, but it was when I had the DPSS in there.
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    edit: I'll add a comment to that pic of the previous setup to show what I mean...

    I should add that in this scenario the performance was actually better than a 90 degree angle on the green dichro. This is because it performs better at narrower angles, so the addition of the extra bounce mirror isn't really a factor. That said, I don't really worry about dichro losses in these heady days of 1W+ diodes. Any actual losses are going to be imperceptible compared to when we were scrabbling around for every last mW with 100mW diodes.
    Last edited by norty303; 04-11-2017 at 03:51.
    Frikkin Lasers
    http://www.frikkinlasers.co.uk

    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

  3. #3
    Join Date
    Oct 2016
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    209

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    Thank you. Your design is pretty much what I have right now, there's a final bounce mirror since the modules are facing the side of the projector while the scanner is on the front-middle.

    But again the issue I see with steering with a bounce mirror is if you steer the beam to hit the first mirror just right that will cause the beam the offset on the second mirror hence clip the same diameter beam at lower angles, right? Or am I wrong about something here?

  4. #4
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,246

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    I'm afraid I don't really understand what you're describing.
    If you are worried that by not having a straight run into the first mirror, the reflected beam won't go straight up to next mirror then this is simply something g you adjust by rotating the galvo in the block.
    It's something you do on every setup, even if you 'think' they're straight.
    Frikkin Lasers
    http://www.frikkinlasers.co.uk

    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

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