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Thread: AR coated projector window question

  1. #1
    Join Date
    Oct 2009
    Location
    Perth Western Australia
    Posts
    844

    Question AR coated projector window question

    Hi Guys,
    I'm about to buy an AR coated window for my projector build.

    The windows I'm looking at are in the link below.
    http://www.edmundoptics.com/onlineca...w=21&PageNum=2

    The two windows I'm considering are both 4inch x4inch. The only difference is, one is 1mm thick and the other is 3mm thick.

    The lasers I'm going to buy are;
    642nm red
    532nm green
    445nm blue

    Scan angle is 54deg max

    I think I'd like to go for the 1mm but I fear a window if this size might be a bit too fragile.

    If I decide to play it safe and get the 3mm window, would there be any added artifacts when scanning through 3mm of AR coated glass(both sides) compared to 1mm.

    I imagine any such problems would only be noticeable at wider scan angles.

    Am I worrying about nothing or is this something that would cause problems when doing graphics?

    Anyones thoughts on this would be appreciated.

    Thanks
    Kit

  2. #2
    Join Date
    Nov 2005
    Location
    Melbourne, Australia
    Posts
    3,691

    Default

    Hey Kit,

    I reckon you are worrying about nothing there. I have never had any issues with ar glass, and actually the only issues I have with standard glass is a bit of loss.

    We used the Edmund stuff in our yags, and dammed if I can even see the glass!





    Quote Originally Posted by kitatit View Post
    Hi Guys,
    I'm about to buy an AR coated window for my projector build.

    The windows I'm looking at are in the link below.
    http://www.edmundoptics.com/onlineca...w=21&PageNum=2

    The two windows I'm considering are both 4inch x4inch. The only difference is, one is 1mm thick and the other is 3mm thick.

    The lasers I'm going to buy are;
    642nm red
    532nm green
    445nm blue

    Scan angle is 54deg max

    I think I'd like to go for the 1mm but I fear a window if this size might be a bit too fragile.

    If I decide to play it safe and get the 3mm window, would there be any added artifacts when scanning through 3mm of AR coated glass(both sides) compared to 1mm.

    I imagine any such problems would only be noticeable at wider scan angles.

    Am I worrying about nothing or is this something that would cause problems when doing graphics?

    Anyones thoughts on this would be appreciated.

    Thanks
    Kit
    Last edited by dave; 05-27-2010 at 01:00.
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  3. #3
    Join Date
    Mar 2008
    Location
    Crawley (UK)
    Posts
    449

    Default

    We do sell 1 & 2mm if that helps

  4. #4

    Default

    Quote Originally Posted by pelosh View Post
    We do sell 1 & 2mm if that helps
    ah your still alive martin, we didnt see you at the meet?

    you got a price for the glass?
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

  5. #5
    Join Date
    Mar 2008
    Location
    Crawley (UK)
    Posts
    449

    Default

    Yeh, I was bit busy with lasers but somewhere else...

    http://www.synchrovision.co.uk/produ...ive-window-ARW

  6. #6

    Default

    I'd recommend the 3mm thick window at that size. Just for mechanical reasons. The only optical reason would be flatness, and the thicker one will probably have flatter surfaces too. Doesn't Edmund have plots for their coatings? There might be a better AR coating at that average angle.

  7. #7
    Join Date
    Dec 2007
    Location
    Nottingham, UK
    Posts
    2,757

    Default

    I bought a 3" disc of that a while back. Top stuff. You won't find anything cheaper with higher transmittance.
    I ended up going for the 1mm in the end, only cos the 3mm was out of stock in that size for a while...
    If I chose again, 3mm sounds a better choice
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  8. #8
    Join Date
    Nov 2007
    Location
    SoCal / San Salvador / NY
    Posts
    4,017

    Default

    Hey Kit...

    Sorry for not gettin back to ya on the emails, there, m8 - been pretty slammed, as-usual but next week opens-up a bit for me, so I'll get back atcha...

    I also heartily recommend the 'CDAR' - the stuff is pretty-well 'invisible', and yes, 3mm would be 'safer' for any chance-knocks... And like Sir Dave said (...whatup Dave? , no worries on 'abberation' from thickness...

    ...One thing we have always done is mount is at a slight (like 10˚ or less, is fine) angle, base-to-top, this way, whatever minute R will not be retro'd back into your galvos, but, rather, up into the 'ceiling' of your box... ie:

    Click image for larger version. 

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    ...and the R % is so slight, that worry over 'eye-safety' from the angled-window shooting 'up' when your box is open, is pretty-nil... 'regular' float-glass is at least 10% R, so there you have more 'worry' over 'back-R'... especially when your window is on a 40W puppy! (10% of 40W is just a tad much to 'ignore'...

    ...One bloke reported that the 'CDAR' does not do so-well for those with the 405s in their rig, but it does not appear you will have that 'worry' since you are running 445...

    on the CDAR and chat with ya soon, m8...
    cheers..
    j
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

  9. #9
    Join Date
    Oct 2009
    Location
    Perth Western Australia
    Posts
    844

    Cool

    Hi guys

    Thanks a heap everyone for your ideas and explanations

    It's settled, 3mm it is.

    Jon, I never would have thought of tilting the window like that. It makes real sense.
    Stay tuned for some tilted window SolidWorks projector models being posted soon.

    Ah, once again, I've come to the right place.

    Is there nothing PL can't do?

    Thanks
    Kit

  10. #10
    Join Date
    Dec 2009
    Location
    Seattle, Wa
    Posts
    413

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    Hey Jon and Kit,

    What's the reason for tilting the glass to prevent it from reflecting back in the galvos? Does this protect the equipment somehow or produce a better beam?

    Also wondering, how do you guys typically mount the glass? I was thinking about using glue but that might get messy if the glass ever needed to be replaced. It would be cool if someone sold some sort of clip and shutter assembly that had a clip to hold the glass on the inside and a metal safety shutter on the outside.

    See ya,
    Mike

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