Results 1 to 8 of 8

Thread: Passing Deep Blue & Violet

  1. #1
    Join Date
    Mar 2007
    Location
    Ontario, Canada
    Posts
    31

    Default Passing Deep Blue & Violet

    I have seen a couple argon laser shows obtaining green, blue, violet and all together cyan. Read somewhere on sams laser FAQ that you can get a dichro to pass the deep blue and violet lines 476.5 and 457.9. Does anybody know where I could obtain one of these? It is a possibility they could have been using a PCAOM, but having not seen more then one at once I assumed not.

    Thanks
    Brian

  2. #2
    Join Date
    Jan 2006
    Location
    Charleston, SC
    Posts
    2,147,488,218

    Smile

    If it was an argon show they were almost certainly using a PCAOM to select those lines. If they were using separate dichros to do it, the beamtable would be needlessly complicated. (Lots of extra optical elements that would have to be physically switched in and out of the beam path - ugh!) PCAOM's are very common, they switch super fast, and a decent 6 or 8 channel unit can easily accomodate all the major argon lines.

    However, if you're thinking about adding some 405 nm light from a Blue-ray diode to your solid-state projector, then yeah, you'd need a dichro with special coatings. Don't know if you can special order dichros like that from someone as mundane as Edmunds, or if you'd need to go to a direct supplier. (Yadda can probably chime in here with some suggestions as to where to order them.)

    Adam

  3. #3
    Join Date
    Jun 2005
    Location
    SoCal
    Posts
    490

    Default

    http://www.edmundoptics.com/onlineca...productid=2460

    For what you describe, you're looking for shortpass filters, a bandpass will
    follow a curve... if you know the exact frequency to block/pass you can use
    an interference filter.

    I assume if there is no "blending" then there isn't a PCAOM, they may
    also be using prisms (2 to 4 depending on the technque) as that was
    how color selection was handled a long while back... (Look up prism
    compressor, or I can describe it in more detail if you're interested) I also
    recall there was a thread on PL about using prisms as well...

    The actual technique you can tell by the speed, if color is blazingly fast
    then even if they're using primaries, they could easily attach an 8-channel
    PCAOM for each line... If you see 3 sets of argon colors, you could be
    seeing galvo blanking, (there's no limit, but due to the cost of galvos,
    people keep the number down) if you are seeing color changes "subframe"
    but it doesn't seem too fast, then it could a prism on a galvo or a GM20
    with a pinhole... if it's slow then it's probably dichros on a GM20...

    If you know the name of the laserist/company we can also make educated guesses
    based on what they specialize in...

    [edited to add]
    PCAOM is fastest, a lot of people who specialize in beamshows actually
    don't like PCAOMs though... You can tell by analog modulation.

    Scanner blanking is also fast, This is actually my favorite method due to
    it's color efficiency, but alignment woes and cost keep this relatively rare
    in today's cheap PCAOM world. These can be analog or on/off depending
    on the skill/patience of the system builder.

    Prism galvo is slow, but fast enough to see subframe colors. You will
    only see full color primaries

    GM20 style actuators is slow, but thin "beamblock" flags can let it be reasonable.

    The slowest is actuators with actual dichros glued on...

    Last you'll also find people with non-standard techniques like dichrowheels, etc.
    Last edited by yaddatrance; 04-04-2007 at 14:36.

  4. #4
    Join Date
    Oct 2005
    Location
    Melbourne, Australia
    Posts
    678
    Blog Entries
    1

    Default

    Quote Originally Posted by Buffo View Post
    If it was an argon show they were almost certainly using a PCAOM to select those lines. If they were using separate dichros to do it, the beamtable would be needlessly complicated. (Lots of extra optical elements that would have to be physically switched in and out of the beam path - ugh!)
    Adam
    Gross assumption ?

    You should have seen the beam table in our argon.
    Now proudly stocking and offering the best deals on laser-wave

    www.lasershowparts.com
    http://stores.ebay.com.au/Lasershow-Parts

  5. #5
    Join Date
    Jan 2006
    Location
    Charleston, SC
    Posts
    2,147,488,218

    Cool

    Hi aijii;

    Yeah, well, I assumed he was speaking of a recent show, not something from 10 years ago.

    Or ro you mean to tell me you're STILL using dichros and a galvo-powered color box to select colors? (Surely not!)

    I mean, damn... Even Clandestiny had a PCAOM in his beamtable that he brought to FLEM, and he was running the old GM-20's in there! And to think that he brought it because he wanted to show us what an "old school" beamshow rig looked like.

    Damn - upgrade or die dude! (Just kidding!)

    In all seriousness though, you're right. There is a lot of older equipment out there that still uses dichros and/or prisms for color selection. But you gotta admit that a PCAOM is the way to go. It's not that much more expensive, and it get's rid of a lot of extra moving parts. (Plus it's faster!)

    Then too, of the handfull of professional laser shows I've either attended or helped out with in the last few years, color selection for the ion lasers has always been done with a PCAOM. I honestly didn't think anyone was still using the older technology anymore.

    Adam

  6. #6
    Join Date
    Oct 2005
    Location
    Melbourne, Australia
    Posts
    678
    Blog Entries
    1

    Default

    Well... our first argon projector, which we built a couple of years ago was a twin head dichro/actuator based beast...

    Basically we had a green dichro and a blue dichro on actuators for the main scan head. With these we could get cyan, blue, green, and a fainter blue when both dichro's were dropped.

    The "waste" beam from each of the dichros on the main head was sent over to the other side of hte beam table, realigned into one beam, and put into the slave scan head.

    We also had a shutter on each scan head, in addition to drop down linear diffraction and burst diffraction gratings on the main and slave heads respectively.

    Basically - we could simultaneously - green and blue, or blue and green, or cyan and a dimmer blue colour from both heads... all selectable via dmx from within LivePro.

    Looked cool when running a dmx chase.... daves got a video of it somewhere i think.

    Both scan heads ran off the same signal, but we could flip x and y via DMX as well on the slave head.

    It looked unbelievably good, compared to our previous all green dpss shows...

    But the box was too big and heavy, and the slave head used to come out of alignment whenever we sat it in it's truss cradle. It was an absolute cunt of a thing the morning after a show, so we fucked it off.....

    AND

    we are rebuilding it with a neos 4 channel pcaom, recombiner for the slave head, on a much smaller footprint base plate (105cm by 30cm!!!), with ease of transport (at 7am after an all nighter) in mind...

    Thats pretty small for 3.5 watts of argon.... just need to sort out closed loop water cooling and we're laughing.
    Now proudly stocking and offering the best deals on laser-wave

    www.lasershowparts.com
    http://stores.ebay.com.au/Lasershow-Parts

  7. #7
    Join Date
    Oct 2005
    Location
    Melbourne, Australia
    Posts
    678
    Blog Entries
    1

    Default

    http://www.oraclelaser.com.au/2004/p...ora/aurora.htm

    Our argon was set up similar to this - except each head could be green blue or cyan if we wanted to. The aurora beam tables are simpler (probably a good thing to be honest) - just one actuator to send blue to the slave head...
    Now proudly stocking and offering the best deals on laser-wave

    www.lasershowparts.com
    http://stores.ebay.com.au/Lasershow-Parts

  8. #8
    Join Date
    Mar 2007
    Location
    Ontario, Canada
    Posts
    31

    Default

    I can't seem to find the video anymore, nothing special just a rave, club, or basment party that only had an argon laser. But ther was definately no "bleeding" since it was several seconds of before each color switch. With only the three colors I wouldn't see the need for fast switching anyways and a PCAOM on argon just seems like a waste of power.

    Hmm, the galvo color selection seems like a very good idea, I assume its set up the same as galvo blanking and making it analog is just varying the amount of dichro in the beam much like you can do with MFE actuators and flags and the right drive card. And at $140 for a Pair of 10kpps galvos and drivers is still a bit cheaper then MFE or GM20s.

    Aijii, do you have any pictures of the inside of your projector? I'd like to see how you did that, My end goal is close to the same thing, dual crossing scan heads but just with a 50/50 not using the waste beam.

    -Brian

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •