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Thread: RGB laser, help please!!

  1. #1
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    Default RGB laser, help please!!

    Hi guys

    This is my first post, i will try to write as goog as i can coz i am from Chile, so i dont use english a lot

    I have built a 1.6 watt RGB laser with this diodes from China (just a small factory):

    650nm 800mw
    532nm 300mw
    447nm 500mw
    20k Scan set

    The laser is OK but the red is just not powerfull enough the red is just too deep and you cant see it a lot. I save some money and now i am ready to build a new one. This time i will use CNI diodes (is the best i can get here), but i need to know what will give me a good color mix. This is my first idea:

    650nm 2watts
    532nm 500mw
    457nm 1watt

    Is that a good idea, should i go with 635nm in red? (if i do i think that 1 watt will be ok). what about the blue, 457 or 447?


    Thanks for your time

  2. #2
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    Default

    If you read a lot of the threads in the projector forum, I think you will find a general preference for the 640nm diodes over the 650s, but... if you have it already, a diode in the hand is worth two on the internet. There's lots of good advice sprinkled throughout those old threads...

  3. #3
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    I have read some old threads but i dont know how to calculate the power in the 640 or 635nm range. I am used just to work on 650nm coz that is almost the only thing you can get around here.

    Now i can order direct from a CNI seller so i have more options

    In some threads i have seem some chroma test for the lasers, how do you do that. What program do you use. I normally just use CNI reference table

    Thanks for the help, i am new on this

  4. #4
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    Quote Originally Posted by FULLPRODUCCIONES View Post
    In some threads i have seem so䍣牨浯彡歰⹧硥me chroma test for the lasers, how do you do that. What program do you use. I normally just use CNI reference table
    Chroma - A Laser Color Blender (link to thread)
    Dowload Chroma

    Enter in your wavelengths, and their powers in watts, calculate.

    As for reds the 635nm lasers use a huge square beam. The 640's have less power but have a nicer beam, and the eye has a higher sensitivity to this wavelength than the 650.

    -Adam
    Last edited by sugeek; 01-01-2011 at 13:18.
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    Laser (the acronym derived from Light Amplification by Stimulated Emissions of Radiation) is a spectacular manifestation of this process. It is a source which emits a kind of light of unrivaled purity and intensity not found in any of the previously known sources of radiation. - Lasers & Non-Linear Optics, B.B. Laud.

  5. #5
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    Thanks this will help a lot

  6. #6
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    640nm Red. No contest as its both more visible by factor of around 1.5x and also has better beam specs which means less internal losses on the mirrors than eg 635

    I'd also consider 457nm Blue - a lot more expensive but a bit more visible.

  7. #7
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    Just to give you an idea of what 640 is like, I tested 380mW of 640 against 1.1 watt of 650 and they were just about the same to the eye. However, the 640 has vastly better beam specs for combining with 532 and 445.

  8. #8
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    Quote Originally Posted by White-Light View Post
    I'd also consider 457nm Blue - a lot more expensive but a bit more visible.
    Given the fact that you can get an insane amount of 445nm power for the price you pay for a 457nm blue, the 445 would win by far. (even with corrective optics)

    Sure, the 457 has better beam specs, but for most practical shows this won't make a lot of difference. It's only better for people who are quite the purist and feel lasers should go by the numbers -- the guys who swear by Chroma and a ruler to measure their beams.

    Furthermore, the 445nm is a direct diode laser, which will modulate a lot better than a 457nm DPSS.

  9. #9
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    I agree.. DPSS reliability/stability, size, cost and modulation issues aside, a well corrected 1W 445nm diode laser will have a 3.5mm beam and under 1mR divergence and provide more than enough blue to work well with the intended 500mW of 532nm.

    From your experience White-Light, why do you recommend a laser costing so much more?
    A little bit werrrr, a little bit weyyyyyy, a little bit arrrrgggghhh

  10. #10
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    I wasn't making a recommendation based on value for money which is why I was 1st to point out that its a far more expensive option. If you want value for money 445 wins hands down.

    It also has nothing to do with Chroma which I still rate Stoney provided its used properly ie by looking at the white triangle instead of the white spot in the centre, taken in that context I believe its highly accurate. In the past others and myself (before I saw the light) were obsessed with the very obvious central white spot which meant that real life and the programme cleary didn't match up in terms of white balance prediction. However, Steve Milani's latest projector's spec combined with the wider white triangle shows that predictions are far more accurate than was previously thought as his projector shows a cold blue icy white which taken on the spot method was clearly outside of the white balance area but taken using the white triangle method is clearly within the white area and within the area you'd expect to find it for an icy blue colour. So yes I do believe its accurate and has had unfair press from memebers on here who like me, interpreted the graph wrongly in the 1st place based on the obvious white spot instead of the less obvious white triangle. You can't blame a programme for user error!

    However, explanation over, I don't make a recommendation here based on Chroma.

    The reason I'd take 457 over 445 money allowing is:

    1. 445nm makes a nice white but I still believe it pulls other colour mixes down in brightness causing reduced luminosity of the projector overall. I still like 445 as an individual colour but I don't like projectors with it in as much eg 473 because of the dulling effect it appears to have on many mixed colours.

    2. 457 is that little bit brighter than 445nm watt for watt

    However, its personal. I haven't seen 457nm in action myself although clearly its heading in the right direction from the wavelength point of view for brightness. I have heard from others though that its still a deep blue whilst offering the greater luminosity. McCarrot would really be the best person to comment here as I believe he both sells and uses 457nm.

    I would personally choose it over 445nm myself anyday given the luminosity downside to 445nm which I quite frankly detest. In fact money allowing I'd take 473 over 445 for colour anyday, simply because I'd rather compromise depth of blue than projector luminosity and thus impact.

    I've never heard anyone in a club say that blue isn't dark enough. I have heard people say though I wish the lasers were brighter. Horses for courses.

    I know most would recommend 445nm as it has a large following especially given its price drop and thats fine. I'm in a minority who do not like it. If the OP wants value for money then 445 is the way to go.
    Last edited by White-Light; 01-02-2011 at 03:37.

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