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Laser safety


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  • Laser safety

    I've worked with a band that has a couple of them cheap red and green laser effects that you could get at GC. I just got in a couple $15 Chinese ones that do this:

    I seem to remember that the GC ones did more patterns but they were close to $100 each I think. Anyways the Chinese ones are labeled as class IIIb and maybe require a variance to legally use? The ad I bought them from said that both lasers are 50mw although the "manual" that came with them says the red is 100mw and the green is 50mw. The beams are always split many ways so I doubt any one beam is over 1mw. They seem to work OK - the green is much brighter to my eye than the red but I think that's because of the way our eyes respond to different wavelengths. Whatcha think about all that? 

  • #2

    A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as those from paper or other matte surfaces are not harmful. The AEL for continuous lasers in the wavelength range from 315 nm to far infrared is 0.5 W. For pulsed lasers between 400 and 700 nm, the limit is 30 mJ. Other limits apply to other wavelengths and to ultrashort pulsed lasers. Protective eyewear is typically required where direct viewing of a class 3B laser beam may occur. Class-3B lasers must be equipped with a key switch and a safety interlock. Class 3B lasers are used inside CD and DVD writers, although the writer unit itself is class 1 because the laser light cannot leave the unit.

    Bill Cronheim
    Entertainment Systems Corporation
    Back stage since 1965
    Equipment specialist since 1973


    • RoadRanger
      RoadRanger commented
      Editing a comment

      Further research shows these are normally sold here as a class IIIr device as the beam splitting reduces the internal class IIIb lasers to that level externally. But a Chauvet manual still says you shouldn't direct them towards audience members as it's illegal . An American DJ manual says the same: http://www.americandj.com/pdffiles/micro_galaxian_(reset).pdf

      Thing is they publish videos like this showing illegal operation:

      WTF  ?