Help with laser safety with RGB @ 1.6w

[slyoung1987]

Hi everyone, I’m Simon. I've been a member here for a while but this is my first post.

I've just bought a 1600mW RGB laser from Lanta lighting, and I've had it setup up outside testing it, it seems to be very bright and not nice if it catches you in the eye. I was wondering if there is a rule of thumb for distance you have to be away from the laser vs its power? Or at these powers do you never have them scanning onto a crowd of people?

Here are its specs:

Laser Diodes: 300mW Red (635nm) 300mW Green (532nm) 1000mW Blue (450nm) Mixed 1600mW White
Deflection angle: ±30°
Laser Class: 3b
Scanner: 25k High Speed Optical


I have a smaller RGB laser that’s a LK-PD2 that’s pretty nice indoors and isn’t too bad to the eye when scanning about. This new one is more for outdoors use, hence why I thought I’d get a bit more power on this new system.

I’ve seen you can by safety lenses for them that look quite cool, but I’m meant to be using it this laser this weekend outdoors so haven’t got time to order one and I’d have to find a way of mounting the mount as well… Is there any other cheap bodge way to defuse the light a bit?

Any help or tips would be greatly appreciated.

Thanks, Simon

[andy_con]

If you want to go out and do proper shows then Google laser visuals

James there runs a very good course on safety and how to do things properly

[WookieBoy]

Keep your beams out of the crowd and you'll be much safer!

There is no 'rule of thumb'. Audience scanning kind of requires lots of maths and an accurate lpm do be safe.

Andy's recommendation to do LVR's safety course is s good one.
However, seeing as I know the cost of LANTA kit, the course will probably cost more than your laser... but a lot less than litigation cos you permanently damaged someone's eyes!

[White-Light]

I've just bought a 1600mW RGB laser from Lanta lighting, and I've had it setup up outside testing it, it seems to be very bright and not nice if it catches you in the eye. I was wondering if there is a rule of thumb for distance you have to be away from the laser vs its power? Or at these powers do you never have them scanning onto a crowd of people?

Hi Simon,

It sounds as if you've had it in the eye whilst playing with it.

If this was from very close distance, then I suggest you consider a visit to an eye casualty dept. or optician for a check without undue delay and inform them you've been exposed. 1.6W can do serious damage and the nominal safe distance will depend on the specs but runs into the high tens of metres. ((I chose against putting up an example using an online calculator as it may encourage others to assume that distance as gospel or applying to all). It also by necessity, involved assumptions). If you're lucky you have got away with the exposure, many do, but it's Russian Roulette and the only way to know is to have a check. Not trying to frighten you, but be careful especially when working close up.

Heed Andy's / Wookie's advice. Audience scanning is potentially dangerous unless done properly and can leave you open to all manner of liabilities.

[mccarrot]

1. Never audience scan in small area's/ venues.
2. the longer the distance to audience the better, every meter the irridiance goes down exponential, example: a 5W laser @ 30 meter is much safer than a 500mW laser @ 5 meter.

In your case I would not audience scan at a distance anything closer than 20 meters. this is probably still way above MPE but risk at this distance is small.

[dwbothner]

NoIR offers RGB alignment eyewear for use with systems like this (although at these power levels, the filters allowing visibility of the beams are not affording full protection and great care should be taken or the powers should be be tuned down while aligning).
http://www.lasershields.com

[slyoung1987]

Thanks everyone for your info, I’m going to set it up in an area and tell people not to enter this zone and I’ll have it set up high on a T-bar stand with the laser pointed up into the trees. It has a multi pattern lens filter, so when in that mode it will probably go into the crowd a bit but this will only be the low end of the patterns spread where the lasers power is at its weakest so should be safe.

I tested my laser in a warehouse today at 20+ meters and the laser didn’t seem bad when it caught my eye at that distance, the beams diameter on the wall was at lot wider. I noticed that the 635nm red diode had the worst divergence out of all! Of course the green will be the best but I thought the red would have been better than the blue. On my other RGB laser the 637nm red is nearly as sharp as the green, I thought the 635nm was meant to have even better divergence then the 637nm?
Sorry if I’m getting this all wrong as I’m still quite new to this.

Thanks Simon.

[White-Light]

A couple of further points:

1. If your outside, pointing it upwards could land you in trouble with the CAA unless you have prior clearance or totally terminated beams ie nothing can shine though the branches = equals forest rather than tree! Even then risky.

2. You mention a filter. Is this a starfield type laser? If so it's potentially a whole different kettle of fish and potentially much safer. If so what does the Class Label say (although these can't always be relied upon).

[JStewart]

Hmm, another "Class 3B" laser outputting 1.6W.

It's not right to say that the risk at 20m is small. At 20m for a 0.25s momentary stationary beam exposure, if the laser is producing the output claimed by the manufacturer, the safety limit is exceeded ~150 times. Even with a finger beam type effect, it will most likely be in the order of 40 times the safety limit.

A safety lens will improve things, and can get the safe exposure distance down to something that would be more compatible with the intended use of the projector. But in any event, if you are planning on using what is a Class 4 to directly expose the audience to beams, using a power meter so you can properly assess what the levels at the audience are is essential.

As others have said, if there is any doubt, just keep the beams all overhead. Laser light is is quite different to other types of stage/performance lighting. We recently compared a Sharpy with a below-MPE laser exposure, and the results were quite startling. http://www.lvroptical.com/blog-sharpy-lasers.htm

James