Safe?

[Anthony506]

Hey all, I just got a new 300mW DIY kit laser and put it together.

Quick question before i go and start using my laser while other people are watching, will the light given off objects eg. match head, be dangerous to the un-protected eyes? I had a quick look at it without goggles and its very bright, can barley look at it. I know that direct/reflected light of shiny surfaces would definitely cause permanent damage just wasn't sure about other surfaces such as match heads.

Just thought before i put everyone's eyes at risk I'd ask some professionals .

Thank you :thanks: ,
Anthony

 

[Grix]

Someone correct me if I'm wrong, but I think I remember that you gotta have at least 1000mW for diffuse reflections to be dangerous.

 

[Tech_Junkie]

I caught a 20mw 532nm reflection in my right eye and have a small black dot in the upper right corner. I dont think I imagined it.

 

[Jaseth]

"A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as from paper or other matte surfaces are not harmful. Continuous lasers in the wavelength range from 315 nm to far infrared are limited to 0.5 W."

Basically this means diffuse reflections are not dangerous unless the laser is 500mW+
However, personally I use goggles for viewing any 50mW+ dot closer than 5 feet or so. Obviously the diffuse reflections are enough to cause damage if your eyes are very close to the surface the dot is on, the question is just how close that can be. Since I treasure my eyesight, I decided that I would use a fairly large distance as minimum.

Even if you could safely be a lot closer to the dot when it's on a matte surface, I still find the dot uncomfortable to view up close.

One thing you have to watch out for is matte surfaces which may become shiny, such as black plastic which can quickly melt enough under laser light to create a flat and highly reflective surface.

Seb

 

[Anthony506]

Alright, thanks alot guys! :wave:

 

[LSRFAQ]

Its cumulative as well, so a for a typical case,

Argon eye surgery laser, aimed at a wall:

3 meter viewing distance, 300 mW of blue, one workday of exposure, good diffuse surface, 320 uWatt per cm^2 OSHA limit, 8 hours.

In reality, if you stood there looking at 300 mW of blue for 8 hours, you'd have one heck of a migraine, eye fatigue and after images.

If you did it for more then a few days, you'd see your blue response fall off till you stopped working with it for a few months...

Its a proven hazard for eye doctors, loss of blue response.. Green is similar..

So just because its safe, doesn't mean its not painful or does not have long term consequences...

Steve