safety glasses/goggles?

[JStewart]

Hi Adam,

Almost correct.

As the laser is not visible, you can’t rely on the aversion response to protect your eye, so you have to use the CW exposure limit (Class 1 AEL), instead.

OD = - log (0.39mW/2W) = 3.71 ~ OD4

But, that assumes that you are being exposed to a beam that is contained within a 7mm diameter. This may well not be the case with an 808nm pump diode. What you need to therefore check is what the profile of the beam is, then work out your maximum irradiance.

You can then use that same equation but instead:

OD based on irradiance = - log (10W.m^2 / actual irradiance)

10W.m^2 = CW MPE for visible / near IR beams.

Having a bit more time this morning I’ve added some more text to the note I wrote previously in this thread.

HTH

James

[cipher0]

didnt get a response from Stanwax yet

[TechJunkie]

May sound extremely silly, but if your phone shows a decent video stream, IE not choppy, then take the dark lens out of these.... ...and tape your phone to the open end. Instant multi-wavlenth viewing, at any power. And you can actually see the beam/s you're looking at.

[laserlackey]

$100.?? Uh, wanna take a guess how much glass-eyeballs cost? Tip: Spend a few-hundred bux.. Glass vs plastic... Here's a good 'low power-level' model: http://www.lasersafety.com/laser-saf...ses/r10/T5B02/

I got a pair of these when doing an assembly and tuning job recently. They fit very nicely, and I feel quite safe wearing them. $120 is what I paid, but it's worth it. Also, I'd get goggles that are coated to your specific wavelength. Obviously, if you're using them in a mixed-wavelength environment you'll need broadband coated lenses. Just keep in mind that you want as much protection as you can possibly afford. Spend money on good goggles and hope you never need them instead of buying cheap goggles and wishing you hadn't.

[cipher0]

May sound extremely silly, but if your phone shows a decent video stream, IE not choppy, then take the dark lens out of these.... ...and tape your phone to the open end. Instant multi-wavlenth viewing, at any power. And you can actually see the beam/s you're looking at.

Hey TJ.
Not saying it sounds extremely silly, but i think it wont work.
I've been told several times to keep my phone away from laser projectors as it can damage them.
Also youre going to get a headache trying to focus your eyes to see anything on your phone screen at that distance.
(And maybe 1W can burn the tape, dunno)

I got a pair of these when doing an assembly and tuning job recently. They fit very nicely, and I feel quite safe wearing them. $120 is what I paid, but it's worth it.

Thanks laserlackey. One question: have you tested them? (not saying if youve actually looked directly at a laser beam obviously ).

[TechJunkie]

You'd have to take a direct focused hit in the lens to bun the CCD chip, and then its only a small squiggle line. It can happen, but chances are slim. People taking out cameras with lasers is more of a myth. It will over load the CCD, but they bounce back. I saw a guy hit a camera with a 1W green lab laser, and it didnt damage a thing.

I know someone who did it with phone, and it worked fine. His only complaint was it was a liitle choppy. That was over 3 years ago, and phones have come a long way since them. If you dont want to use your own phone the are millions of used camera phones you can buy for ~$20. The Chinese sell small camera and monitor packages cheap, you can use one of those.

Its not as far fetched an idea as you would think.

[Galvonaut]

I'm not sure that phone and camera damage is a myth. There is an element of chance but anything around the 500mW mark is pretty good at destroying sensors.

A friend has destroyed 3 mobile phone cameras with laser thermal damage - they did not bounce back.

I have been warned that Canon cameras are particularly susceptible to laser damage (I shoot with a canon) so I am very careful!

Keith

You'd have to take a direct focused hit in the lens to bun the CCD chip, and then its only a small squiggle line. It can happen, but chances are slim. People taking out cameras with lasers is more of a myth. It will over load the CCD, but they bounce back. I saw a guy hit a camera with a 1W green lab laser, and it didnt damage a thing.

I know someone who did it with phone, and it worked fine. His only complaint was it was a liitle choppy. That was over 3 years ago, and phones have come a long way since them. If you dont want to use your own phone the are millions of used camera phones you can buy for ~$20. The Chinese sell small camera and monitor packages cheap, you can use one of those.

Its not as far fetched an idea as you would think.

[swamidog]

it's not a myth.

lasers (even low power) are excellent at destroying cameras. go take a look at a lot of the pics posted on LPF, you'll see plenty of sensor damage.

I'm not sure that phone and camera damage is a myth. There is an element of chance but anything around the 500mW mark is pretty good at destroying sensors.

A friend has destroyed 3 mobile phone cameras with laser thermal damage - they did not bounce back.

I have been warned that Canon cameras are particularly susceptible to laser damage (I shoot with a canon) so I am very careful!

Keith

[TechJunkie]

Those damaged cameras on LPF were from high power lasers focused to burn. Not a beam thats focused for a 30 foot shot. And they were small lines, not wiped CCDs.

We had this debate with http://www.youtube.com/user/Photonvids/, I'm sure you know this guy. He hit his camera with 2Ws of green a few times and showed it did nothing but produce 3 small dots. It wasnt till after he held the laser on the camera for a few minutes did it start to destroy the CCD, and finally kill the sensor. The myth goes you can use a pointer to destroy a camera. I guess if you had a 1W+ pointer, and held it still enough, and was sitting within 5 feet of it, you could. But pointing an average pen pointer at a camera 10 or 20 feet away is not going to do much.

You guys are missing the point, use an old, or cheap camera, or phone. You can pick up used digital cameras now for $5. Buy 10, LOL. Whats even more cool is you can record what you are doing. I'm sorry I didnt say "but not your Iphone5" but I thought that sort of went without saying, LMAO.

EDIT: I do have one question though. How do you line beams up with goggles that block the beam???

[The_Doctor]

Those damaged cameras on LPF were from high power lasers focused to burn. Not a beam thats focused for a 30 foot shot.

Bear in mind that if a camera is focussed for more than a very few feet, the long-shot collimated beam is more likely to get focused onto the CCD. A focussed beam might be more likely to diverge inside the camera. Doesn't explain a lot though, because a lot else will apply, like the amount of area above damage threshold.

About lining up beams, I'd use low power and thin glycol fog. Glycol will evaporate off the optics even if it ever gets there, with no harm so long as it didn't get there and get burned while it sat there. Can't beat a bit of fog and natural stereo vision for seeing where stray beams are going.

EDIT:
And if the beams are IR then there's always that IR sniffer I mentioned. Maybe cheap webcams are easier to get these days, but not as reliable.