Laser Goggles Replacement?

[1Nick]

well, i ordered a 200mw red laser (it should be here in a week or so) and people recommend that i get some laser goggles. i've been looking online and laser goggles are really expensive. i really want to have some for my own safety, but before i spend $40 on them, does anyone know of anything i can use in place of laser goggles? maybe sunglasses etc.?

 

[LSRFAQ]

At 200 mW , your going to want real goggles. The problem with any substitute is testing. Dyes in substitute materials may bleach, or the material may burn. It may not happen on the first exposure, but it may happen on the next. Generic goggle clones start at 35$. Professional goggles are around 100$ used and 250-450$ new.

Retinal replacement is impossible, even a OD4 generic low cost goggle is much better then trying homebrew without a calibrated milliwatt meter.

No, welding glass, theatrical gels, sunglasses, colored lexan or plexiglas, or photographic filters DO NOT provide enough protection. All have been suggested, but when examined, all fail.

Sorry, but you need a specialized plastic colored with the right amount of the right dye, or glass colored with the metallic ion in the mix.

A eye is a terrible thing to waste, or worse, damage.

Steve

 

[Benm]

It's a matter of perspective though. Especially with red diode lasers, there is only one single wavelength to worry about. At 200 mW, any OD2 (100 fold reducing) goggles will suffice to reduce the danger to eye safe levels.

I'd still recommend going for something that guarantees OD value for 660-630 nm or so, but it need not be anything special beyond that. Also, you should test for endurance by shining the laser through an edge of the goggles to see if it melts, bleaches or otherwise deteriorates within in minutes.

In general, the advantage of red is that you can tell something is effective by just looking at it - very different from greens where you can have invisible IR leaks that are not blocked by generic bad quality protection.

 

[LSRFAQ]

It's a matter of perspective though. Especially with red diode lasers, there is only one single wavelength to worry about. At 200 mW, any OD2 (100 fold reducing) goggles will suffice to reduce the danger to eye safe levels.

I'd still recommend going for something that guarantees OD value for 660-630 nm or so, but it need not be anything special beyond that. Also, you should test for endurance by shining the laser through an edge of the goggles to see if it melts, bleaches or otherwise deteriorates within in minutes

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Sort of correct.. I see your point, but....

A laser safety officer would not specify OD2 for the simple reason that just a 100 fold reduction still exposes you to a 2 mW beam, with a 1 in 99,999 chance of damage by being in the class IIIA power level. This is why OD3-4 are the minimum that are sold by reputable makers. He could probably find a OD2 material in stuff in town, but OD3 gets tough to make at home. At OD4 its gonna be a specialty plastic..

CLASS IIA is the low risk classification, class IIIA does involve a minor risk of damage, and 2mW is downright painful, with afterimages. The lower laser classes were set up based on statistical tests in humans (dead) , cows (dead) rabbits, and monkeys/chimps. IIIA is NOT intrinsically safe, its a reduced hazard of damage.. So he needs to get down to .1 mW or so. OD3-4 were to be sold for alignment purposes only, but standards enforcement is getting loose. A LSO will tell you if your seeing afterimages he/she has NOT done their job.

class IIA is something like a 1 in 999,999 chance, class IIIA is 1 in 99,999 chance of injury.

Remember there are other hazards then eye damage. "Secondary Reaction" is a physical injury incurred when disoriented or from reacting to the painful flash. Ie you jump up and hit your head on a pipe or filing cabinet. So you size the goggles to get down to microwatt levels. :can:

And remember there is the slight chance of "AIDED VIEWING" , using a microscope or a camera viewfinder with magnification, so a extra order of magnitude is justified.

I know, he's a hobbyist, but turning pro early is a good thing.

A LSO will also tell you to turn the room lights up, least your goggles be so dark as to be a trip hazard in the lab. This one of the reasons why multi wavelength goggles are so unpopular, they can become more of a hazard then a properly constructed experiement with beam blocks and beam tubes.

STEVE


I will stick to my guns on NOT encouraging the making of home made safety glasses.

 

[Bluefan]

I usually don't rant that long but I completely agree
What would be the chances of eye damage at 5mW? 1 in 99,999 sounds very low for class 3a.

 

[Benm]

There is always risk and statistics - i'm trying to be practical here, intended on hobby use, not a professional environment where laser exposre is an occupational hazard and some employer is liable for any (indirect) damages caused by whatever mechanism.

That said, getting 1 or 5 mW into the eye is something that should be avoided. Think of it like loosing a pint of blood: chances are very good to survive without lasting injury, but that doesnt make it a good or desireable idea.