Sunglasses for 15-50 mW lasers?

[Ghostchrome]

Cheaper, like I said.

:shrug: It's your eyes.

 

[laser_freak]

String as a seat belt for a car?

I suppose if it makes you feel better, but it won't actually do anything.

 

[donjoe]

Typical troll no

No indeed. What I said was "typical troll answer", with emphasis on "answer". A single troll-like remark doesn't make you a troll generally. So no, I didn't actually call you a troll.

Sick of this question being asked yes

That's because you're not paying attention. My question was not the same as the one that's been asked around here a million times: I actually took into account the real-world absorptive power of sunglasses and the kinds of lasers they could realistically protect you from.

it sunglasses have on average od of 1 mabye 2

If sunglasses ever got to OD2, they'd be mistaken for welding glasses, LOL. Even OD1 is only for the highest quality sunglasses, since it means 10:1 (or 90%) absorption. Regular sunglasses will have less than OD1, maybe something like 4:1 (or 75%) absorption.

and that is simply not enough

It can be, depending on the laser you're going to use, hopefully following a choice made with your brain.

String as a seat belt for a car?

Nope. If you pay attention to the proportions I mentioned, it's more like string as a seat belt for a children's tricycle. Not everyone is a maniac running around with a 1W+ laser, dude.

 

[Benm]

I guess being into real world performance and application is fine.

The only way to ensure your sunglasses provide protection is to simply shine a laser through them, see what the power reduction is, and see how long it lasts (in case the sunglasses degrade from bleaching or another mechanism).

If your measurement show that a pair of sunglasses effectively reduce the power by 80%, that would increase the amount of power you can safely work with 5 fold - not much to discuss on that.

One problem is that not all sunglasses are equal and most dont have any specifications at all. So your findings will be unique to the pair you have in your hands, and can never be applied to sunglesses in general.

Realistically i think that virtually anyone that spends money on a power meter is also willing to spend money on proper goggles.

 

[donjoe]

Realistically i think that virtually anyone that spends money on a power meter is also willing to spend money on proper goggles.

Unless they have a friend with a power meter.

But for 80% absorption or less you may not even need a power meter - this kind of transparency can be checked with much easier and cheaper methods, e.g.:
- Display an area of pure green somewhere on your monitor (pure green means RGB=255/255/255 or HSL=85/255/128)
- Display an area of relatively dark red right next to it
- Cover the green area with your sunglasses and compare the resulting (filtered) colour to the unfiltered dark red you have right next to it
- Adjust the hue and luminance of the unfiltered dark red and re-check, adjust again and re-check, until the two colours match as closely as is possible for you to determine
=> Your glasses are absorbing (Luminance_of_green_area / Luminance_of_dark_red_area) * 100 [%] of incoming green light.
Easy.
(Of course, the test colours need to be different if your laser isn't green.)

I just used this method last night to determine that the red lens on my red-cyan 3D glasses absorbs about 80% of all incident green light, while the red plastic cap I have for my tactical flashlight absorbs only around 68%.

 

[Bluefan]

Let's be serious here, that list isn't really that long. The most important aspect of this is that official laser safety requirements are meant to deal with the absolute worst-case scenario, where 1. you're being a total idiot and shining the laser directly into your eye for 10 seconds or more or 2. a criminal has you tied to a chair and just happens to decide to shine the laser directly into your eye for 10 seconds or more. ) Well, as it happens, I never addressed this topic to the idiots out there, nor was I suggesting that sunglasses could offer adequate protection against criminal assault.
As long as you're being at least semi-rational in the use of your laser and in the expectations you have from your eyewear, sunglasses should be fine for certain power levels.

I'm serious too, for the EN207 (besides the 10second/100pulses) glasses would have to conform to this:
- no Q-Switch-Effect
- low dioptrical effects
- quality of materials and surface
- low stray light < 0,5 cd/m²lx
- no secondary radiation
- UV-resistance
- thermal resistance
- field of vision >40°
- shatter resistance
This isn't a simple list but just the table of content.

Never said you did. You have to measure the real absorptance of your sunglasses before relying on them for any kind of protection, that much is clear.

That doesn't guarantee everything. Does it bleach under a direct hit? Under long time indirect exposure? With only a few milliwats this won't matter much. The probably would work, but it's the "probably" that's the problem, I wouldn't trust my eyes to a few $ thing abused as safety glasses. I don't have cheap noname nocertification laser safety glasses either.

No I don't think I can be sure of this. Quality sunglasses can reach an absorption power of 5:1 (or 80%). A pair of these could enable you to play around with a 25mW laser without worry (and without buying unnecessarily expensive OD2+ safety glasses or whatever).

A brick reaches a higher OD. Sunglasses are not very practical, and you're pushing the limit.

Too bad for you. Reports of the damage potential of 5mW have been greatly exaggerated. See here: Laser safety - Wikipedia, the free encyclopedia

Reports of traffic accident are exaggerated too, I had one and the car flipped over at quite some speed but I could walk away with it without needing a doctor.
I don't care about exaggeration, I don't walk close to the line of what we consider safe, I don't push to the limits on safety, I take some margin. Being on the edge like that will have you fall off sooner or later, it's just not wise to do.

Nope, I never plan to take that chance. I'm not the kind of person who thinks the limits of physics are something meant to be "pushed" (i.e. I don't believe in magic).

Then get some safety margin, or even better, use real laser safety eyewear, that would be the right thing to do.

As with all types of safety, the single most important contribution you can make is being smart about what you're doing, paying attention to your every move, planning it in advance etc. No protective material or device in the world can save you from human stupidity. If you're not wearing 100% bullet-proof protection but are being smart, you can get away with certain otherwise risky behaviours, but if you're wearing protection and being a total jackass, you have every chance of hurting yourself and/or others despite the protection.

That's not smart. Glasses are not some holy perfect protection, but neither is common sense! Accident happens, even in labs with proper safety precautions. Glasses are ment to be an extra line of defense, the last one that should never fail, but trusting on a single safety measure is taking a risk. So be smart, plan where your beam goes AND use proper laser safety eyewear!

This topic is not meant as a recommendation for anyone to ignore proper safety glasses if they're going to use a laser with a power output higher than 50 mW. This topic is meant to suggest that smart people who know exactly what they're doing with their <50mW laser could get adequate eye protection without buying safety glasses that cost more than the laser itself, if (and only if) they can find quality sunglasses that absorb enough light to prevent anything above 5mW from hitting their eyes. This topic is not meant for stupid people, it's meant for smart people.

That "know exactly what they are doing" is commonly overestimated but even with pro's it can go wrong. Smart people take safety serious and take proper safety precautions. I don't consider people using sunglasses as laser safety eyewear smart, I consider anyone recommending them stupid.
This isn't about "they will work", it's about safety. Accident are accident after all, things sometimes go way different than you though they would.

If you're always insisting that people rely completely on officially approved passive protection, you're essentially cultivating stupidity and you risk doing more harm than good. The same thing happened when sunscreen manufacturers told the population that sunscreen lotions kept you completely safe from solar radiation: people used sunscreen, relied on it completely, way beyond its capacity to protect, and they ended up getting more skin cancer instead of less: they thought just because they were using adequate and officially approved passive protection they didn't have to be smart anymore.

That's twisting the point, we never said stupidity is allowed with certified laser safety eyewear. Stupidity is never good, sunglasses aren't good either.

That's because you're not paying attention. My question was not the same as the one that's been asked around here a million times: I actually took into account the real-world absorptive power of sunglasses and the kinds of lasers they could realistically protect you from.

But you forgot everything else besides that single number.

If sunglasses ever got to OD2, they'd be mistaken for welding glasses, LOL. Even OD1 is only for the highest quality sunglasses, since it means 10:1 (or 90%) absorption. Regular sunglasses will have less than OD1, maybe something like 4:1 (or 75%) absorption.

That's wrong. High quality doesn't mean high absorbtion and the other way around. Those are NOT connected in any way.

It can be, depending on the laser you're going to use, hopefully following a choice made with your brain.

Or it might not, that's the problem.

Nope. If you pay attention to the proportions I mentioned, it's more like string as a seat belt for a children's tricycle. Not everyone is a maniac running around with a 1W+ laser, dude.

To follow in the metaphor: That would would actually do more harm than good

I leave it at this.

 

[donjoe]

This isn't a simple list but just the table of content.

I've already discussed the worst-case-scenario aspect of those regulations.

Sunglasses are not very practical, and you're pushing the limit.

Except when you aren't.

I don't walk close to the line of what we consider safe, I don't push to the limits on safety, I take some margin.

Margins are good, but different people can still disagree on what the right margin is. When you think about it, the safest thing to do is to just never use lasers at all (and maybe walk around with OD5 protection glasses all day long just in case a nutjob happens to shine something at you), but somehow I don't think you're going to do that. There's always an element of personal preference, even in something as serious/important as protecting your health.

Glasses are not some holy perfect protection, but neither is common sense!

Never said it was, I just said common sense was more important/effective than glasses.

Glasses are ment to be an extra line of defense, the last one that should never fail, but trusting on a single safety measure is taking a risk. So be smart, plan where your beam goes AND use proper laser safety eyewear!

Absolutely correct - glasses are one of the tools in your rational arsenal and using glasses is one of the multiple possible smart behaviours you can include in your routine. The point was that being smart is more fundamental.

I don't consider people using sunglasses as laser safety eyewear smart, I consider anyone recommending them stupid.

Thank you. I guess it was just a matter of time before someone introduced insults to this topic, but frankly you're the last one I would've expected to see doing it.

we never said stupidity is allowed with certified laser safety eyewear.

You don't have to say it, it's implicit in a discourse that repeats "get good glasses" far far more often than it says "oh, and be smart". This is the kind of discourse I've seen on every topic about protection in this forum.

 

[Benm]

Lets leave the insults out of this. I guess this can become a discussion that goes on for all eternity, while there is little reason to.

I'd just say sunglasses can give a bit of protection for lasers that are just over 5 mW, with a lot of ifs and buts.

I wouldnt rely on it myself, but if you insist on using sunglasses as a safety measure, go ahead. Its unlikely to make things worse (compared to no glasses at all), unless you start to rely on them and do things that you would not do without them (like looking straight into the beam). As for being practical: sunglasses that reduce visible light by a factor of 10 may make working indoors rather clumsy

As bluefan pointed out there are a lot of additional requirements for certified goggles, but some of those may not be all that relevant when working with 5 - 50 mW lasers. The only one that would really concern me is the q-switch/bleaching effect, but that can easily be tested.

 

[TuhOz]

Wow this thread.
donjoe, I just tested 5mw laser by pointing it normallty and trough sunglasses. I didnt notice any diffrence.

Seriously said, i would never use sunglasses as safety goggles.
Not even with 20mw laser.

 

[donjoe]

I just tested 5mw laser by pointing it normallty and trough sunglasses. I didnt notice any diffrence.

Then you need better sunglasses and/or better eyes.

 

[bennett326]

Then you need better sunglasses and/or better eyes.

if your buying a nice pair of sunglasses why not by some safety glasses:wtf:

 

[donjoe]

Because if he buys better sunglasses he will also have the benefit of, well, better sunglasses. You know, for going out in the sun.

 

[Ghostchrome]

 

[bennett326]

great answer (insert sarcasm here)

now your trolling heh

 

[donjoe]

now your trolling heh

Nah, that's just your imagination running away with you. What I'm doing is avoiding repeating myself while some of you keep asking questions already answered up-thread. I don't like being repetitive or pretending not to understand plain English text, like you, so I prefer to move on to cracking jokes when that happens.

 

[Bluefan]

Thank you. I guess it was just a matter of time before someone introduced insults to this topic, but frankly you're the last one I would've expected to see doing it.

I could have stated it less harsh, my apologies, but I can't call people recommending sunglasses as laser safety particularly smart. Real laser safety glasses are far better, besides the debated safety aspects of them they have a far higher VLT and a clear and easy trustable rating.