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FrozenGate by Avery

laser googles OD too high

A

anthell

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Oct 13, 2010
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i just bought the OEM laser safety goggles with OD of around 8 or so for 445nm..

i think it does a little too good of a job that i can barely see anything even with my 1.6W from DTR..

my problem is, with the laser being near invisible, i cant exactly see the beauty of it and hard to tell exactly where im pointing it at...

i know the danger of pointing such a high powered laser in door so i want to be able to actually direct it correctly, while also see the awesome beauty of its beam..

again, safety is of highest priority but right now, that laser is so dim a 5mw 532nm is brighter without goggles.

if anyone has a better suggestion of a goggles that is just right my need i would appreciate it
 
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Its a bit of an eternal trade off: you want to be able to see what you are doing, but protect yourself from that light at the same time. Those are obviously conflicting wishes.

I would suggest getting eyewear that has enough OD to drop the laser power to safe levels, but not very far belowthat. For example, if you are working with a 1 watt laser, OD3 goggles would be fine, since they would limit any direct exposure to a safe 1 mW. The 1 mW equivalent dot can easily be seen, and you can even see the beam to some degree, depending on air conditions.

Very high OD goggles are a bit of a hazard really - you could accidentily stick your hand in the beam or something like that, since you will not be able to see anything you're doing.
 
The difficulty in choosing eye protection is that it was never designed for hobbyists so you get OD and VLT ratings that don't quite fit the needs. For example the ARG filter we offer is OD7 which, at the moment, is quite high for the output powers available for common hobby type lasers but it protects against 405nm, 532nm, 445nm, 473nm, 488, and 514nm which are common wavelengths for hobbyists. It kills many birds with one stone for a single low cost purchase. The VLT is very high.

You can get OD3 in the AL3 filter which will protect against the same wavelengths but the VLT is much lower because the response curve covers out into the red even though it's not certified for that range.

The YLW gives OD5 for 445nm and a narrow range around it with awesome VLT but you don't get protection for multiple laser wavelengths which ends up costing more because you need to purchase multiple glasses.

The difficulty really lies in the means of determining OD requirements. In laboratory settings there is usually a laser safety officer who looks at the output power, the experimental set up and various other probabilities, along with some calculations to determine what OD is best for the operating environment. An LSO may calculate an OD5 requirement, for example, yet only require OD 2 or 3 based on the use and setup of the system.

The best rule of thumb is to get to class II range but in the hobby many feel class IIIa is more appropriate an exposure. You kind of have to determine your needs based on how you intend to use the laser and realize the filter may or may not be appropriate for all uses. It's a very complex issue. The powers available now will damage your retinas in less than the blink of an eye so it not a matter of should I get eye wear but what specifications to get. My recommendation is to do your homework and learn about laser safety. I see far too many filters, as an example, listed as CE EN207 certified yet only list an OD. If they only list an OD they are not EN207 which begs the question, "are they even really certified by anyone." (EN207 does not use OD. They use L ratings broken down by exposure time D/I/R/M) It's little subtleties like this that can have a profound impact on whether you end up damaging your eyes. Be a smart consumer and learn all aspects of operating your lasers.
 
FrothyChimp you're spot on!
There's also the EN 208 certification for alignment. These ratings are for alignment goggles, bringing the laser power back to class II levels. They have a R rating, for example R2 allows 0.1W or 2 * 10^-5 J (see also here)
 
Aiming for class 2 or 3A after the goggles would be sensible - that still allows you to observe the laser light, yet offer enough protection in case of even a direct hit. 3A would be a calculated risk there, but you shouldn't shine yourself in the eye with a laser itentionally even with protective eyewear.

If you get something like OD8 you actually might do just the latter, and not even notice until you see your glasses smoldering away :D
 
If you buy another pair, for 445nm I'd suggest the YLW. It has a very high VLT, so you can see everything around you (I find the red goggles hard to see with), it has sufficient protection of 445nm at OD5, and it covers the shorter wavelengths as well.

For other wavelengths consider the ML7, especially for greens, since it filters out the IR that may leak out. They're multi-purpose and good for lower-powered reds as well, but are not certified for and do not work for 445nm or other blue wavelengths.

Those two goggles are my main pairs for all intents and purposes.
 
I went with the AL3 OD3 that Frothy mentioned for my 1.2W 445 and have been very happy with them. While the beam is completely blocked (as expected) the dot is very visible. You can still see a bit of blue from the dot if it's close which I like. I think I'll be ordering the actual goggle style next time because I've noticed if the dot's close to me (i.e for burning) there's a pretty good reflection coming off my shirt if I happen to look down. I don't think that type of reflection is a problem but I'd rather not chance it.
 
I picked up the ARG goggles with an OD7 rating. I wanted to use the goggles for multiple wavelengths and I wanted good protection for the 445nm lasers given their high power. I use the goggles for when I'm burning stuff or generally shining it around in doors. If you wanted to see the beam outdoors, I don't see a significant problem with not using the goggles outside as long as you are pointing it far away and there's no chance anything will cross the beam path near you (ie sky pointing).

When I'm getting up close an personal with the laser while burning I want to make darn sure I'm well protected as that is where the highest risk would seem to be. You could certainly get by with lower quality protection but I just didn't feel it was worth the potential risk, with the ARG OD7 goggles I can see the dot on my 445nm just fine, the only thing I am missing is the beam which isn't a huge deal when burning stuff.
 
oh, its safe to point such laser to the sky w/o goggles?

and is it generally safe to do that with such high powered laser?
 
anthell said:
oh, its safe to point such laser to the sky w/o goggles?

and is it generally safe to do that with such high powered laser?
Click to expand...

I think possible. I shine my Spartan 1W without wearing goggles to the sky with no problems
 
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anthell said:
oh, its safe to point such laser to the sky w/o goggles?

and is it generally safe to do that with such high powered laser?
Click to expand...

Absolutely, it is not looking at the beam its self that is dangerous, it is the dot where the beam terminates that is a problem. So as long as it isn't terminating near you (ie hitting a wall, rock, floor etc...) then you should be ok.

However, if you are pointing it in the sky please make sure there are no aircraft of any kind where you are pointing, not only is that dangerous but highly illegal to point a laser at any aircraft.
 
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