Do you need safety glasses when a star cap is equipped?

Hi guys, after buying a high priced laser I figured i mess around a bit with the cheap ebay ones. My hope is to get a 405nm violet laser (with as low amount of wattage as possible) and for it also to include a star cap!

here is the one i am looking at now:

New 405nm Blue Violet Laser Pointer Light Pen Single Beam 5 Caps 2 Battery | eBay

it claims its only 5mW but its *obviously* going to be overspec unfortunately, and assuming that it hopefully shouldnt be too high of wattage i was thinking about picking up a couple of these cheapies as well:

Laser Safety Glasses Eye Protection for Green Blue Lasers Without Case | eBay

My question: when the star cap is equipped for something like this, is it safe to not use safety glasses since the beam is being diffracted? Or should i still be wearing them even while the star cap is on?

Thanks in advanced,
-Antonoviich

If you're just going to shine it at a wall then common sense applies and says no you don't need to put on glasses. If you want to wave it around the room or try bouncing it off one of those crystal ornament things then yes.

Obviously it's a good idea to have glasses on hand but if you wear them constantly you wouldn't ever see the laser so what's the point...

I observe my 1.6 Watt blue laser in my front room (on its stand, facing away, defocussed) without glasses. When burning or taking photos, glasses on always.

"trencheel" summed it up nicely.

Personally, for extra safety I would recommend always wearing glasses around those "pen-lasers". Im sure you will be safe with it but remember, it only takes one hit

Best of luck and get us some nice pics

thank you guys!

So with safety glasses, is it just wave cancellation? Whats the science going on with them?

And when you wear the glasses can you actually not see any of the laser (whether it be the dot or the beam) at all, or does it just dim it?

:thanks:

Once you get it metered out, and get to see the "diffractiveness" of the grating, i.e. how many beams it splits out to, you can make your decision then. You will want to meter the central "star" by itself, as that will be the most powerful of all dots.

One thing that should also play into your decision is how much trust you put in these gratings. If the grating burns through, then out of nowhere instead of, say, 50 1mW beams fanning out, you instantly get 1 50mW beam.

Antonoviich said:

thank you guys!

So with safety glasses, is it just wave cancellation? Whats the science going on with them?

And when you wear the glasses can you actually not see any of the laser (whether it be the dot or the beam) at all, or does it just dim it?

:thanks:

Click to expand...

You see a tiny dot on the surface you are shining the laser on. No beam. You only really see the dot because of fluorescence of the object the laser is shining on, and only a tiny, tiny, miniscule amount of that actual laser light will ever get through the glasses.

I take my glasses off once my lasers are positioned if I am doing a sort of "laser show" in my front room. I have a general rule though that if I am moving the glasses go on, in case I trip and send a laser flying and :eg: my eyes.

trencheel303 said:

You see a tiny dot on the surface you are shining the laser on. No beam. You only really see the dot because of fluorescence of the object the laser is shining on, and only a tiny, tiny, miniscule amount of that actual laser light will ever get through the glasses.

I take my glasses off once my lasers are positioned if I am doing a sort of "laser show" in my front room. I have a general rule though that if I am moving the glasses go on, in case I trip and send a laser flying and :eg: my eyes.

Click to expand...

okay thank you :yh:

and one last question, unfortunatly the search bar couldn't help me find the question i was looking for. But for something like the 405nm laser im ordering (approximately 30-80mW) would the cheap safety glasses i linked above be just fine for such a low wattage? or do i still need higher class glasses?

here's another link: http://www.ebay.com/itm/161191667104?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Antonoviich said:

okay thank you :yh:

and one last question, unfortunatly the search bar couldn't help me find the question i was looking for. But for something like the 405nm laser im ordering (approximately 30-80mW) would the cheap safety glasses i linked above be just fine for such a low wattage? or do i still need higher class glasses?

here's another link: Laser Safety Glasses Eye Protection for Green Blue Lasers Without Case | eBay

Click to expand...

They should work fine since they are still withing the wavelengths the goggles protect.

I know this mostly has been said many times but try and get these as soon as possible. These are one of the best out there and will last you forever

Eagle Pair® 190-540nm Standard Laser Safety Goggles

405nm lasers or as i like to call the 'teensy blacklights on crack' are a decepitively dangerous wavelength.

Example I added a '5'mW 4$ pointer to a box I was sending to honor the tradition started at LPF by some who came before me. It had fairly new aaas in it. The guy getting these is no kid but relatively speaking no laser expert by any means.

He wrote me right after finding the surprise that it MUST have almost dead batteries in it as the spot was quite dim compared to his 650 reds- SO he says he gave it to his children to 'play' with. <WTH>


And some wonder why we can be almost 'anal' about safety and why I say there is NO eye safe laser period. The point being is: if no lasers are considered safe for youngsters to play with then NO lasers will/should EVER be considered toys.

Here is how 405 can be so bad-- it is the opposite of the 514- to 532 nm greens- a 5 mW green pointer looks dangerously bright and thus to our eyes

So.. we see two spots on the wall as being 'equally' bright even tho the green is 50mW and the 445 is 1W-TRy it-- its easy to agree especially if you are some distance away.

So.... our eyes and, thusly, our pupils will react the the preceived brightness by DIALATING- the 'normal' 7 mm opening will be larger- allowing even more 405 into the eyes which CANNOT feel any pain and you can end up with a hole in your retina that may NEVER go away w/o laser surgery (ironic --YES?)

Of course if you are LOOKING directly at any laser the results are worse-- if you manage to resist the automatic reaction of looking away- closing your eyes or blocking the beam with your hand (generally accepted to be .25 seconds) etc things become much worse. If the laser is static this is also worse.

Even just shiny or white targets can make a light too bright to be considered safe and forget mirrors or windows- while they will be less bright that a direct hit the difference is too small to consider at all.
A fairly good rule of thumb is: if you see after images (like we see when we take a peek at the sun) and these linger --you saw too much light.

For audience scanning if our eyes are trying to delete the afterimages we are then missing the next part of the scan- making the whole thing much less enjoyable and more likely to be too much to be considered safe.

I was just asked ( again) which laser and at what power would one need to pop balloons at distance, say at 15+ feet. The first time I was asked was actually by a mature adult who runs a banquet hall and the leftover helium balloons for event were a problem. So I steered him towards a 500mW 405 JETLASERS PL-C laser and AFAIK problem solved. Of course having both the laser and targets static helps a lot as well as dark colored balloons VS white ones.

405s are also quite often a very small dot and great divergence and this also make the Blu-Ray the best visible burner.

SO I see no real point in even seeking a 5 mW anything- if its eye safety one claims to be interested, they would not even be looking for a SAFE laser as IMHO there are NONE!!


end rant

I want a <1mW but with a super tiny beam and good divergence. Somebody make these diodes smaller, eh?