405nm laser safety?

[ilovelasers93]

hello everyone

i have recently bought a 20mW 405nm laser module of ebay and am wondering what i need to know about safety for this item

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

what would be considered safe use of this as a pointer

cheers

 

[Misanthrop]

MMS: Error

 

[proud2deviate]

A lot of these Chinese pointers and modules are wildly over-spec, so I wouldn't put too much stock in the 20mw figure. There's a decent chance it's more powerful than that.

As for safety, that's probably subject to opinion. There are folks here that might tell you to treat it like a firearm and not point it at anything you don't intend to destroy. That's a bit extreme, I think.

For starters, don't point it at your eyeballs, or the eyeballs of anyone or anything. In fact, give the whole eyeball area a wide berth. Avoid specular reflections that might bounce at unexpected angles and come into contact with eyeballs of any description. That means be bloody careful when you point it near shiny stuff.

This laser will not give you cancer.

This laser does not emit infrared light.

This laser will never threaten to stab you, and in fact, cannot speak.

This laser might infect your wallet with an immunodeficiency disease.

 

[laserdan]

In my opinion, the biggest danger of 405nm lasers is that they are WAY brighter
than they appear to be, thus luring you into a false sense of safety or into complacency.
This is because your eyes aren't very sensitive to 405nm.

I realized this when I took a video of some cats with my phone once, while playing with them with my low power 405nm laser. The spot on the video was WAY brighter than it appeared the the naked eye. It was so bright in the video, that it instantly made me think that I ought not use that laser to play with cats any more.

Another thing weird about 405nm is that your eyes focus on the fluorescence of what ever the laser strikes, not the purple itself. This makes it uncomfortable to view the spot in may cases, and not friendly at all to strained or tired eyes.

Dan

 

[ilovelasers93]

thank you for your replies
so as long as there is no direct or reflective contact of the laser with my eyes there is no great danger in using this without safety glasses?

i have aslo read that green is the most visible wave lengths, would a green laser of same power be much brighter? aslo will i have to worry about IR with a green laser?

Cheers
Jordan

 

[proud2deviate]

No great danger, so long as a modicum of common sense is exercised.

laserdan makes good points about some of the unique properties of 405. It will be much more powerful than it looks because your eye probably won't pick up on the raw color too well. Once you point it at something fluorescent, the perceived brightness of the dot will increase. While not the most medically sound or scientific advice, you generally know when something is bad for your eyes. If looking at the dot on a wall dazzles you, step back from it another meter or three. There's a little part of your brain that kicks in when stuff is too bright and says, "Umm, maybe we shouldn't be looking at that." Listen to it.

A green laser of the same power as a violet will be much, much, MUCH brighter, relatively speaking. Green lasers on the market today convert infrared light to green, though not entirely efficiently. Some greens have IR filters, most do not. You just have to know that the IR is there, you can't see it, it can be a lot more powerful than the green part of the beam, and it can hurt you if you're a dumbass.

 

[ilovelasers93]

thank you for your help, but do you think i can be a pain and ask if anyone knows of any relatively cheap green laser modules that have IR filter fitted?

Cheers
Jordan

 

[TuhOz]

thank you for your help, but do you think i can be a pain and ask if anyone knows of any relatively cheap green laser modules that have IR filter fitted?

Cheers
Jordan

You can buy the Ir filter and add it to the module...
IR filters are ~2-4$ each