Laser protection goggles

[masterpj]

Hello I'm masterpj

Im getting my RGB projector soon.
However just in case i'd like to buy myself some laser protection goggles/glasses.
I have 0 experience with them.

Is it possible to have a pair and still be able to see the lasers / the colours a bit?


If yes, Great.. which ? and do they provide suffient protection?

Amd which goggles/glasses are recommended?

[andy_con]

eye lids ?

[masterpj]

eye lids ?

hahaha
eye lids?
but I will still be able to see the beams

Well just in case to clearify it a bit.
The total power of the RGB should be lower that 1 watt

[mccarrot]

Is it possible to have a pair and still be able to see the lasers / the colours a bit?

Yes, dont just buy a cheap glass from ebay as they will just block the complete beam and will be complete useless. and complete waste of your money

Good glasses will have a OD value written on them (OD=Optical Density) and a specific wavelengt.

Glasses with a OD2 will transmit 0,01 x the power or 1%
Glasses with a OD3 will transmit 0,001 x the power or 0,1%
Glasses with a OD4 will transmit 0,0001 x the power or 0,01%

For a 1W laser a OD3 will be fine, this means if you get 1W at the glasses 1mW will be passed trough.

[masterpj]

Yes, dont just buy a cheap glass from ebay as they will just block the complete beam and will be complete useless. and complete waste of your money

Good glasses will have a OD value written on them (OD=Optical Density) and a specific wavelengt.

Glasses with a OD2 will transmit 0,01 x the power or 1%
Glasses with a OD3 will transmit 0,001 x the power or 0,1%
Glasses with a OD4 will transmit 0,0001 x the power or 0,01%

For a 1W laser a OD3 will be fine, this means if you get 1W at the glasses 1mW will be passed trough.

Thanks for the quick response.
And helpfull.
I know what to look for

[buffo]

Just to clarify: laser safety glasses should be selected so that you are protected against a direct strike by the full power of the projector. That means getting the power level down below 1 milliwatt. Thus for your 1 watt projector, you want OD3 goggles at a minimum.

But remember that while wearing these goggles, even though you will still be able to see the dot the laser makes on the wall (or on a mirror, or a dichro, making alignment possible), you will *not* be able to see the beam in the air.

Adam

[masterpj]

Just to clarify: laser safety glasses should be selected so that you are protected against a direct strike by the full power of the projector. That means getting the power level down below 1 milliwatt. Thus for your 1 watt projector, you want OD3 goggles at a minimum.

But remember that while wearing these goggles, even though you will still be able to see the dot the laser makes on the wall (or on a mirror, or a dichro, making alignment possible), you will *not* be able to see the beam in the air.

Adam

Thanks and that's ok.
I will be doing graphics more often anyway

[buffo]

Ok - then once you have your projector aligned and aimed in a safe direction, you can take your goggles off and enjoy the cool graphics shows.

It's just that a lot of new people think that they need to wear their goggles all the time, when that's obviously not the case. Goggles are for assembly, alignment and maintenance work. Just wanted to clarify that.

Adam

[masterpj]

Ok - then once you have your projector aligned and aimed in a safe direction, you can take your goggles off and enjoy the cool graphics shows.

It's just that a lot of new people think that they need to wear their goggles all the time, when that's obviously not the case. Goggles are for assembly, alignment and maintenance work. Just wanted to clarify that.

Adam

Aha thanks for that.
But is there a danger for reflection at for example a white wall?
I got a huge location here really it's brilliant for beamshow and graphics and testing.
My room has decent size but it's smaller then the main room and the projector will be on my desk which is pointing at the wall.

Should be safe right?

[buffo]

But is there a danger for reflection at for example a white wall?

That depends on a number of factors, including how much power you're running, how brightly lit the room is, how close you are to the wall, how far away from the projector the wall is, and how smooth or rough the wall is.

As a general rule, a 1 watt projector is going to be OK to view at a distance of 15 ft or greater, assuming the projector is an equal distance away, and assuming that the wall is painted with a flat (not gloss or semi-gloss) paint. More light in the room will increase the safety margin (your pupils will constrict, allowing less light to enter).

Bottom line: if it seems too bright to your eyes, if you find yourself having to squint or shield your eyes, or if you get a headache from watching it, then reduce the output power of the projector or increase your distance from the wall.

If you see after-images, it's definitely too bright!

It's rare to suffer permanent damage to the eye from a diffuse reflection off a wall, even at power levels of 1 watt. However, it's not unheard of. So be careful. And make *sure* there are no reflective surfaces on the wall. (Watch out for things like picture frames, windows, metal light fixtures, etc.)

My room has decent size but it's smaller then the main room and the projector will be on my desk which is pointing at the wall.

That *should* be OK, but you may want to reduce your projector's power output when running it on your desk just to be sure. (See if your controller has a beam attenuation map or master brightness control in software to do this.)

Worst case, set it up with the room lights on first, and see how it looks. Then turn the lights off. If it suddenly becomes too bright to look at with the lights off, you know you'll need to turn the power down.

Adam