Proper eye protection for an rgb laser?

[midnightchime]

So I am making big plans to build a powerful rgb laser but I am not sure how to properly protect my eyes from a beam combined with different wavelengths

 

[Pi R Squared]

So I am making big plans to build a powerful rgb laser but I am not sure how to properly protect my eyes from a beam combined with different wavelengths

You can't quite do that, get safety glasses for blue/green and just be very careful. You could get glasses for red and then some fit over glasses for blue/green and wear both at the same time, but if you did that then I doubt you would see much of anything, but if you will do any burning with it then you should try it.

Alan

 

[diachi]

You can't quite do that, get safety glasses for blue/green and just be very careful. You could get glasses for red and then some fit over glasses for blue/green and wear both at the same time, but if you did that then I doubt you would see much of anything, but if you will do any burning with it then you should try it.

Alan

Actually, you can get glasses for RGB - They had quite a sharp drop at the low end of the blue so everything looked purple through them. I had a pair back in Scotland.

That said - and others who have built projectors may want to comment here too - glasses aren't much use when you're trying to build a projector because you need to be able to see the output to align things correctly. They also aren't any good if you're watching a show because then you can't actually see the show... I'm not saying don't get glasses, they are good to have, but there are a lot of situations with a projector where they are no use. Use common sense and follow other safety procedures, don't rush anything.

Procedure we used was to measure everything out first, drill and mount everything, make sure it's all tight and secure, then adjust everything. Usually we'd have a beam stop of some kind on top of the galvo block in case the beams either missed the top mirror or were too wide to fit leaving some splashing over the sides.

It's a good idea to make sure any optics adjustment knobs/screws or other pieces of mounting hardware are clear of the beam path to prevent either burns to your fingers or reflections from any tools you're using.

For alignment, project a circle on a wall several meters away and adjust the optics as necessary to create a white circle with all of the colours lined up both at the sides and top of the circle. EDIT: Actually, if you can project further than just a few meters alignment will be easier and itll be more accurate too. A few meters does the job though.

I know a lot of people will disagree with my advice here, but you try aligning an RGB projector when you can't see anything.

EDIT

Also, go with analogue modulated lasers - that way you can turn down the power for alignment, might not get it down to 5mW but you'll at least get it down close to threshold and a significantly lower power. You'll lower your risk of eye damage and your risk of burning yourself/your curtains/your walls. Plus analogue modulation gives you so much more versatility when projecting compared with TTL.

You'll want glasses if you plan to look at the dot up close or do any burning ... not really the point of an RGB projector but it has to be done from time to time...

Laser Wave used to sell the RGB glasses, don't know if they still do.

 

[midnightchime]

Any advice is highly appreciatedd. I am learning as I go with this. Ive been working with lasers for 10 years and have grown slightly, only slightly bored of my laser builds. This is what I have in mind making now https://youtu.be/vrwxUbrYNgA .....This laser is ***Y. But I want to make a more powerful version of it. I plan to use these diodes together with it but I am not sure if they are compatible in beam combining. (Red) Oclaro 700mW 638 Diodes
(Blue) 6W+ NUBM44 and (Green) NDG7475 1W. All on regulating switches of course so I can balance out the power differences to make white.

 

[diachi]

Any advice is highly appreciatedd. I am learning as I go with this. Ive been working with lasers for 10 years and have grown slightly, only slightly bored of my laser builds. This is what I have in mind making now https://youtu.be/vrwxUbrYNgA .....This laser is ***Y. But I want to make a more powerful version of it. I plan to use these diodes together with it but I am not sure if they are compatible in beam combining. (Red) Oclaro 700mW 638 Diodes
(Blue) 6W+ NUBM44 and (Green) NDG7475 1W. All on regulating switches of course so I can balance out the power differences to make white.

Ahh sorry, I thought you were aiming for a projector build. Either way, my points still stand

You can combine those diodes, but they won't all have the same beam characteristics without corrective optics.

 

[midnightchime]

Thats what I was worried about, I really have no clue how I would get the beams to be like each other. Could you enlighten me. This project I will be diving very deep into so i want to learn it all. This laser will be my prize possession, that until I can afford to combine 8 NUBM44 diodes together with 2 knife edge arrays and a PBS cube ....Yes I am a mad man lol

 

[Laser Chick]

Please post pictures when you are done. It sounds like an interesting project.

 

[midnightchime]

I certainly will but it wont be for a while. Im still learning and putting together the funds. My last laser i posted on here though was unique and I was hoping to get feed back on it but my post went un replied

 

[diachi]

Thats what I was worried about, I really have no clue how I would get the beams to be like each other. Could you enlighten me. This project I will be diving very deep into so i want to learn it all. This laser will be my prize possession, that until I can afford to combine 8 NUBM44 diodes together with 2 knife edge arrays and a PBS cube ....Yes I am a mad man lol

There are different ways to do it. But basically, different diodes have different beam characteristics. So different dimensions and different divergences on each axis. You need to match the dimensions of the beams and the divergence on each axis so that they all overlap more closely. Either using a pair cylindrical lenses or an anamorphic prism pair and perhaps a beam expander/reducer too.

Some of these videos will give you a bit of an introduction. https://www.youtube.com/user/TechIngredients/videos

There are lots of threads on corrective optics for various diodes both here and on Photonlexicon. I'm be no means an expert on the subject!

 

[rnovitski1980]

I have had good Success working with this company they have been very helpful and reasonable to deal with. Just my findings. Laser Safety Glasses