in need of safe laser and help!

[nicann]

Hello, I just found this forum. I do not work with lasers but attempting a project that would.

My partner are currently working on a new project and we were believing that all lasers were not safe to use near people. We were researching alternatives but laser seems like the way to go. Research on LED didn't seem to help either. I just came across a laser display with lasers pointed on the lawn and kids playing in the light at night. It states in the description that the lasers were safe due to special doppler sensors were used. Anyone familiar with this? Its Friday afternoon and can not call the company and too impatient for Monday. We are trying to attempt to light during the daylight hours also; would that possible? thanks so much!

[buffo]

"Doppler sensors"? Sounds suspicious. Can you provide more details?

Some laser pointers can be eye-safe, but many of them are not. Over-power laser pointers are extremely common, and at least here in the US, enforcement is very lax.

That being said, it is possible to use lasers near people and be safe, but it is neither simple nor cheap. The fact that you want to perform the effect in daylight makes it even more complicated. Without knowing more about what you are trying to do, it's impossible to advise you further.

What, exactly, do you want to accomplish, and what made you think that a laser would be the ideal solution?

Adam

PS: Please fill out your profile information so we know where you are located. This will affect the answers you receive, as the laws differ from one country to another.

[nicann]

Thank so much for the response. Here is the site http://www.corsonart.com/gallery/album48
I would like to give you more details but the project involves a patent. We are in the US. I will try speaking with my partner tomorrow since he is educated in patent applying. All I can say until then is that is a similiar situation of the kids playing in the light at the park but daylight and preferable a different color besides green. I know he is working on the project I believe with I guess incandelents (spelling) lights but the power that is needed and I can not imagine that is would show up in daylight so I have been researching for alternatives. I found that BMW has developed a headlight with three lasers and some deflectors to make a white light but my partner said it was really wide-based and could not make it like a laser. Thanks for your help, it is so appreciated since we have this idea and have been working on figuring it all out. p.s. do you make lasers?

[nicann]

also, safety is very important to us.

[gottaluvlasers]

As Adam stated, it is going to be hard for us to guide you on the safety aspect if we dont know how it will be used (or intended to be used). that being said, In the USA, you also have to deal with the regulations aspect. Laser displays are governed by the FDA/CDRH and "technically" any Laser >5mW in powers which is used in a display type setting requires certain safety features and whats called a "variance" to operate the Laser.

With you stating that you want the display to be visible in the daylight eludes to the fact that the Laser power requirements will need to be of a pretty significant power output (approx. 1 Watt and higher would be a general starting point depending on the type of effect).

Green (although pretty common these days) is your best bet because it is the most visible to our eyes. So, Watt for Watt you can get away with less and have it appear more.

Average power offsets= G/R= 1:3 (1 watt of green = appeared brightness of 3 Watts of red). G/B= 1:2 and B/R= 1:2

In the picture you postes, the effects on the lawn look really cool. Looks like a really interesting project. Also, the green "stripes" do appear to be Laser, however seem to be diverged (spread out) QUITE a bit. this is good becasue it drastically lowers the dangers of the Laser energy. The more the laser power is "spread out" the less dangerous it becomes.

Whatever you may be designing keep in mind- 1) legalities of the CDRH and 2) Safety of the Laser beam(s). Make sure they are at safe distances and as large as can be (technical term for this is W/cm^2)

The stripes of green you posted look to be pretty safe. Without knowing specifics of the Laser system, it would be hard to say for 100% certainty though.

-Marc

[gabe]

Well if its color you want, you can get color, you can get RGB lasers and color mix to make billions of different colors.

You probably could get a defuser along with a luna wheel, put them infront of a projector, and block off all the area that isnt faced towards the ground, and probably get <5mW
But that would be alot of work, possible but would work

[buffo]

The example you provided is intriguing. It appears that the effect would require a good bit more power than the federally-mandated limit of 5 mw, yet it seems hard to believe that a show of that magnitude and duration would be performed illegally. I honestly can't tell from the pictures if the power levels are legal or not, but the picture with the little girl on the grass with the beam striking her skin definitely looks to be in excess of legal limits, based on my personal experience.

That being said, regardless of whether that particular example was legal or not, trying to re-create something similar to that in broad daylight is definitely going to require a lot more power, and that puts you into the legal jurisdiction of the CDRH, which basically says that if you're above Class 3A limits (5 mw), a whole shitload of rules apply. Chief among them is the 3 meter rule: you must keep the beams at least 3 meters above the highest point on the floor where the audience will be.

True, there are exceptions to this rule, and it is technically possible to get approval to send beams into the audience. However, so-called audience-scanning variances are extremely difficult to obtain. Furthermore, based on your description of the effect you want, I don't think you'll be able to achieve sufficient brightness at the lower irradiance levels that would be required.

There might be an option if you decided to spoil the coherence of the laser before creating the image. Example: the Casio slim-green DLP projector uses 24 watts of laser light to create blue and green light for the projection of video images, yet the output is considered eye-safe. But the result isn't going to look anything like the example you provided above.

Note that some higher-end DLP projectors (10,000 lumen and up) can create very thin beams that look similar to lasers - at least for short distances. This might be an option to consider...

Finally, no, I don't build lasers. I have built a few home-made laser projectors for my own private use, but I do not represent a laser manufacturing company. (Though there are a few here on the forum.)

Adam

[gabe]

yeah a projector could make your life WAY Easyer than using a laser, though it lacks the true feeling of a laser

[nicann]

Projector suggestion sounded great to bypass the government regs (i know, i work for them) until I did research on the projector; the specs reads only 2.5 ft projector distance. I wish I could tell you exactly what we are trying for but patent is pending. And just so you know, its not a patent on the laser itself of course just the idea we have. I will pass on your info to him. Thanks so much since we are so not educated in lasers.
First, we need it to luminate for almost two hundred feet. And the straight beam is desired, not the specs one. Check out this project with lasers one by the same artist http://www.corsonart.com/gallery/album46 Really neat. Notice in the fourth pic that people's shadows are not blocking the laser with their hands in the middle but notice the guys towards the outside that their shadows are blocking and so is the guy on the first pic. What you think?
And if we ever accomplish our dream project I will return here to let you know what it is. Or probably be even here sooner with more questions!

[White-Light]

TBH I don't see how it can be classified legally safe in the US meaning of the word (ie not needing an audience scanning variation and not needing to be within MPE) unless less than 5mw or being fat beam because whilst there's no denying the beams are at grass level, what happens if a kid lies down and puts their face on the ground? It seems to me an eye strike would be inevitable unless the lasers are so low that the distance from cheek to eye is more than the height above the ground.

I could see an exemption for people watching from the path but for people potentially lying down in the beams?

Just looking at the bench where the lasers are being emitted from, they appear maybe 6 or 8 inches above the ground minimum. Personally whilst there's no danger to anyone standing or kneeling I certainly would have thought it possible to put yourself in the beams whilst lying.

However, I know little of US laser law so who knows what exemption they may have been able to obtain.