Using a concave lens to increase divergence - picking the right strength

[Doc]

Could you PLEASE post a new topic about the new Legislation in europe.

Most of us did not know about this but its mendantory information.

Thank you.

Here's the full document.

Note that the chairman is a Mr H. Winkler, I always wondered what Fonzy was up to these days

[norty303]

Thanks very much for the very full and informative response James.
I agree, a thread in its own right would be best for visibility and maximum participation.
Perhaps it is up to the ILDA 'membership' to make it known that they would like some sort of steer if nothing is forthcoming.

[White-Light]

I've only glanced at it because I can't be bothered to read all of the bumph but as I read it (the 1st few lines anyway ), its a workplace directive to protect "workers" not a public display directive so presumably the duty only applies to protecting employees from the radiation, not the audience at large.

I can see ways of overcoming this: 1. Keep all employees outside of the scanning zone (not necessarily practical eg in the case of security staff), or 2. Issue employees with safety equipment so as to protect against the hazard when they enter the scanned zone eg. laser goggles and if necessary clothing that protects the skin.

PS sorry for the thread hijack but expanding beams for safety is kind of related. I do agree some seperation would be nice but its best done by a mod as then posts can be moved.

[Doc]

Issue employees with safety equipment so as to protect against the hazard when they enter the scanned zone eg. laser goggles and if necessary clothing that protects the skin.

Can you imagine the fear that would strike into your audience?

Employees "suiting up" with PPE to venture in to the audience scanning zone!

[White-Light]

Can you imagine the fear that would strike into your audience?

Employees "suiting up" with PPE to venture in to the audience scanning zone!

Its better than not having a show. Don't employees already have to wear ear plugs in nightclubs (or at least be issued with them?).

I also see customers regularly wearing sun glasses in trance audiences. It wouldn't take a huge leap of faith to see a company producing wrap around stylish sunglasses for employees with laser protective lenses in.

[norty303]

Now started a dedicated thread starting with James post over here
http://www.photonlexicon.com/forums/...767#post140767

[aijii]

I'm trying to convert the equation above to a form that allows one to calculate the distance for a given irradiance...

its been almost 10 years since I did maths at school... my head hurts.

anybody care to help ?

[Doc]

I will make this into a spreadsheet when I have time, right now I am having a 5 miunte break from soldering up my interlock boards

[mccarrot]

I just checked, the concave lenses I have are -2,7 This increases the divrigence enough to be at 10MPE for my 500mW at 8 meters distance.

So for small venues its perfect.

I also demonstrated the lenses at the last snowLEM. You would think fat beams would destroy the whole laser effect, but it stays pretty nice to watch.

I think greenalien also got some of these lenses

[aijii]

I will make this into a spreadsheet when I have time, right now I am having a 5 miunte break from soldering up my interlock boards

You mean like this ?

Trying to solve the E = Radiant Flux/Area equation to provide the distance for a given irradiance.. as you'll see in the spreadsheet.. but there is no formula yet..