Yep, scary numbers!try and do some MPE caluations on this, we have the numbers 3,5mm beam, 1mRad 3200mW, 10 meter distance
Even assuming 1ms exposure time, it's still 221.5 times MPE, with an irradiance of 2200mW/cm^2 !!!!
Yep, scary numbers!try and do some MPE caluations on this, we have the numbers 3,5mm beam, 1mRad 3200mW, 10 meter distance
Even assuming 1ms exposure time, it's still 221.5 times MPE, with an irradiance of 2200mW/cm^2 !!!!
Frikkin Lasers
http://www.frikkinlasers.co.uk
You are using Bonetti's defense against me, ah?
I thought it fitting, considering the rocky terrain.
Indeed those are scary MPE measures there.
I often do graphics shows and If I do a beamshow, I do measurements and add a little extra space to it so its always less then more.
It sucks a lot of people dont follow the regulations.
Also about the damaging of someones eyes, a lot of people dont report it if they get it :/ which is sad.
joost is playing a very tricky game, I wont feel sad or defend him when he does get in trouble, he should work on improving his standards and safety measures.
Last edited by White-Light; 04-11-2012 at 11:18. Reason: Typo on figures
Hi,
You are perhaps right when the scanners are turned off with a direct pointing beam in the eyes, but when the scanners work, I can't imagine an exposure of 1ms in the eyes!
If you suppose that the angle of scanning is 40°, sources 100% ON.
So you have an isosceles triangle => 2 rectangle triangle with an angle of 20°
so 2X(opposit/adjacent = tan 20°)
= 7.27 meters of linear scan at 10m
Then you consider that scanners at this angle are not good, 15KPPS. The linear speed of the beam at 10m is about 7.27m * 15000 = 109191m/s
So the exposure duration for your BIG pupil (suppose you have 10mm of diameter and ALL the beam match in it) will last 0.01(m)/109191(m/s) = 10^-7 second !
Yes, you can calculate the risk with a different way, in term of energy (joules) but I'm pretty sure that it is safe.
But you never know how many times the persons eye is exposed. Your calculation is valid when the beam touches your eyes ones, but it have to be safe at every moment of the show, disregarding the scan angle.
No calculated risks! your talking about someone his or her eyes.
Yes thanks, but
10^-7 S =0,1uS
This gives a MPE of 101 mW/cm^2
a laser 3200mW 1mRad @ 10 meter = 2235 mW/cm^2
If you would lower the power to 1445mW you would be scanning at 10xMPE
Or better, maker the divergence higher![]()
MIIKKKLLLL,
I’m sorry, but your assessment rationale is very wrong. You will not achieve exposures in the nanoseconds domain.
That’s notwithstanding the fact that about 25s into the video, finger-beam type effects are being put into the audience. So your assessment is also flawed in that it relates to a completely different type of laser effect. As Norty correctly points out, 1ms exposures are very readily realistic exposures for laser effects that emphasise laser beams by momentarily pausing beam movement. In which case it also matters not how far back an audience member is, (other than the accessible emission decreasing through divergence), for a stationary beam will be stationary throughout the length of the venue.
Even if the effect is being created by pausing for shorter durations, it will likely be creating more potential hits, and once again, 1ms is a sensible figure to use, even if you are taking into consideration the new way (TOTP Method) of MPE assessment.
Laser Safety
https://www.lvroptical.com
https://www.facebook.com/LaserSafety
- Laser Show Safety Training & Audience Scanning Workshops.
- Effects Assessment, and Realtime MPE Measurement
- Pangolin PASS System Integrator
I think this video is pretty typical for Joost RGB laserverkoop practices.
A typical response would be: "No, I don't have any formal education in pyrotechnics, No, I did not take any of the basic safety measures, I ignored the intended use of the devices. But..... In the end I did not set my showroom ablaze, so what are you bitchin' about ?"
Offtopic: What is it with these flamethrowers anyway? They seem to be designed to tip-overLet's hope they come equipped with a tilt switch.
Last edited by -bart-; 04-12-2012 at 01:14.
I think there's more to be gained by educating him than blasting him. Lets hop Maurice can get through to him at the NL Lem and hope he'll finally take a safety course as a result.
The fact that his own eyes hurt after his show above is quite concerning - obviously eye strain as the retinas don't have nerves, but I'd definitely be off to the optician for some retinal photography in his position.