Measurements of the pulse duration, ie the exposure of a theoretical 7 mm diameter ‘eye’ was used to
determine the applicable MPE, generally the reduced single pulse MPE or the MPEtrain, and the maximum
radiant power permitted through this aperture was determined from the pulse duration and number per
scan, or frame. In all cases this radiant power was less than 10 mW. Where the scan rate was low such
that the pulse width reached 0.5 ms, the maximum radiant power was 2.5 mW. This should be compared
with the MPE for a static beam, which would be 1 mW for a single accidental exposure assuming the 0.25
s aversion response.

The conclusion is that the assessment of scanned beams can be greatly simplified by measuring the power
of a static beam through a 7 mm diameter aperture. If this is 1 mW or less then the MPE will not be
exceeded at any position in the scan pattern. This can probably be increased to 2 mW for most scan
patterns (see table 5.4) but any further increase will require significant effort to analyse each scan pattern,
including any failure modes.

In summary:
1. Audience scanning is currently carried out without adequate quantification of the hazard.
2. Analysis of beam effects is complicated for anything other than simple scan patterns.
3. Increasing the speed of a scan pattern does not make it safer.
4. Measurements of scan patterns are not made with appropriate instrumentation. Such measurements
need to determine the duration of exposure for each scan pass the eye, the peak irradiance averaged
over the 7 mm diameter eye, and the number of exposures within a suitable time frame, 0.25 s, say.
5. The analysis of complex scan patterns demonstrates that the maximum power into a 7 mm aperture is
less than a factor of ten above the MPE for a static beam, and often only a factor of two greater.
6. The analysis can be simplified by assessing static beams only.
These conclusions are significant for putting the laser radiation hazard into context with other hazards
which may be present at a laser display.

optix: Dakle, oprezno sa laserima i nikad ne gledati direktno u njih...

zveljko: Ma to su sam price, ja vec godinama radim ozvucenje i rasvetu, nisam cuo ni za jedan takav slucaj, ili sam ja mozda neinformisan...Cisto sumnjam...Postavio sam na preko 100 objekata pred neko desavanje identicne lasere, puta min. 200 ljudi na svakoj zurci, nikada se niko nije zalio, a ti racunaj koliko je to ljudi... : )

Mladi ljudi su oslepeli kada su laserski snopovi namenjeni osvetljenju neba usmereni na publiku.