Safety assessments of visible scanned laser beams

A number of laser applications result in either intentional or unintentional exposure of the eyes of people to scanned laser beams. The largest number of people potentially at risk from such exposure is in the entertainment industry where intentional scanning of the audience may form part of the visual effect. Data from measurements of scanned beams from laser display systems are presented. The results suggest that internationally recognised maximum permissible exposure levels can be exceeded. The influence of scan rate on hazard is discussed. It is shown that in the majority of measurement situations it is necessary to use instruments which are capable of resolving individual pulses rather than thermal instruments responding only to the average power.