Differences in risk perception between the fields of laser radiation and conventional incoherent radiation

Abstract

For a given application, a choice can be made in many cases between the use of a laser, a light-emitting diode (LED) and a conventional light source such as an incandescent lamp. This choice is very often influenced by the differences in the safety rules laid down for these different types of light sources. That this is a problem has been underlined by the fact that LEDs were included in the international laser safety standard IEC 825-11. Most of the measurement and classification procedures of this standard were originally drafted for well-collimated laser beams and scarcely applicable to LED sources which usually have much larger apparent source dimensions. This has led to an overclassification and overestimation of the risk. These problems were in part the reason why IEC established a working group (IEC/TC76/WG 9) and entrusted it with the task to draw up a document specifying maximum permissible exposure (MPE) values for incoherent optical radiation as well as reasonable measurement procedures to check compliance with these limit values. A first draft will be distributed for comments in the near future. The MPE values of the future draft document of IEC/TC76/WG 92 are compared with the laser limits and the differences are discussed.For a given application, a choice can be made in many cases between the use of a laser, a light-emitting diode (LED) and a conventional light source such as an incandescent lamp. This choice is very often influenced by the differences in the safety rules laid down for these different types of light sources. That this is a problem has been underlined by the fact that LEDs were included in the international laser safety standard IEC 825-11. Most of the measurement and classification procedures of this standard were originally drafted for well-collimated laser beams and scarcely applicable to LED sources which usually have much larger apparent source dimensions. This has led to an overclassification and overestimation of the risk. These problems were in part the reason why IEC established a working group (IEC/TC76/WG 9) and entrusted it with the task to draw up a document specifying maximum permissible exposure (MPE) values for incoherent optical radiation as well as reasonable measurement procedures to chec...