Incoherent light sources – why worry?

Abstract

While most lasers with open beams pose a potential hazard, this is hardly true of most lamps. In fact almost all lamps are safe. However, in recent years there have been concerns raised about light emitting diodes (LEDs) that are rich in blue light. The LED technology employed in modern computer screens also generates a larger fraction of blue light compared to most conventional light sources used for general illumination. The correlated color temperature (CCT) of many displays and inexpensive LED lamps can be relatively high - at least as high as the CCT of cool-white fluorescent lamps. While almost all of these LED “white-light” lamp sources are not considered hazardous by today’s lamp-safety standards, Some installations are of poor design - resulting in significant discomfort glare and employees and consumers may complain. Although the LSO normally is not called on to answer safety questions posed by these types of lamps, some may complain to the LSO and it is useful to understand these new issues. There are basically only two types of sources that are hazardous: (1) open arcs and arc lamps, and (2) short ultraviolet lamps (e.g., sunlamps and germicidal (UV-C) lamps.While most lasers with open beams pose a potential hazard, this is hardly true of most lamps. In fact almost all lamps are safe. However, in recent years there have been concerns raised about light emitting diodes (LEDs) that are rich in blue light. The LED technology employed in modern computer screens also generates a larger fraction of blue light compared to most conventional light sources used for general illumination. The correlated color temperature (CCT) of many displays and inexpensive LED lamps can be relatively high - at least as high as the CCT of cool-white fluorescent lamps. While almost all of these LED “white-light” lamp sources are not considered hazardous by today’s lamp-safety standards, Some installations are of poor design - resulting in significant discomfort glare and employees and consumers may complain. Although the LSO normally is not called on to answer safety questions posed by these types of lamps, some may complain to the LSO and it is useful to understand these new issues. Th...