The photobiological safety of optical radiation emitted by image projectors, particularly of laser illuminated projectors (LIP), is addressed by the recently published product safety standard IEC 62471-5 [Photobiological Safety of Lamps and Lamp Systems—Part 5: Image Projectors (IEC, 2015)]. According to IEC 62471-5, the accessible emission is determined at a distance of 1 m from the projection lens. A classification framework is used to categorize projectors into risk groups (RG), indicating the degree of risk from potential optical radiation hazards to the eye and skin, ranging from the exempt risk group (RG0) to risk group 3 (RG3). According to IEC 62471-5, the highest classification permitted for consumer products is RG2. In this paper, a risk analysis for exposure to the emission of LIP classified as RG2, at distances less than 1 m is provided. The analysis shows that the risk for retinal injury associated with RG2 LIP or conventional projectors at distances less than 1 m can be considered as very low to negligible.

IEC 60825-1 Edition 3 features a new subclause 4.4 which-provided that several requirements are fulfilled-permits classification of a laser illuminated light source as Class 1 under IEC 60825-1 and classification of the accessible light emission under the IEC 62471 series (Photobiological safety of lamps and lamp systems). The practical application of the requirements of this subclause is discussed, as well as the recent IEC Interpretation Sheet on subclause 4.4. Caveat The authors were actively involved in the development of subclause 4.4 of IEC 60825-1 Edition 3.0 as well as in the development of IEC 62471-5 Edition 1. It is emphasised that the content of these proceedings reflects the personal view of the authors and shall not be seen as official or generally accepted interpretation for the application of subclause 4.4 of IEC 60825-1.

Accordingto the upcoming international photobiological safety standard for image projectors IEC 62471-5, the risk group of the projector is to be determined at a distance of 1 meter from the projector closest point of human access.This document discusses biophysical data for Risk Group 2 (RG2) projectors which support the reference distance of 1 meter and in addition a risk analysis for exposure distances closer than 1 meter is provided. The analysis is based on the two main relevant parameters: the safety margin between injury threshold and emission limit, and the diameter of the pupil of the eye. The injury threshold for retinal thermal injury can be modeled well with the Seibersdorf Laboratories Injury Model and was calculated for the relevant wavelength distributions, retinal image sizes and exposure durations. The eye pupil diameter will be accounted for by data identified in the literature, considering that in order to accommodate to an apparent source at close distances, the pupil can be assumed to constrict due to the near triad of accommodation.It is shown that the risk for retinal thermal injury from image projectors classified as RG2 under IEC 62471-5 can be considered as low to negligible.

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