The classification of an array of laser or LED sources under the 2001 IEC 60825-1 standard can be a complicated process. It is necessary to determine the most restrictive case for various combinations of source geometry within the array. This paper presents an approach to solving that problem for typical array patterns.
The first step is to determine the combinations of source geometry with the greatest density of sources - one of those is likely to be the most restrictive case. The next step is to calculate the angular subtense for each of these combinations from the source and array dimensions. This value and the data supplied on the source emission can then be used to calculate the allowable power/energy per source for each combination. The geometry of sources within the array with the minimum value of that parameter will be the most restrictive case.