Beat Flicker – A Temporal Light Artefact due to Multiple Sources of Time Modulated Light

Metrics of temporal light artefacts (TLAs) are tools meant to quantify the magnitude of the impact of temporal modulated light generated by light sources. However, as lighting systems are becoming more and more complex, just assigning a TLA metrics to a light source is not necessarily an easy task. For example, a luminaire containing two drivers operating on slightly different frequencies could generate a light intensity waveform, resulting in some TLA values at one moment, and different TLA values at another moment. In acoustics, the corresponding phenomena would be two tones with slightly different frequencies, giving rise to something called “beats”. The authors of this paper therefore calls the “light”-version of this phenomena beat flicker. The objective of the present work is to draw attention to a challenge that might arise, when assessing temporal modulated light, using tools currently available. The presence of beat flicker could be such a challenge to handle.