One of the main drivers of this revolution is the astonishing rate at which solid state light sources can change their intensity: the response time of a light source to the driving current can be as little as a couple of nanoseconds, almost instantaneously translating the driving current to the luminous output.
A consequence of this is that the modulation of the driving current is directly transferred to a modulation of the luminous output. The modulation of the current can be intended (e.g. to control light intensity and color) or unintended (e.g. from mains power, or resulting from interactions between the driver and dimmer electronics), but one effect of the modulation of luminous output can be changes in visual perception for an observer in a certain environment. These changes are called ‘temporal light artefacts’, or TLAs.
In some specific entertainment applications, a change of perception due to light modulation is desired, but for most everyday applications and activities involving artificial light, the change is detrimental and perceived as negative. At the simplest level, TLAs affect how we judge the quality of light in a space. Going further, the irregularity of light modulation can cause reduced performance, visual fatigue, epileptic seizures, headaches and migraine episodes.
The potential negative impacts of TLAs have prompted lighting manufacturers, lighting application specialists, universities and governments to look for ways to measure the impact and come to a better understanding of the temporal quality aspects of lighting systems and reduce their presence and impact to the minimum. In this context, among the few bodies addressing this subject, the CIE formed Technical Committee (TC) 1-83 ‘Visual Aspects of Time-Modulated Lighting Systems’, and also produced a significant paper: CIE Technical Note 006:2016, ‘Visual Aspects of Time-Modulated Lighting Systems – Definitions and Measurement Models’. Philips Lighting was a primary contributor to this paper.