Pulse of light
Light ripple (light flicker), along with the spectral distribution of illumination and its intensity, is one of the factors that affect visual comfort when lighting a workstation. Lighting ripple is rapid, periodic changes in light intensity. Under typical conditions, most people are unable to see light ripple at frequencies above 80 Hz, which is considered the limiting frequency for LED lighting.
Long-term light ripple is the reason for visual discomfort at work. It can cause headaches, migraines, and trigger epileptic seizures. In industrial environments, it can lead to accidents involving people, as the stroboscopic effect caused by the light ripple leads to a distorted perception of the speed of rotating objects, such as machine parts. The ripple is highly undesirable in sports venues, concerts, where high-quality movie cameras are used, often with fast-frame capability (60 frames/second and above), when the effect of changing light intensity becomes apparent. Peripheral vision is more sensitive to the effect of ripple, which, in a vehicle driver's situation, can disrupt the driver's concentration and redirect attention to the light source, thus creating a traffic safety hazard.
The rapid development of LED-based lighting technology has made this issue increasingly important due to the very fast response time of this type of light source at the level of several dozen, tens of ns.