As modern energy-efficient lighting technologies, including LED-based solid-state lighting (SSL), proliferate in our environment, awareness of their impact on biology and even technology evolves as well. LED lighting’s rapid development and assimilation, often without clear standards, may result in lighting flicker with adverse effects. Many organizations, including international standards bodies and regulatory agencies, and industry professionals across many disciplines are working hard to measure, understand, and appropriately regulate flicker.
MIKOŁAJ PRZYBYŁA and PAWEŁ CZARNECKI explain the current state of flicker metrics and suggest best practices for taking measurements and characterizing the phenomenon.
Published on:April 23, 2018 in LEDs MAGAZINE
Flicker is not a new concept, but let’s examine modern considerations of this lighting phenomenon. A full understanding will allow professionals working across the full range of the industry — from product development to lighting specification and design — to achieve the best results with SSL.
FLICKER — OLD PHENOMENON, NEW TWIST
Light flicker is the periodic, fast change of photometric quantities of a light source or lamp. It is the net result of the lighting system design and implementation, including line power characteristics, ballasts and/or drivers, settings, and the light emitters themselves.
Flicker has existed since the invention of AC (alternating current) powered light sources. Changes in the supply power phase produce a correspondingly fast, periodic change of the emitted optical radiation and resultant lighting intensity or luminance. Traditional incandescent lighting systems are affected, but with less-visible results because the filament responds to power changes comparatively slowly. Other light sources, e.g., fluorescent tube or other discharge lamps, have rapid response times so changes are more apparent to an observer. Good design and modern electronic ballasts with higher frequencies can mitigate flicker with these sources.
LED light sources are a different story. Based on semiconductors, they respond rapidly to power changes, and commonly used power systems and drivers can create excessive flicker. As lighting manufacturers deliver designs intended to balance energy efficiency with biometric considerations, the best compromises between cost, efficiency, and flicker level are not always readily apparent. A better understanding of flicker effects, causes, and measurement leads to improved products, efficiencies, and the health of users… Continue reading on LEDs MAGAZINE