Fighting Flicker

Abstract

Thanks in part to the rapid emergence of LED lighting, the phenomenon of flicker has been getting increased attention. All conventional light sources modulate luminous flux and intensity to some degree, usually as a consequence of drawing power from AC mains sources. But whereas conventional light sources have somewhat delayed responses to changes in electrical current – which serves to “cushion” them to some degree against flickering – the LED and its driver respond instantly to such changes, which can result in stark fluctuations in light output. And while these fluctuations may not be noticeable to everyone, they can still result in health and task performance problems. Understanding and countering flicker is essential to the success of high-efficiency lighting technology. That’s why the U.S. Department of Energy (DOE) Solid-State Lighting Program conducts flicker research and is supporting a number of industry committees (CIE 1-83: Visual Aspects of Time-Modulated Lighting Systems; CIE 2-89: Measurement of Temporal Light Modulation of Light Sources and Lighting Systems; and the IES Testing Procedures Committee) that are developing flicker standards for measurement, acceptability, and metrics. A wide variety of technical resources on flicker can be found at https://www.energy.gov/eere/ssl/flicker.