Removing the LED light strobe flicker by proper driver designs

Mao, Zhaoqi; Ge, Lane; Hua, Gary

doi:10.1109/sslchina.2013.7177350

Cited by 6 publications

(2 citation statements)

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“…It appears that the high percent flicker of early LED luminaires [49,51] spurred manufacturers to develop LED lights that are free of flicker. This has been achieved through the implementation of built-in digital drivers to smooth AC cycling and through the use of slow-decay phosphor coatings [52][53][54][55].…”

Section: Discussionmentioning

confidence: 99%

“…Prior to the development of these methods by manufacturers, there were several influential publications on the LED flicker problem [49,51]. Other papers explored methods to reduce or eliminate flicker in LED lights [52][53][54][55]. It appears that high-end LED manufacturers put in considerable effort to eliminate flicker in the devices they sell.…”

Section: Why Do Flickering Leds Have the Highest Percent Flicker?mentioning

confidence: 99%

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Exploring the Hidden World of Lighting Flicker with a High-Speed Camera

Elvidge,

Zhizhin,

Pipkin

et al. 2024

Atmosphere

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Alternating current can result in flickering—or pulsing—in the brightness of light emitted by luminaires. Lighting flicker typically occurs in the range of 100 to 140 cycles per second (Hz), which is too fast for visual perception by most organisms. However, evidence indicates that many organisms perceive flicker with non-visual photoreceptors present on the retinas. Exposure to flickering lights at night disrupts the circadian rhythm of organisms, leading to symptoms similar to blue light exposure at night. The traditional method for detecting flickering is with a flickermeter held near a single light. In this paper, we explore the use of high-speed camera data in the collection of temporal profiles for groups of luminaires simultaneously at distances ranging from several meters to several kilometers. Temporal profiles are extracted for individual lighting features and the full scene. The identification of luminaire types is based on their spectral signatures. With the camera data, it is possible to identify flickering and non-flickering lights, to determine the flicker frequency, to calculate percent flicker and the flicker index, and to identify groups of lights whose flickers are synchronized. Both flickering and non-flickering luminaires can be found for LED, metal halide, fluorescent, and compact fluorescent lights. To date, flickering has been detected in all of the incandescent, high-pressure sodium, and low-pressure sodium luminaires that we measured. We found that flicker synchronization is often present for lights installed within a single facility and also for strings of streetlights. We also found that flicker exposure can come from the light reflected off of the earth’s surface. Luminaires designed to illuminate large areas often saturate high-speed camera data collection. This saturation can be reduced or eliminated using neutral density filters on the camera. Published experimental data on the impacts of flicker on organisms remains sparse. Many studies have drawn inferences on the impacts of spectral and lighting brightness on organisms without controlling for flicker. Our conclusion is that lighting flicker is a type of light pollution. The use of high-speed camera data makes it easier to include flicker as a variable in studies regarding the impacts of lighting on organisms.

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