A Matter of Position: How luminaire placement modulates the perceptual and neural impact of LED flicker: An EEG Study on Flicker Perception and Cognitive Load
Translated title
A Matter of Position: How luminaire placement modulates the perceptual and neural impact of LED flicker
Author
Bots, Henderika Johanna
Term
4. Term
Education
Publication year
2025
Submitted on
2025-10-17
Pages
62
Abstract
Energy‑efficient LEDs can sometimes produce flicker—very rapid brightness changes that some people notice or find uncomfortable. This often stems from lower‑quality drivers, the electronics that power the LEDs. This thesis asks a practical question for lighting design: does the harm or annoyance from a flickering light depend on where the light is placed? To test this, a 2×2 experiment compared two flicker rates—60 Hz (60 times per second) and 200 Hz—and two positions: general overhead lighting and a task light placed in the participant’s peripheral visual field (side vision). Fifteen participants completed a card‑sorting task under each of the four conditions. The study gathered self‑reports with questionnaires and recorded brain activity using EEG (electroencephalography), focusing on gamma band power, a common EEG measure. Participants reported that 60 Hz flicker was the most disturbing, especially when the light was positioned as task lighting in peripheral vision. However, these reports were not mirrored by EEG gamma band power, which did not show corresponding differences. This gap highlights a mismatch between what people feel and what this physiological measure captured. For human‑centred lighting design, the findings support prioritizing users’ comfort reports over isolated physiological metrics, and they strongly suggest keeping any light with noticeable flicker out of the peripheral visual field.
Energieffektive LED’er kan nogle gange give flimmer—meget hurtige lysstyrkesvingninger, som nogle lægger mærke til eller oplever som ubehag. Det opstår ofte med drivere af lavere kvalitet, altså den elektronik der forsyner LED’erne. Dette speciale stiller et praktisk spørgsmål for lysdesign: afhænger ulemperne ved et flimrende armatur af, hvor det er placeret? For at undersøge det gennemførtes et 2×2‑eksperiment med to flimmerhastigheder—60 Hz (60 gange i sekundet) og 200 Hz—og to placeringer: generel loftsbelysning og arbejdsbelysning placeret i deltagernes perifere synsfelt (sidesyn). Femten deltagere løste en kortsorteringsopgave under hver af de fire betingelser. Oplevelsen blev indsamlet via spørgeskemaer, og hjerneaktivitet blev målt med EEG (elektroencefalografi) med fokus på gamma‑båndstyrke, et almindeligt EEG‑mål. Deltagerne rapporterede, at 60 Hz flimmer var mest generende, især når lyset var placeret som arbejdsbelysning i det perifere synsfelt. Dette blev dog ikke afspejlet i EEG‑målingerne af gamma‑båndstyrke, som ikke viste tilsvarende forskelle. Forskellen peger på et misforhold mellem den oplevede erfaring og det, dette fysiologiske mål fangede. I et menneskecentreret lysdesign taler resultaterne for at prioritere brugernes komfort og rapporterede ubehag over isolerede fysiologiske mål, og de peger stærkt på at undgå armaturer med mærkbart flimmer i det perifere synsfelt.
[This apstract has been rewritten with the help of AI based on the project's original abstract]
Keywords