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2. A Review of Contemporary Issues With Temporal Light Modulation of Lighting Systems

Author

Martinsons, Christophe, Nachtrieb, Robert, Gaines, James, Wolfman, Howard, Vollers, Jonathan, and Zissis, Georges

Abstract

Temporal light modulation (TLM) is defined as a temporal change in luminous or color quantities of a light source, resulting from fluctuations of the power supply. Research studies published during the past decade helped define new metrics describing well-known visual effects of TLM such as flicker and the stroboscopic effect. Other visual artifacts induced by TLM such as the phantom array effect are still under investigation to better understand their occurrence and visibility, especially when viewing modern types of LED modules and power supplies, used for instance in automotive lighting and in color-tunable decorative or entertainment lighting. With the advent of solid-state lighting, high levels of temporal light modulation and new types of waveforms exhibited by some LED lamps and luminaires have generated concerns among users and regulators, thereby motivating the establishment of new research, metrics, and standards. Limits have been set in regulations to protect people from undesirable effects. Below these limits, TLM can be used as a useful optical signature to facilitate remote sensing measurements of lighting systems and their obtrusive light components by lock-in detection techniques.

Published
2024
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3. Photobiological Safety

Author

Martinsons, Christophe, Karlicek, Robert, editor, Sun, Ching-Cherng, editor, Zissis, Georges, editor, and Ma, Ruiqing, editor

Published
2017
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5. Dependence of Temporal Frequency and Chromaticity on the Visibility of the Phantom Array Effect

Author

Kong, Xiangzhen, Vogels, Rens, Martinsons, Christophe, Tengelin, Maria Nilsson, Heynderickx, Ingrid E.J., Kong, Xiangzhen, Vogels, Rens, Martinsons, Christophe, Tengelin, Maria Nilsson, and Heynderickx, Ingrid E.J.

Abstract

The effect of both temporal frequency and chromaticity on the visibility of the phantom array effect has been reported in literature. However, how the visibility changes with the temporal frequency is not consistently answered yet and, therefore, needs additional measurements. As for the effect of chromaticity, literature describes studies with different luminaires (i.e., with different chromaticities and peak wavelengths) and settings (i.e., different intensities and viewing geometry); as a consequence, it is challenging to compare these results directly. Therefore, we investigate the effect of temporal frequency on the visibility of the phantom array effect again, but with a special interest in how the peak frequency changes with chromaticity. The results of our experiment show a bandpass-shaped sensitivity function for the phantom array effect with a peak at 600 Hz, without significant change as a function of the chromaticities used in our experiment. However, the peak sensitivity value is found to be higher with red light than with green and white light.

Published
2023

6. Review of Parameters Measured to Characterize Classrooms’ Indoor Environmental Quality

Author

Tran, Minh Tien, Wei, Wenjuan, Dassonville, Claire, Martinsons, Christophe, Ducruet, Pascal, Mandin, Corinne, Héquet, Valérie, Wargocki, Pawel, Tran, Minh Tien, Wei, Wenjuan, Dassonville, Claire, Martinsons, Christophe, Ducruet, Pascal, Mandin, Corinne, Héquet, Valérie, and Wargocki, Pawel

Abstract

As attention to indoor environmental quality (IEQ) grows, a systematic strategy for assessing IEQ in schools needs to be developed. For this purpose, this paper presents a summary of parameters measured in school classrooms to characterize the quality of thermal, acoustic, and visual environments and indoor air quality (IAQ). The summary is based on a review of published literature reporting measurements in schools in Europe and North America in the past ten years. It also summarizes the measurement protocols and measured concentrations. Eighty-eight papers describing measurements in schools were identified and analyzed. No unique standardized measuring method was used in the reviewed studies and different parameters were measured. The most often measured parameters were those describing the thermal environment and IAQ. The former mainly comprised air temperature and relative humidity. The latter mainly comprised concentrations of carbon dioxide, particulate matter, radon, formaldehyde, and some volatile organic compounds. The measured parameters describing acoustic and visual environments mainly comprised noise level, reverberation time, and illuminance. A few studies reported additional measurements of radiant temperature, operative temperature, and speech intelligibility. Measurement protocols from different studies show inconsistency in sampling duration and location and expressed results. Measured concentrations also show high variation between studies, with some pollutants exceeding the threshold values proposed by local and/or international organizations such as the World Health Organization (WHO). This review provides the reference for developing a rating scheme and protocols for uniform characterization of classroom IEQ.

Published
2023

14. Towards Modelling the Visibility of the Phantom Array Effect

Author

Kong, Xiangzhen, Perz, M., Martinsons, Christophe, Tengelin, Maria Nilsson, Heynderickx, Ingrid E.J., Kong, Xiangzhen, Perz, M., Martinsons, Christophe, Tengelin, Maria Nilsson, and Heynderickx, Ingrid E.J.

Abstract

The phantom array effect is the least studied temporal light artefact (TLA) among the three defined in TR 249:2022 by CIE Technical Committee 1-83 “Visual Aspects of Time-Modulated Lighting Systems.” Models that predict the visibility of both flicker and the stroboscopic effect have been detailed by the CIE and the IEC. When it comes to the phantom array effect, its visibility in real-life situations is most often described as ‘in an otherwise dark environment’, during ‘night driving conditions’, and from a ‘backlight of a car at night’. Thus, almost all laboratory investigations on the phantom array effect adopted experimental conditions with bright light sources in a dark room (i.e., < 1 lx). Multiple psychophysical investigations have studied the phenomenon qualitatively or quantitatively. Variables that have been employed in these studies can be categorized as: 1) individually related characteristics: the age and gender of the observer, and maybe also the saccade speed (i.e., variations around the average speed determined by the size of the saccade amplitude); 2) characteristics of the light modulation: the time-averaged luminance/illuminance for direct/indirect viewing conditions, the temporal frequency, the modulation depth, the shape of the waveform, the duty cycle, and the chromaticity of the light source; and 3) characteristics of the viewing geometry: foveal or peripheral observance, the size of the light source (i.e., the subtended visual angle), the spatial distribution of the light source (i.e., with sharp or smooth edges), the saccade amplitude (which usually is fixed in an experimental setting), and the relative motion of the light source to the observer. Some of these studies measured the visibility of the phantom array effect, but others asked the observers to rate the noticeability and/or annoyance of the phantom array effect. The results of all these investigations can be summarized as follows. The visibility of the artefact did not dep

Published
2022

16. Optical Lock-in Spectrometry Reveals Useful Spectral Features of Temporal Light Modulation in Several Light Source Technologies.

Author

Martinsons, Christophe, Picard, Nicolas, and Carré, Samuel

Subjects
OPTICAL modulation, LIGHT sources, COLORIMETRY, FLUORESCENT lamps, INCANDESCENT lamps
Abstract

This paper presents a study of the spectral characteristics of temporal light modulation in several technologies of lighting products. An optical lock-in spectrometer was designed for this purpose and integrated in a spectral radiant flux measurement facility. It was applied to incandescent and fluorescent lamps, as well as lamps based on white phosphor-converted LEDs and tunable RGB LEDs. The results are well correlated with the light emission processes of each technology. For incandescent lamps, the spectral modulation follows a 1/λ relationship in agreement with the blackbody radiation laws. Measurements performed on halophosphate and tri-phosphor tubes agree well with published data. The modulation and phase spectra of fluorescent lamps reveal a variable modulation rate across the visible range, directly related to the fluorescence lifetimes of the different luminophores, which were estimated from our data using a model of single exponential decay.The spectral modulation of white phosphor-converted LED lamps is nearly constant across the visible spectrum, demonstrating that their color parameters can be assessed from the lock-in modulation amplitude spectrum. In the case of tunable RGB LED lamps using PWM, the spectral modulation widely differs from the steady-state spectral distribution and changes with the user settings, confirming the possible occurrence of temporal color artifacts. Optical lock-in spectrometry can be used to improve spectral and color measurements of solid-state lighting, opening new opportunities for laboratory and remote sensing applications. Other foreseeable applications of optical lock-in spectrometry are also presented. [ABSTRACT FROM AUTHOR]

Published
2023
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21. sj-pdf-1-lrt-10.1177_14771535211026322 – Supplemental Material for A method to measure the spectral responsivity of a photometer using optical excitations with arbitrary spectral distributions

Author

Martinsons, Christophe and Hlayhel, Raed

Subjects
FOS: Other engineering and technologies, 111799 Public Health and Health Services not elsewhere classified, FOS: Health sciences, 99999 Engineering not elsewhere classified
Abstract

Supplemental Material, sj-pdf-1-lrt-10.1177_14771535211026322 for A method to measure the spectral responsivity of a photometer using optical excitations with arbitrary spectral distributions by Christophe Martinsons and Raed Hlayhel in Lighting Research & Technology

Published
2021
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24. A Fiber-Optic Array Spectrometer With Parallel Multichannel Optical Lock-in Detection and its Application to in Situ Lighting Measurements

Author

Martinsons, Christophe, Picard, Nicolas, and Carre, Samuel

Abstract

This article describes a new optical spectroscopy instrument achieving lock-in detection in all its spectral output channels in a parallel and simultaneous fashion. It is based on two identical compact array spectrometers working in phase quadrature thanks to optical modulators synchronized with an external reference signal. In the application example, the optical lock-in spectrometer was used to perform spectral irradiance measurements with commercial LED lamps exhibiting temporal light modulation at different frequencies. A remote sensing optical device was designed to measure from a distance the temporal luminous waveform of a specific LED lamp and send it to the reference input of the optical lock-in spectrometer. When the lamps were operating together on top of a large continuous luminous background, the optical lock-in spectrometer successfully retrieved the respective spectral irradiance distributions and color parameters of each lamp, allowing their characterization to be performed independently of the other light sources illuminating the sensor during the measurements.

Published
2023
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25. A method to measure the spectral responsivity of a photometer using optical excitations with arbitrary spectral distributions.

Author

Martinsons, Christophe and Hlayhel, Raed

Subjects
*ACTION spectrum, *MONOCHROMATORS, *BAYES' theorem, *PHOTOMETERS, *LIGHT sources, *INVERSE problems, *LUMINOUS flux
Abstract

The spectral responsivity of a photometer is usually measured using very narrow optical excitations, provided by a monochromator or a tuneable laser. This article describes a technique to measure the spectral responsivity using an arbitrary number of optical excitations having any type of spectral distribution. The problem is formulated as an inverse problem which is solved using a probabilistic approach based on Bayes' theorem. The method requires a prior knowledge of the spectral responsivity, which can be proportional to the standard photopic function, with an uncertainty level related to the spectral match index of the photometer. Using this method, the estimation can be performed from data provided by a simple experimental set-up. The numerical application provides a stable and unique solution to the inverse problem, along with the estimation uncertainties. Using a tuneable LED source, the method was applied to an illuminance measurement head, giving an estimation of its spectral responsivity from 380 to 780 nm with a step of 1 nm. The results were in good agreement with data obtained by a monochromator-based technique. Our measurement had larger uncertainties towards the red and blue limits of the spectrum as the light source provided very little light at these wavelengths. [ABSTRACT FROM AUTHOR]

Published
2022
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26. Quelle est l'évidence montrant que la lumière nocture peux affecter la santé humaine?

Author

Hicks, David, Attia, Dina, Behar-Cohen, Francine, Carré, Samuel, Enouf, Olivier, Falcon, Jack, Gronfier, Claude, Martinsons, Christophe, Metlaine, Arnaud, Tahkamo, Leena, Torriglia, Alicia, Vienot, Françoise, Torriglia, Alicia, Institut des Neurosciences Cellulaires et Intégratives (INCI), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Direction de l'Evaluation des Risques (DER), Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Sorbonne Université (SU), Centre de Recherche des Cordeliers (CRC (UMR_S_1138 / U1138)), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), Centre Scientifique et Technique du Bâtiment (CSTB), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE ), Muséum national d'Histoire naturelle (MNHN), Université Claude Bernard Lyon 1 - Faculté des sciences et technologies (UCBL FST), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Université Paris Descartes - Paris 5 (UPD5), Aalto University, French Agency for Food, Environmental and Occupational Health & Safety [Maisons-Alfort, France], École pratique des hautes études (EPHE)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), and Aalto University [Espoo, Finland]

Subjects
[SDE] Environmental Sciences, MESH: Circadian Clocks, Circadian Cellular Clock, Light, Physiology, Circadian activity, [SDE]Environmental Sciences, Sleep, ComputingMilieux_MISCELLANEOUS, MESH: Light, Melatonin
Abstract

This study was supported by the Agence Nationale de Sécurité Sanitaire de l’Alimentation, de l’Environnement et du Travail.; International audience; no abstract

Published
2020

28. Lisières et Paysages Urbains - Interreg V A France-Suisse 2014.2020

Author

Bailly, Emeline, Finger-Stich, Andréa, Laroche, Sylvie, Fischer, Claude, Defrance, Jérôme, Jolibois, Alexandre, Martinsons, Christophe, Carré, Samuel, Faucheur, Liz, Colline Le Bonniec, Crémel, Laurence, Dubois, Alain, Gegout, Xavier, Gondret, Karine, Huber, Laurent, Mäder, Laure, Martinez, Lucas, Renaud, Ewa, Steffen, Julie, Lebreton, Aline, Chabert, Chloé, Gourbesville, Marie, Groot, Marion, Bogenmann, Claudia, and Pichelin, Hervé

Published
2020
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29. Visual perception under energy-efficient light sources: detection of the stroboscopic effect under low levels of SVM: final report

Author

Veitch, J. A. and Martinsons, Christophe

Subjects
flicker, temporal light modulation, temporal light artefacts, population, solid-state lighting, stroboscopic effect
Abstract

Temporal Light Modulation (TLM) or “flicker” as it is colloquially known can have visual, neurobiological, performance, and cognitive effects on viewers. The International Electrotechnical Commission and the Commission Internationale de l’Eclairage have identified two metrics that may be used to characterize lighting systems’ TLM: PstLM, to predict visible flicker at frequencies below 80 Hz; and SVM, Stroboscopic Visibility Measure, for the higher frequency stroboscopic effect. While scientific development of these metrics and their associated measurement protocols continue, there is a parallel discussion taking place concerning the appropriate levels for these metrics in regulations. The SSL Annex commissioned a study from researchers at the National Research Council of Canada (NRC) and the Centre Scientifique et Technique du Bâtiment (CSTB) in France, to investigate detection rates for the stroboscopic effect in response to commercially-available light emitting diode (LED) light sources characterized using the SVM, and particularly to assess the population variability in this perception among people sensitive to visual stress. The final report on this work provides insight into both stroboscopic visibility and the acceptability of the conditions for the full sample of 85 people and for the more sensitive individuals. The report follows the publication of a peer-reviewed journal article in Lighting Research and Technology.

Published
2019

32. Correspondence: An appraisal of the effects on human health and the environment of using light-emitting diodes

Author

Martinsons, Christophe, primary, Attia, Dina, additional, Behar-Cohen, Francine, additional, Carré, Samuel, additional, Enouf, Olivier, additional, Falcón, Jack, additional, Gronfier, Claude, additional, Hicks, David, additional, Metlaine, Arnaud, additional, Tahkamo, Leena, additional, Torriglia, Alicia, additional, and Viénot, Françoise, additional

Published
2019
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33. Assessment of Personal Occupational Exposure to Radiofrequency Electromagnetic Fields in Libraries and Media Libraries, Using Calibrated On-Body Exposimeters

Author

MASSARDIER-PILONCHERY, Amelie, NERRIERE, Elena, CROIDIEU, Sophie, NDAGIJIMANA, Fabien, GAUDAIRE, Francois, MARTINSONS, Christophe, NOE, Nicolas, HOURS, Martine, Centre Hospitalier Lyon Sud [CHU - HCL] (CHLS), Hospices Civils de Lyon (HCL), Unité Mixte de Recherche Epidémiologique et de Surveillance Transport Travail Environnement (UMRESTTE UMR T9405), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre Scientifique et Technique du Bâtiment (CSTB), Unité Mixte de Recherche Epidémiologique et de Surveillance Transport Travail Environnement (UMRESTTE UMR_T9405), Université de Lyon-Université de Lyon-Université Gustave Eiffel (UNIV GUSTAVE EIFFEL), Université Henri Poincaré - Nancy 1 (UHP), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), centre supérieur technique du bâtiment, and Centre Scientifique et Technique du Bâtiment (CSTB Saint Martin d'Hères)

Subjects
[SDV.EE.SANT]Life Sciences [q-bio]/Ecology, environment/Health, Radio Waves, Communications Media, Wifi, [SPI.NRJ]Engineering Sciences [physics]/Electric power, lcsh:R, lcsh:Medicine, Article, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Electromagnetic Fields, work, radiofrequencies, Occupational Exposure, libraries, Calibration, [PHYS.PHYS.PHYS-MED-PH]Physics [physics]/Physics [physics]/Medical Physics [physics.med-ph], Humans, measurements, Workplace, Cell Phone, Biological Monitoring
Abstract

WOS:000473750500021; International audience; Background and Objectives: With the spread of Wifi networks, safety concerns have arisen, with complaints of somatic disorders, notably in traditional libraries and media libraries. The aim of the present study was to describe the conditions and levels of exposure to radiofrequency electromagnetic fields in the real-life occupational conditions of those working in traditional libraries and media libraries.Methods: Dynamic measurements, using an exposimeter, were taken in 20 radiofrequency bands from 88 to 5850 MHz. The activity of 28 library workers was analyzed on a space-time budget. An audit of exposure sources and static measurements enabled the work-places to be mapped.Results: In seven libraries, 78,858 samples were taken over the 20 radiofrequency bands from 88 to 5850 MHz. Exposure was described for 28 working days. The median total field was 0.071 V/m (10th percentile: 0.022 V/m, 90th percentile: 0.534 V/m) and for Wifi the median field was 0.005 V/m (10th percentile: 0.005 V/m, 90th percentile: 0.028 V/m). Median individual exposure to Wifi frequency waves ranged from 0.005 to 0.040 V/m.Conclusions: Overall, the occupational exposure in this sector was close to the exposure in the general population. Peaks were due to the use of walkie-talkies by security staff. Exposure due to external sources depended on geographic location. Exposure in this occupation is well below the general occupational exposure levels, notably as regards Wifi.

Published
2019
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37. LES PRINCIPAUX RÉSULTATS SCIENTIFIQUES DU DÉMONSTRATEUR SMART ELECTRIC LYON

Author

PHILIBERT, Nicolas, MARTI, Alain, GOUY, Philippe, AGAPOFF, Sergei, ASSEGOND, Christèle, Neïl AYEB, BAUDOT, Clément, BEGUIN, Pascal, BOUCHE, Nicolas, BOZZI, Laurent, BROSSARD, Maximilien, BROSSAUD, Claire, BUI, Florence, CAPELLI, Sonia, CARLOGANU, Sînziana, CARON, Cécile, CARRE, Samuel, CHARPENTIER, Philippe, COUILLAUD, Nicolas, COVALET, Denis, DESTRUEL, Delphine, DUPLESSIS, Bruno, FERRAGE, Aurélie, FIEULAINE, Nicolas, FLACHET, Nicolas, FLAIG, Julien, Jean-Philippe FOUQUET, GALBAT, Mariane, GAT, Mélanie, GHEDIRA-GUEGAN, Chirine, GOTTELAND, Corinne, GRANNEC, Francis, GUIBOURDENCHE, Julien, GUIOT, Thierry, HARADJI, Yvon, JANDON, Mireille, LAMI, Pascale, LEBERT, Alexandra, LESGARDS, Valérie, MARTINEZ, Frédéric, MARTINSONS, Christophe, MATZNER-LOBER, Eric, MILLIEZ, Maya, MOTTE, Florence, PARENT, Raphaël, PERRIN, Sylvie, PEYRAT, Mathilde, POIZAT, Germain, PORCHY-SIMON, Stéphanie, PORET, Céline, PRIOU, Adélaïde, PUEYO, Valérie, REINERT, Christophe, RIEDERER, Peter, ROBIN, Stéphane, ROSSET, Evie, SALEMBIER, Pascal, SOUBIROU, Pierre, STIRER, Christelle, and TOURNAIRE, Olivier

Published
2017
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42. Characterization of compact fluorescent lights RF emissions in the perspective of human exposure

Author

Letertre, Thierry, Azoulay, Alain, Destrez, Alain, Gaudaire, François, Martinsons, Christophe, Supélec Sciences des Systèmes (E3S), Ecole Supérieure d'Electricité - SUPELEC (FRANCE), DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE), centre supérieur technique du bâtiment, and Duchêne, Bernard

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, [SPI.ELEC] Engineering Sciences [physics]/Electromagnetism, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2009

43. Projet d'élaboration d'un protocole de caractérisation des émissions électromagnétiques des lampes fluorescentes compactes à économie d'énergie

Author

Letertre, Thierry, Azoulay, Alain, Destrez, Alain, Gaudaire, François, Martinsons, Christophe, Supélec Sciences des Systèmes (E3S), Ecole Supérieure d'Electricité - SUPELEC (FRANCE), DRE - Département de Recherche en Electromagnétisme, EMG - Département Electromagnétisme - L2S, Laboratoire des signaux et systèmes (L2S), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-SUPELEC-Campus Gif, Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE), centre supérieur technique du bâtiment, and Duchêne, Bernard

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, [SPI.ELEC] Engineering Sciences [physics]/Electromagnetism, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2009

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