Academic literature on the topic 'Light, Effects, on Humans Daylight LED, Lighting Systems'

LED *Shared senior authors. light sources have a discontinuous light spectrum with a prominent ‘blue’ peak between 450 and 470 nm that influences non-image forming responses in humans. We tested an LED lighting solution mimicking a daylight spectrum on visual comfort, circadian physiology, daytime alertness, mood, cognitive performance and sleep. Fifteen young males twice spent 49 hours in the laboratory under a conventional-LED and under a daylight-LED condition in a balanced cross over design flanked by a baseline and a post-light exposure night. Despite different light spectra, the photopic lux and the correlated colour temperature of the lighting were the same for both LEDs. The colour rendering index and the melanopic strength were 25.3% and 21%, respectively, higher for the daylight LED than the conventional LED. The volunteers had better visual comfort, felt more alert and happier in the morning and evening under daylight LED than conventional LED, while the diurnal melatonin profile, psychomotor vigilance and working memory performance were not significantly different. Delta EEG activity (0.75–4.5 Hz) was significantly higher after daylight-LED than conventional-LED exposure during the post-light exposure night. We have evidence that a daylight-LED solution has beneficial effects on visual comfort, daytime alertness, mood and sleep intensity in healthy volunteers.

The article discusses the influence of light pulsation on the physiological state of humans and birds, some aspects of its occurrence, the main characteristics and the alleged role in the deterioration of chickens’ zootechnical indicators under the conditions of using light sources with light flux pulsations of different frequencies. The current state of lighting equipment in poultry farming is characterized by the rapid development of technologies and the active introduction of LED lighting. Having undeniable advantages, LED lighting systems have some technical features that are currently insufficiently studied and can affect the zootechnical indicators of poultry. A clear definition of the threshold values of the characteristics of the pulsation of illumination in the poultry house will make it possible to produce lighting equipment for poultry farming with a safe value of the pulsations of the luminous flux of light sources in their composition. The analysis of numerous literature sources has shown that the influence of light pulsation on the physiological state of humans and zootechnical indicators in birds is associated with a complex effect, depending on such characteristics as the depth and frequency of the pulsation of the light flux of light sources. Despite some differences in the values of the threshold impact of light pulsation, the nature of its impact is similar in humans and birds, which allows us to develop and apply targeted measures to reduce the impact of light pulsation on poultry and the deterioration of its zootechnical indicators.

Artificial light can be used as a management tool to increase milk yield in dairy production. However, little is known about how cows respond to the spectral composition of light. The aim of this study was to investigate how dairy cows respond to artificial achromatic and chromatic lights. A tie-stall barn equipped with light-emitting diode (LED) light fixtures was used to create the controlled experimental light environments. Two experiments were conducted, both using dairy cows of Swedish Red and light mixtures with red, blue or white light. In experiment I, the response to light of increasing intensity on pupil size was evaluated in five pregnant non-lactating cows. In experiment II 16h of achromatic and chromatic daylight in combination with dim, achromatic night light, was tested on pregnant lactating cows during five weeks to observe long term effects on milk production, activity and circadian rhythms. Particular focus was given to possible carry over effects of blue light during the day on activity at night since this has been demonstrated in humans. Increasing intensity of white and blue light affected pupil size (P<0.001), but there was no effect on pupil size with increased intensity of red light. Milk yield was maintained throughout experiment II, and plasma melatonin was higher during dim night light than in daylight for all treatments (P<0.001). In conclusion, our results show that LED fixtures emitting red light driving the ipRGCs indirectly via ML-cones, blue light stimulating both S-cones and ipRGCs directly and a mixture of wavelengths (white light) exert similar effects on milk yield and activity in tied-up dairy cows. This suggests that the spectral composition of LED lighting in a barn is secondary to duration and intensity.

This article draws attention to the shortcomings of modern lighting systems used in greenhouses. Its content focuses on the negative effects of mismatches between the photosynthetic needs of plants and the parameters of artificial light sources. Greenhouse lamps designers often do not have the knowledge of biological cultivation dependencies. Therefore, their cooperation with specialists of plant physiology and gardeners is indispensable. This is important because it can affect the consumer quality of vegetables. Full Text: PDF ReferencesM.Kucharczyk, I.Gąsak, Ecological effects of light pollution , III International Conference on Scientific and Technical TRANSEIA, Krynica Zdrój, Poland, 6-8 December 2017. DirectLink T. H. Goldsmith, What Birds See, Scientific American Inc. (2006), CrossRef E.J. Gerl, M.R. Morris, The Causes and Consequences of Color Vision, Springer Science + Business Media, LLC, 2008. CrossRef K. Jaworski, A. Szmidt-Jaworska, J. Kopcewicz, Two calcium dependent protein kinases are differently regulated by light and have different activity patterns during seedling growth in Pharbitis nil, open access at Springerlink.com, Journal: 10725, Article: 9609, 2011. CrossRef K. Jaworski, A. Pawełek, J. Kopcewicz, A. Szmidt-Jaworska, The calcium-dependent protein kinase (PnCDPK1) is involved in Pharbitis nil flowering, Journal of Plant Physiology 169 p. 1578-1585, 2012. CrossRef A. Szmidt-Jaworska, K. Jaworski, J. Kopcewicz, Effect of light on soluble guanylyl cyclase activity in Pharbitis nil seedlings, Journal of Photochemistry and Photobiology B: Biology 93 p. 9-15, 2008. CrossRef Horticulture Lighting Group, Goniophotometer Test Report of the ELITE ECO lamp CrossRef K. Marra, E. P. LaRochelle, M. S. Chapman, P. J. Hoopes, K. Lukovits, E. V. Maytin, T. Hasan, B. W. Pogue, Comparison of Blue and White Lamp Light with Sunlight for Daylight‐Mediated, 5‐ALA Photodynamic Therapy, in vivo, Wiley Online Library, 16 April 2018 CrossRef M. Gilewski, The Ecological Harmfulness of RGB LED Light, International Conference on Energy, Power, Electrical and Environmental Engineering : EPEEE 2018, DEStech Publications, Wuhan, Hong Kong, September 27-28, 2018. CrossRef K. J. McCree, The Action Spectrum, Absorptance and Quantum Yield of Photosynthesis in Crop Plants, Agricultural Meteorology, Elsevier Publishing Company, 9 p. 191-216 , 1972. CrossRef EconoLux Indastries Ltd., What Light do Plants Need, Hong Kong CrossRef I. Ashdown, Photometry and Photosynthesis: From Photometry to PPFD, SunTracker Technologies Ltd CrossRef OSRAM Opto Semiconductors, Horticulture Lighting with LEDs, OS SSL | NR AW CH, November 2016 CrossRef M. Mottus, M. Sulev, F. Baret, R. Lopez-Lozano, A. Reinart, Photosynthetically Active Radiation: Measurement and Modeling CrossRef Heliospectra AB, Full Flexibility ELIXIA grow ligh CrossRef Heliospectra AB, Full Flexibility ELIXIA grow light CrossRef A. Szmidt-Jaworska1, K. Jaworski1, A. Tretyn, J. Kopcewicz, The involvement of cyclic GMP in the photoperiodic flower induction of Pharbitis nil, J. Plant Physiol. 161. p. 277-284, 2004. CrossRef A. Szmidt-Jaworska, K. Jaworski, J. Kopcewicz, The Involvement of Cyclic ADPR in Photoperiodic Flower Induction of Pharbitis nil, J Plant Growth Regul 25: p. 233-244, 2006. CrossRef A. Szmidt-Jaworska, K. Jaworski, A. Zienkiewicz, M. Lenartowska, J. Kopcewicz, Guanylyl cyclase activity during photoperiodic flower induction in Pharbitis nil, Plant Growth Regul 57: p. 173-184, 2009. CrossRef U.J. Błaszczak, D.A. Aziz, L. Gryko, Influence of the spectral composition of LED lighting system on plants cultivation in a darkroom, Proceedings of SPIE, vol. 10445, (2017) 1-9. CrossRef L. Gryko, U. Blaszczak, A.S. Zajac, Colorimetric characterization of the tunable LED-based light source at the output of the homogenizing rod, Proceedings of SPIE, vol. 10808, 2018. CrossRef I.Fryc, T. Dimitrova-Grekow, An automated system for evaluation of the quality of light sources, 6th IEEE Lighting Conference of the Visegrad Countries : LUMEN V4, Karpacz, September 13-16, 2016. CrossRef J. Kusznier, M. Zajkowski, L. Budzynski, D. Tyniecki, Ring optical mixer for LED with truncated surfaces, Proceedings of SPIE, vol. 10325, 2017. CrossRef W. Wojtkowski, LED Power Supply with Thermal Protection for Automotive Application, 7th Lighting Conference of the Visegrad Countries : LUMEN V4, Třebíč, September 18-20, 2018. CrossRef W. Wojtkowski, Constant Frequency Operation of the Parallel Loaded Resonant DC/DC Converter for Power LED Lighting, International Conference on Energy, Power, Electrical and Environmental Engineering : EPEEE 2018, DEStech Publications, Wuhan, Hong Kong, September 27-28, 2018. CrossRef Pashiardis S, Kalogirou SA and Pelengaris A. Characteristics of Photosynthetic Active Radiation (PAR) Through Statistical Analysis at Larnaca, Cyprus. SM J Biometrics Biostat. 2(2): 1009, 2017. DirectLink R. Inger, J. Bennie, T. W. Davies, K. J. Gaston, Potential Biological and Ecological Effects of Flickering Artificial Light, PLoS One, vol. 9(5) (2014) PMC4038456 CrossRef C. Dong, Y. Fu, G. Liu, H. Liu, "Growth, photosynthetic characteristics, antioxidant capacity and biomass yield and quality of wheat (Triticum aestivum L.) exposed to LED light sources with different spectra combinations", J Agron Crop Sci, vol. 200, p. 219-230, 2014. CrossRef

The article describes the main activities of the International Commission on Illumination in recent years. The most important publications are reflecting recent developments in lighting science and industry, including LED sources and luminaires test methods, fundamental recommendations concerning colorimetry, discomfort caused by glare from luminaires with a non-uniform luminance, as well as intelligent control of lighting systems. Human centric lighting and the non-visual effects of light on humans was highlighted. To promote standardization in the field of horticultural lighting the CIE is in the process of establishing a new JTC. In view of COVID‑19 pandemic outspread the use of germicidal UV radiation is of relevance to reduce both contact spread and airborne transmission of infectious agents. The CIE is responsible for worldwide standardization of the fundamentals, including metrology and vocabulary, as well as lighting education. The CIE considers it important to make digital products including validated calculation tools, apps, databases and machine-readable documents more available for many experts and it takes a step in this direction by provide open access to the individual CIE publications.

This study investigated whether personal relevance influences the affective appraisal of a desktop virtual environment (VE) in simulated darkness. In the real world, darkness often evokes thoughts of vulnerability, threat, and danger, and may automatically precipitate emotional responses consonant with those thoughts (fear of darkness). This influences the affective appraisal of a given environment after dark and the way humans behave in that environment in conditions of low lighting. Desktop VEs are increasingly deployed to study the effects of environmental qualities and (architectural or lighting) interventions on human behaviour and feelings of safety. Their (ecological) validity for these purposes depends critically on their ability to correctly address the user’s cognitive and affective experience. Previous studies with desktop (i.e., non-immersive) VEs found that simulated darkness only slightly affects the user’s behavioral and emotional responses to the represented environment, in contrast to the responses observed for immersive VEs. We hypothesize that the desktop VE scenarios used in previous studies less effectively induced emotional and behavioral responses because they lacked personal relevance. In addition, factors like signs of social presence and relatively high levels of ambient lighting may also have limited these responses. In this study, young female volunteers explored either a daytime or a night-time (low ambient light level) version of a desktop VE representing a deserted (no social presence) prototypical Dutch polder landscape. To enhance the personal relevance of the simulation, a fraction of the participants were led to believe that the virtual exploration tour would prepare them for a follow-up tour through the real world counterpart of the VE. The affective appraisal of the VE and the emotional response of the participants were measured through self-report. The results show that the VE was appraised as slightly less pleasant and more arousing in simulated darkness (compared to a daylight) condition, as expected. However, the fictitious follow-up assignment had no emotional effects and did not influence the affective appraisal of the VE. Further research is required to establish the qualities that may enhance the validity of desktop VEs for both etiological (e.g., the effects of signs of darkness on navigation behaviour and fear of crime) and intervention (e.g., effects of street lighting on feelings of safety) research.

International standard CIE S 026:2018 provides lighting professionals and field researchers in chronobiology with a method to characterize light exposures with respect to non-visual photoreception and responses. This standard defines five spectral sensitivity functions that describe optical radiation for its ability to stimulate each of the five α-opic retinal photoreceptor classes that contribute to the non-visual effects of light in humans via intrinsically-photosensitive retinal ganglion cells (ipRGCs). The CIE also recently published an open-access α-opic toolbox that calculates all the quantities and ratios of the α-opic metrology in the photometric, radiometric and photon systems, based on either a measured (user-defined) spectrum or selected illuminants (A, D65, E, FL11, LED-B3) built into the toolbox. For a wide variety of ecologically-valid conditions, the melanopsin-based photoreception of ipRGCs has been shown to account for the spectral sensitivity of non-visual responses, from shifting the timing of nocturnal sleep and melatonin secretion to regulating steady-state pupil diameter. Recent findings continue to confirm that the photopigment melanopsin also plays a role in visual responses, and that melanopsin-based photoreception may have a significant influence on brightness perception and aspects of spatial vision. Although knowledge concerning the extent to which rods and cones interact with ipRGCs in driving non-visual effects is still growing, a CIE position statement recently used melanopic equivalent daylight (D65) illuminance in preliminary guidance on applying “proper light at the proper time” to manipulate non-visual responses. Further guidance on this approach is awaited from the participants of the 2nd International Workshop on Circadian and Neurophysiological Photometry (in Manchester, August 2019). The new α-opic metrology of CIE S 026 enables traceable measurements and a formal, quantitative specification of personal light exposures, photic interventions and lighting designs. Here, we apply this metrology to everyday light sources including a natural daylight time series, a range of LED lighting products and, using the toobox, to a smartphone display screen. This collection of examples suggests ways in which variations in the melanopic content of light over the day can be adopted in strategies that use light to support human health and well-being.

Mehr als 90% eines Tages verbringen Europäer im Durchschnitt innerhalb von Gebäuden. In der Vergangenheit orientierten sich die Empfehlungen für Innenbeleuchtung überwiegend an den visuellen Anforderungen. Wenn man aber von einer evolutionären Anpassung des Menschen an natürliche Lichtbedingungen ausgeht, müsste sich die Nachbildung von natürlichen Lichtbedingungen, die über die visuellen Anforderungen hinausgehen, in der künstlichen Raumbeleuchtung positiv auf Befinden und Leistung auswirken. Diese Arbeit geht der Frage „Welche Eigenschaften des natürlichen Lichts sind wichtig und sollten bei der Innenbeleuchtung nachgebildet werden?“ auf den Grund und leistet mit neuen Erkenntnissen zur Lichtwirkung einen Beitrag zur Wissenschaft. Das zentrale Ziel dieser Arbeit ist die Beantwortung der Frage, ob sich eine technisch realisierte Lichtexposition, welche nach Qualität und Dynamik dem natürlichen Tageslicht ähnlicher ist als die heutige Standardbeleuchtung, positiv auf subjektive Befindlichkeiten und die Leistungsfähigkeit auswirkt. Ob und welche Dynamiken des natürlichen Lichts bei der Innenbeleuchtung nachgebildet werden sollten, um optimale Arbeitsbedingungen bei der Wissensarbeit zu schaffen, wird aus grundlegenden Untersuchungen zu dynamischem Licht abgeleitet. Schwerpunkt der Untersuchungen sind ultradiane Lichtwechsel.

Mehr als 90% eines Tages verbringen Europäer im Durchschnitt innerhalb von Gebäuden. In der Vergangenheit orientierten sich die Empfehlungen für Innenbeleuchtung überwiegend an den visuellen Anforderungen. Wenn man aber von einer evolutionären Anpassung des Menschen an natürliche Lichtbedingungen ausgeht, müsste sich die Nachbildung von natürlichen Lichtbedingungen, die über die visuellen Anforderungen hinausgehen, in der künstlichen Raumbeleuchtung positiv auf Befinden und Leistung auswirken. Diese Arbeit geht der Frage „Welche Eigenschaften des natürlichen Lichts sind wichtig und sollten bei der Innenbeleuchtung nachgebildet werden?“ auf den Grund und leistet mit neuen Erkenntnissen zur Lichtwirkung einen Beitrag zur Wissenschaft. Das zentrale Ziel dieser Arbeit ist die Beantwortung der Frage, ob sich eine technisch realisierte Lichtexposition, welche nach Qualität und Dynamik dem natürlichen Tageslicht ähnlicher ist als die heutige Standardbeleuchtung, positiv auf subjektive Befindlichkeiten und die Leistungsfähigkeit auswirkt. Ob und welche Dynamiken des natürlichen Lichts bei der Innenbeleuchtung nachgebildet werden sollten, um optimale Arbeitsbedingungen bei der Wissensarbeit zu schaffen, wird aus grundlegenden Untersuchungen zu dynamischem Licht abgeleitet. Schwerpunkt der Untersuchungen sind ultradiane Lichtwechsel.

Progress in lighting technology comes in waves: As the LED is emerging as the winner from the current wave, the digital transformation is pushing the limits of technical possibilities of lighting once more, as it gives access to more degrees of freedom in lighting. Advances over the last decade have significantly expanded the scope of lighting technology: ‘Intelligent Lighting’ yields several new opportunities. Through the advantageous properties of LEDs electric light will be a carrier for optical wireless communication. It finally will provide its users the lost qualities of a natural dynamic light environment as a surrogate of sunlight with all its stimulating effects, thus a ‘Human Centric Lighting’ addressing the biological needs of a ship’s crew with limited access to daylight, increasing their well-being, health and performance on the job.