scholarly journals Artificial light sources as light pollutant of humans melatonin suppression

2019 ◽  
Vol 11 (3) ◽  
pp. 78 ◽  
Author(s):  
Piotr Jakubowski
Keyword(s):  
Blue Light ◽  
Power Distribution ◽  
Optical Radiation ◽  
Spectral Power ◽  
International Workshop ◽  
Action Spectrum ◽  
Legal Aspects ◽  
Light Sources ◽  
Research Technology ◽  
Melatonin Suppression

Blue light emitted by LEDs might influence on natural biological rhythm of human being, what can be considered as environment pollution. In this paper the effect of the latest commercially available LEDs on melatonin suppression index (MSI) was analyzed. Research was done based on spectral power distribution of given LED (SPD) and melatonin suppression function in reference to melatonin suppression under daylight (illuminant D65). Results of calculations shows strong correlation between CCT and MSI, however MSI factor might vary for different LEDs with same CCT. Full Text: PDF ReferencesC. C. Sun, et al., Packaging efficiency in phosphor-converted white LEDs and its impact to the limit of luminous efficacy, Journal of Solid State Lighting, 1:19, (2014). CrossRef M. S. Rea, M. G. Figueiro, J. D. Bullough, "Circadian photobiology: An emerging framework for lighting practice and research", Light Research Technology Vol. 34(3), (2002). CrossRef I. Fryc, P. Jakubowski, K. Kołacz, Analysis of optical radiation parameters of compact discharge HID lamps and LED COB modules used for illuminating shop windows, Przeglad Elektrotechniczny, R. 93, No. 11, (2017). CrossRef G. C. Brainard, J. P. Hanifin, J.M. Greeson, B. Byrne, E. Gerner, D. D. Rollang, "Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor", Journal of Neuroscience vol. 21, (2001). CrossRef K. Thapan, J. Arendt, D. J. Skene, "An action spectrum for melatonin supression: evidence for a novel non-rod, non-cone photoreceptor system in humans," Journal of Physiology vol. 535, (2001). CrossRef I. Fryc, J. Fryc, P. Jakubowski, K. A. Wąsowski, Technical, medical and legal aspects of domestic light sources photobiological safety, Przeglad Elektrotechniczny, R. 93, No. 3, (2017). CrossRef J. Enzi et. al, A "Melanopic" Spectral Efficiency Function Predicts the Sensitivity of Melanopsin Photoreceptors to Polychromatic Lights Journal of biological rhytms, Vol. 26 No. 4, (2011). CrossRef M. Aube, J. Roby J, M. Kocifaj, Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression, Photosynthesis, and Star Visibility. PLOS ONE, Vol. 8, (2013). CrossRef P. Jakubowski, I. Fryc, Metrological requirements for measurements of circadian radiation, Optica Applicata, Vol. 48 Issue 4, (2018). CrossRef P. Jakubowski, I. Fryc, Measurement methods of optical radiation in circadian active range, Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej, nr 54 (2017). DirectLink P. Jakubowski, Comparative analysis of light parameters of LEDs and OLEDs in context of blue light emission, Polish Journal for Sustainable Development 21 (2), (2017). CrossRef CIE TN003:2015, "Report on the First International Workshop on Circadian and neurophysiological Photometry", (2015). DirectLink

Methodology for Measurement of the Blue Light Hazard of Light-Emitting Diodes with Imaging Luminance Meter

2013 ◽  
Vol 455 ◽  
pp. 460-465
Author(s):  
Jie Liu ◽  
Xiao Bo Zhuang ◽  
Hua Yao ◽  
Shan Duan Zhang
Keyword(s):  
Blue Light ◽  
Power Distribution ◽  
Spectral Power ◽  
Color Temperature ◽  
Light Sources ◽  
Weighted Function ◽  
Light Emitting ◽  
Spectral Power Distribution ◽  
Fluorescent Lamps ◽  
Compact Fluorescent Lamps

Most of the measurement methods for blue light hazard (BLH) evaluation are based on radiance, which are too complex and hard to find out the highest radiance. We proposed a methodology for measurement of BLH with imaging luminance meter. We measured the relative spectral power distribution with a spectrometer and the maximum luminance with an imaging luminance meter for LEDs and compact fluorescent lamps, and calculated the BLH weighted radiance. The BLH efficacy and the upper limit of luminance with blue light safe of various light sources were also calculated on the basis of the BLH weighted function. The results show absolute blue light safe can be obtained if the luminance is limited to 100 kcd m2 for color temperature lower than 6500 K. LEDs with high color temperature, especially those without diffused window, have potential risk of BLH. Our method can be used in online measurement of the BLH of LEDs.

scholarly journals Spectral Tuning of White Light Allows for Strong Reduction in Melatonin Suppression without Changing Illumination Level or Color Temperature

2018 ◽  
Vol 33 (4) ◽  
pp. 420-431 ◽  
Author(s):  
Jan L. Souman ◽  
Tobias Borra ◽  
Iris de Goijer ◽  
Luc J. M. Schlangen ◽  
Björn N. S. Vlaskamp ◽  
...  
Keyword(s):  
White Light ◽  
High Power ◽  
Spectral Power ◽  
Monochromatic Light ◽  
Action Spectrum ◽  
Color Temperature ◽  
Light Spectrum ◽  
Melatonin Suppression ◽  
Dim Light ◽  
Melatonin Production

Studies with monochromatic light stimuli have shown that the action spectrum for melatonin suppression exhibits its highest sensitivity at short wavelengths, around 460 to 480 nm. Other studies have demonstrated that filtering out the short wavelengths from white light reduces melatonin suppression. However, this filtering of short wavelengths was generally confounded with reduced light intensity and/or changes in color temperature. Moreover, it changed the appearance from white light to yellow/orange, rendering it unusable for many practical applications. Here, we show that selectively tuning a polychromatic white light spectrum, compensating for the reduction in spectral power between 450 and 500 nm by enhancing power at even shorter wavelengths, can produce greatly different effects on melatonin production, without changes in illuminance or color temperature. On different evenings, 15 participants were exposed to 3 h of white light with either low or high power between 450 and 500 nm, and the effects on salivary melatonin levels and alertness were compared with those during a dim light baseline. Exposure to the spectrum with low power between 450 and 500 nm, but high power at even shorter wavelengths, did not suppress melatonin compared with dim light, despite a large difference in illuminance (175 vs. <5 lux). In contrast, exposure to the spectrum with high power between 450 and 500 nm (also 175 lux) resulted in almost 50% melatonin suppression. For alertness, no significant differences between the 3 conditions were observed. These results open up new opportunities for lighting applications that allow for the use of electrical lighting without disturbance of melatonin production.

AN OVERVIEW OF THE IMPACT OF STRAY LIGHT FROM COMMERCIAL GREENHOUSES

2021 ◽  
Author(s):  
K. Bertin ◽  
G. Zissis ◽  
G. Salas ◽  
P.M. Raynham ◽  
A. Moutsi ◽  
...  
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Stray Light ◽  
Significant Problem ◽  
Light Sources ◽  
Spectral Power Distribution ◽  
Outdoor Work ◽  
Local Residents ◽  
The Impact ◽  
Current Standards

Stray light from commercial greenhouses is becoming a significant problem causing disruption to wildlife activity and annoyance for local residents. To quantify the amount of stray light from a typical large greenhouse the authors have modelled several lighting installations based on a range of generic horticultural light sources. The impact of the stray light is dependent on the spectral power distribution of the sources employed, the intensity and distribution. Current standards for obtrusive light from outdoor work places do not seem to be suitable when applied to greenhouses.

Circadian stimulus – A computation model with photometric and colorimetric quantities

2019 ◽  
Vol 52 (6) ◽  
pp. 751-762
Author(s):  
W Truong ◽  
V Trinh ◽  
TQ Khanh
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
External Validation ◽  
Circadian System ◽  
Model Fit ◽  
Light Sources ◽  
Computation Model ◽  
Internal Validation ◽  
Spectral Power Distribution ◽  
Chromaticity Coordinate

The circadian stimulus is an important, validated and updated metric that describes the invisible influences of light on the human circadian system explicitly and scientifically. However, an absolute spectral power distribution must be supplied for its computation, which is only measurable by an expensive and complicated spectrometer. This paper proposes an alternative circadian stimulus computation model that is identified as the function CS(z, Ev) for white light sources based on the most common and simplest parameters of illuminance Ev in lux and the chromaticity coordinate z. These parameters are well known and widely used in both colour science and lighting technology. In order to prove the accuracy and availability of the model, an internal validation was performed with the adapted method repeating split data to check the goodness of the model fit. The fitted model achieved a maximum residual of 0.058 in the circadian stimulus quantity (R2 = 0.998). An external validation with the maximum residual of 0.030 (R2 = 0.999) provided stronger evidence for the usability of the model in applications.

scholarly journals Optimising the illumination spectrum for enhancing tissue visualisation

2017 ◽  
Vol 51 (1) ◽  
pp. 99-110 ◽  
Author(s):  
J Shen ◽  
S Chang ◽  
H Wang ◽  
Z Zheng
Keyword(s):  
Biological Tissue ◽  
Power Distribution ◽  
Spectral Reflectance ◽  
Evaluation Method ◽  
Multispectral Imaging ◽  
Spectral Power ◽  
Light Sources ◽  
White Led ◽  
Spectral Power Distribution ◽  
Visual Entropy

In operations, light reflected from biological tissue can be used for disease detection. In this paper, we used a visual entropy evaluation method to design the optimal illuminant to improve colour discriminability of biological tissue. The optimal spectral power distribution of the illuminant was obtained by maximising the visual entropy value of sample tissue based on the human visual system. In the experiment, multispectral imaging was used to measure the spectral reflectance of the tissue and colour clustering was conducted to extract its colour features. To verify the effectiveness of this method, simulated tissue images under illuminations with optimised spectral power distributions were compared with those under other light sources such as the standard illuminant D65 and white LED light sources. Results show that the sample under optimised illumination has a higher visual entropy value with better perceptual visibility.

scholarly journals Spectral properties of smart LED lamps

2020 ◽  
Vol 12 (1) ◽  
pp. 16
Author(s):  
Jacek Kusznier ◽  
Wojciech Wojtkowski
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Electrical Engineering ◽  
Climatic Conditions ◽  
Intraocular Lenses ◽  
Automated System ◽  
Integrating Sphere ◽  
Light Sources ◽  
Spectral Power Distribution

Intelligent LED lamps are most often used in intelligent lighting installations. They frequently use one of two different ways to obtain white light. The first is the mixing of monochrome lights R, G and B. The second way is to mix the light of the blue diode with the yellow phosphor radiation. Adjusting the luminous flux in RGBW LED lamps causes greater changes in the position of the chromaticity point than in the case of CW WW LED lamps. In the case of big changes, this can lead to a visible change in the perceived color. Full Text: PDF References:https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html [DirectLink]https://dateandtime.info/pl [DirectLink]J. Kusznier and W. Wojtkowski, "Impact of climatic conditions on PV panels operation in a photovoltaic power plant," IEEE, 2019 15th Selected Issues of Electrical Engineering and Electronics (WZEE), Zakopane, Poland, 2019, pp. 1-6 [CrossRef]J. Kusznier and W. Wojtkowski, "Impact of climatic conditions and solar exposure on the aging of PV panels," IEEE, 2019 15th Selected Issues of Electrical Engineering and Electronics (WZEE), Zakopane, Poland, 2019, pp. 1-6 [CrossRef]https://www.weatheronline.pl/weather/ [CrossRef]L.T. Sharpe, A. Jagla, W. Jägle, "A luminous efficiency function, V*(λ), for daylight adaptation", J. Vision 5(11), 948 (2012) [CrossRef]http://www.ee.co.za/article/integrating-sphere-data-sincere.html [DirectLink]Simunovic M. P., "On Seeing Yellow The Case for, and Against, Short-Wavelength Light-Absorbing Intraocular Lenses", Archives of Ophthalmology, vol. 130, no. 7, pp. 919-926, 2012 [CrossRef]I. Fryc, "Important parameters of multichannel spectroradiometer", Przeglad Elektrotechniczny R. 88(4a), pp. 230-231 (2012) [DirectLink]I. Fryc, "Measurement techniques of optical LEDs properties performed with compliance conformity with CIE 127:2007 standard", Przeglad Elektrotechniczny R. 85(11), pp. 317-319 (2009) [CrossRef]J. Kowalska, I. Fryc, "Colour rendition quality of typical fluorescent lamps determined by CIE Colour Fidelity Index and Colour Rendering Index", Przeglad Elektrotechniczny R. 95(7), pp. 94-97 (2019) [CrossRef]M. Gilewski, L. Gryko, A. Zajac, "Digital controlling system to the set of high power LEDs", Proc. of SPIE, 8902, 89021D, 2013 [CrossRef]M. Gilewski, "The ecological hazard of artificial lighting in greenhouses" Photonics Letters of Poland, vol. 11 Issue: 3 Pages: 87-89, 2019 [CrossRef]I. Fryc and T. Dimitrova-Grekow, "An automated system for evaluation of the quality of light sources," 2016 IEEE Lighting Conference of the Visegrad Countries (Lumen V4), Karpacz, 2016, pp. 1-4. [CrossRef]I. Fryc, "The spectral power distribution of LED driven by square shape pulses", Przeglad Elektrotechniczny R. 88(6), pp. 131-133 (2012) [DirectLink]I. Fryc, "LED's spectral power distribution under different condition of operating temperature and driving current", Przeglad Elektrotechniczny R. 86(10), pp. 187-189 (2010) [DirectLink]J. Kusznier, "Changes in the Spectral Power Distribution of Light Sources for Smart Lighting," IEEE, 2018 14th Selected Issues of Electrical Engineering and Electronics (WZEE), Szczecin, Poland, 2018, pp. 1-5 [CrossRef]

scholarly journals How to Report Light Exposure in Human Chronobiology and Sleep Research Experiments

2019 ◽  
Vol 1 (3) ◽  
pp. 280-289 ◽  
Author(s):  
Manuel Spitschan ◽  
Oliver Stefani ◽  
Peter Blattner ◽  
Claude Gronfier ◽  
Steven Lockley ◽  
...  
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Light Exposure ◽  
Action Spectrum ◽  
Point Of View ◽  
Reporting Guidelines ◽  
Visual Responses ◽  
Sleep Research ◽  
Reporting Scheme ◽  
Spectral Power Distribution

Exposure to light has short- and long-term impacts on non-visual responses in humans. While many aspects related to non-visual light sensitivity have been characterised (such as the action spectrum for melatonin suppression), much remains to be elucidated. Here, we provide a set of minimum reporting guidelines for reporting the stimulus conditions involving light as an intervention in chronobiology, sleep research and environmental psychology experiments. Corresponding to the current state-of-the-art knowledge (June 2019), these are (i) measure and report the spectral power distribution of the acute stimulus from the observer’s point of view; (ii) measure and report the spectral power distribution of the background light environment from the observer’s point of view; (iii), make spectra available in tabulated form, (iv) report α-opic (ir)radiances and illuminance; (v) describe the timing properties of stimulus (duration and pattern); (vi) describe the spatial properties of stimulus (spatial arrangement and extent), and (vii) report measurement conditions and equipment. We supplement the minimum reporting guidelines with optional reporting suggestions and discuss limitations of the reporting scheme.

scholarly journals Analysis and Simulation of the Illumination Optics of Rigid Medical Endoscopes

2018 ◽  
Vol 4 (1) ◽  
pp. 169-172 ◽  
Author(s):  
Alexander Gaertner ◽  
Paola Belloni
Keyword(s):  
Simulation Model ◽  
Power Distribution ◽  
Spectral Power ◽  
Integrating Sphere ◽  
Light Sources ◽  
Optimization Approach ◽  
Medical Endoscope ◽  
Spectral Power Distribution ◽  
Light Coupling ◽  
External Light Source

AbstractOur work focuses on enhancing the illumination optics of a rigid medical endoscope using optomechanical simulation. We aim on improving the efficiency of the illumination optics to provide more light in the surgeon’s field of view (FOV) and therefore better image quality. We conducted an extensive market analysis and measured several rigid endoscopes and their external light sources in the lighting technology laboratory. Surprisingly, all endoscopes showed a degree of efficiency below 20 %. Our optimization approach is based first on a photometric and colorimetric analysis carried out with an integrating sphere and a goniophotometer. Secondly, the results obtained are implemented in a 3Doptomechanical simulation model developed with the raytracing software LightTools (Synopsis©). In the simulation model both the geometrical components as well as the critical interfaces are examined considering light coupling at boundary surfaces and light transfer within the illumination optics. Moreover, the optimization takes into account spectral power distribution (SPD) and angular light distribution (ALD) of the light provided from the fiberoptic cable connected to an external light source as well as additional interfering factors like gluing, dispersive absorption and total reflection at critical angles.

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