scholarly journals Blue-Light Levels Emitted from Portable Electronic Devices Compared to Sunlight

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4276
Author(s):  
David Baeza Moyano ◽  
Yolanda Sola ◽  
Roberto Alonso González-Lezcano
Keyword(s):  
Blue Light ◽  
Electronic Device ◽  
Electronic Devices ◽  
Spectral Irradiance ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Spectral Emission ◽  
Visual Effects ◽  
Light Emitting ◽  
Light Levels

Over recent years, a technological revolution has taken place in which conventional lighting has been replaced by light emitting diodes (LEDs). Some studies have shown the possibility that blue light from these artificial sources could have deleterious effects on the retina. Considering that people spend a non-negligible time in front of screens from computers and mobile phones, the eyes receive blue light of different intensities depending on the source. Nevertheless, any study about the visual and non-visual effects of blue light must consider precise measurements taken from actual artificial sources. For this reason, we have analyzed the spectral emission of 10 different electronic devices and weighted them according to the hazard caused by blue light to the eyes, comparing the results with solar radiation simulated with a radiative transfer model. The maximum spectral irradiance of the measured electronic devices at 10 cm from the detector was located between 440 nm and 460 nm. The irradiance for blue light hazard ranged from 0.008 to 0.230 Wm−2 depending on the particular characteristics of each electronic device. In contrast, the solar radiances in the same spectral range are larger both under clear and cloudy conditions.

scholarly journals Comparison of UV-RSS spectral measurements and TUV model runs for clear skies for the May 2003 ARM aerosol intensive observation period

2007 ◽  
Vol 7 (6) ◽  
pp. 17401-17427
Author(s):  
J. J. Michalsky ◽  
P. W. Kiedron
Keyword(s):  
Radiative Transfer ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Spectral Irradiance ◽  
Radiative Transfer Model ◽  
Visible Range ◽  
Transfer Model ◽  
Intensive Observation ◽  
Aerosol Properties ◽  
Observation Period

Abstract. The first successful deployment of the fully-operational ultraviolet rotating shadow-band spectroradiometer occurred during the May 2003 U.S. Department of Energy's Atmospheric Radiation Measurement program's Aerosol Intensive Observation Period. The aerosol properties in the visible range were characterized using redundant measurements with several instruments to determine the column aerosol optical depth, the single scattering albedo, and the asymmetry parameter needed as input for radiative transfer calculations of the downwelling direct normal and diffuse horizontal solar irradiance in clear-sky conditions. The Tropospheric Ultraviolet and Visible (TUV) radiative transfer model developed by Madronich and his colleagues at the U.S. National Center for Atmospheric Research was used for the calculations of the spectral irradiance between 300–360 nm. Since there are few ultraviolet measurements of aerosol properties, most of the input aerosol data for the radiative transfer model are based on the assumption that UV input parameters can be extrapolated from the visible portion of the spectrum. Disagreements between available extraterrestrial spectra, which are discussed briefly, suggested that instead of comparing irradiances that measured and modeled spectral transmittances between 300–360 nm should be compared for the seven cases studied. These cases included low to moderate aerosol loads and low to high solar-zenith angles. A procedure for retrieving single scattering albedo in the ultraviolet based on the comparisons of direct and diffuse transmittance is outlined.

scholarly journals Aerosol Single Scattering Albedo retrieval in the UV range: an application to OMI satellite validation

2010 ◽  
Vol 10 (2) ◽  
pp. 331-340 ◽  
Author(s):  
I. Ialongo ◽  
V. Buchard ◽  
C. Brogniez ◽  
G. R. Casale ◽  
A. M. Siani
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Spectral Irradiance ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Ozone Monitoring Instrument ◽  
Mean Values ◽  
Absorbing Aerosols

Abstract. The aerosol Single Scattering Albedo (SSA) and Absorbing Aerosol Optical Depth (AAOD) at 320.1 nm are derived at Rome site by the comparison between Brewer and modelled spectra. The UVSPEC radiative transfer model is used to calculate the UV irradiances for different SSA values, taking into account as input data total ozone and Aerosol Optical Depth (AOD) obtained from Brewer spectral measurements. The accuracy in determining SSA depends on the aerosol amount and on Solar Zenith Angle (SZA) value: SSA uncertainty increases when AOD and SZA decrease. The monthly mean values of SSA and AAOD during the period January 2005–June 2008 are analysed, showing a monthly and seasonal variability. It is found that the SSA and AAOD averages are 0.80±0.08 and 0.056±0.028, respectively. AAOD retrievals are also used to quantify the error in the Ozone Monitoring Instrument (OMI) surface UV products due to absorbing aerosols, not included in the current OMI UV algorithm. OMI and Brewer UV irradiances at 324.1 nm and Erythemal Dose Rates (EDRs) under clear sky conditions, are compared as a function of AAOD. Three methods are considered to investigate on the applicability of an absorbing aerosol correction on OMI UV data at Rome site. Depending on the correction methodology, the bias value decreases from 18% to 2% for spectral irradiance at 324.1 nm and from 25% to 8% for EDR.

scholarly journals Optical Properties of Polystyrene-ZnO Nanocomposite Scattering Layer to Improve Light Extraction in Organic Light-Emitting Diode

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
G. Nenna ◽  
A. De Girolamo Del Mauro ◽  
E. Massera ◽  
A. Bruno ◽  
T. Fasolino ◽  
...  
Keyword(s):  
Optical Properties ◽  
Light Emitting Diode ◽  
Light Extraction ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Experimental Measurements ◽  
Scattering Layer ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light

In this work, experimental measurements on polystyrene-ZnO nanocomposite scattering films and on organic light-emitting device with and without the scattering layers are presented. The results are also compared with Henyey-Greenstein radiative-transfer model to narrow down the parameters that can be important in the identification of more suitable scattering layers. As a result, an increase of efficiency of about 30% has been obtained that it can be translated in 60% of outcoupled light in respect to the total generated amount.

scholarly journals Towards a Sustainable Indoor Lighting Design: Effects of Artificial Light on the Emotional State of Adolescents in the Classroom

2020 ◽  
Vol 12 (10) ◽  
pp. 4263 ◽  
Author(s):  
David Baeza Moyano ◽  
Mónica San Juan Fernández ◽  
Roberto Alonso González Lezcano
Keyword(s):  
Blue Light ◽  
Emotional State ◽  
Spectral Composition ◽  
Lighting Design ◽  
Artificial Light ◽  
Visual Effects ◽  
Light Emitting ◽  
Interior Lighting ◽  
Indoor Lighting ◽  
Research Show

In recent years, articles have been published on the non-visual effects of light, specifically the light emitted by the new luminaires with light emitting diodes (LEDs) and by the screens of televisions, computer equipment, and mobile phones. Professionals from the world of optometry have raised the possibility that the blue part of the visible light from sources that emit artificial light could have pernicious effects on the retina. The aim of this work is to analyze the articles published on this subject, and to use existing information to elucidate the spectral composition and irradiance of new LED luminaires for use in the home and in public spaces such as educational centers, as well as considering the consequences of the light emitted by laptops for teenagers. The results of this research show that the amount of blue light emitted by electronic equipment is lower than that emitted by modern luminaires and thousands of times less than solar irradiance. On the other hand, the latest research warns that these small amounts of light received at night can have pernicious non-visual effects on adolescents. The creation of new LED luminaires for interior lighting, including in educational centers, where the intensity of blue light can be increased without any specific legislation for its control, makes regulatory developments imperative due to the possible repercussions on adolescents with unknown and unpredictable consequences.

scholarly journals Restoring the night sky darkness at Observatorio del Teide: First application of the model Illumina version 2

2020 ◽  
Vol 497 (3) ◽  
pp. 2501-2516 ◽  
Author(s):  
Martin Aubé ◽  
Alexandre Simoneau ◽  
Casiana Muñoz-Tuñón ◽  
Javier Díaz-Castro ◽  
Miquel Serra-Ricart
Keyword(s):  
Radiative Transfer Model ◽  
Small Scale ◽  
Transfer Model ◽  
Light Emitting ◽  
The Past ◽  
V Band ◽  
Tenerife Island ◽  
Sky Brightness ◽  
Night Sky ◽  
Sky Radiance

ABSTRACT The propagation of artificial light into real environments is complex. To perform its numerical modelling with accuracy, one must consider hyperspectral properties of the lighting devices and their geographic positions, the hyperspectral properties of the ground reflectance, the size and distribution of small-scale obstacles, the blocking effect of topography, the lamps angular photometry and the atmospheric transfer function (aerosols and molecules). A detailed radiative transfer model can be used to evaluate how a particular change in the lighting infrastructure may affect the sky radiance. In this paper, we use the new version (v2) of the Illumina model to evaluate a night sky restoration plan for the Teide Observatory located on the island of Tenerife, Spain. In the past decades, the sky darkness was severely degraded by growing light pollution on the Tenerife Island. In this work, we use the contribution maps giving the effect of each pixel of the territory to the artificial sky radiance. We exploit the hyperspectral capabilities of Illumina v2 and show how the contribution maps can be integrated over regions or municipalities according to the Johnson–Cousins photometric bands spectral sensitivities. The sky brightness reductions per municipality after a complete shutdown and a conversion to light-emitting diodes are calculated in the Johnson–Cousins B, V, R bands. We found that the conversion of the lighting infrastructure of Tenerife with LED (1800 and 2700 K), according to the conversion strategy in force, would result in a zenith V-band sky brightness reduction of ≈0.3 mag arcsec−2.

Blue like Diamond Light Emitting Devices to be Massproduced

1989 ◽  
Vol 162 ◽  
Author(s):  
M. Kadono ◽  
S. Hayashi ◽  
N. Hirose ◽  
K. Itoh ◽  
T. Inushima ◽  
...  
Keyword(s):  
Thin Films ◽  
Electronic Device ◽  
Electronic Devices ◽  
Chemical Properties ◽  
Wide Band ◽  
Wide Band Gap ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Device Applications ◽  
Diamond Thin Films

Recently, there has been considerable interest in electronic device applications of diamond thin films. The chemical properties of diamond is stable. So diamond thin films become very useful if they are used for electronic devices. We consider diamond thin films as blue like emitting devices because diamond has a wide band gap(about 5.5eV). Some light emitting devices have been known [1]. First of all we have been trying to deposit diamond thin films on the large areas. If they deposit on the large areas, light emitting devices may be massproduced.

scholarly journals Estimation of Ultraviolet-A Irradiance from Measurements of 368-nm Spectral Irradiance

2005 ◽  
Vol 22 (12) ◽  
pp. 1853-1863 ◽  
Author(s):  
R. H. Grant ◽  
J. R. Slusser
Keyword(s):  
United States ◽  
Radiative Transfer ◽  
Plant Productivity ◽  
The United States ◽  
Spectral Irradiance ◽  
Radiative Transfer Model ◽  
Mean Bias Error ◽  
Transfer Model ◽  
Semiempirical Model ◽  
Ultraviolet A

Abstract The estimation of ultraviolet-A (UV-A) radiation across the earth’s surface is needed to model plant productivity and future impacts of ultraviolet-B radiation on plant productivity. We have developed two models to estimate the UV-A irradiance from measurements of the diffuse and global spectral irradiance at 368 nm. The models were developed from 30-min-interval measurements made throughout 2000 at three locations across the United States and evaluated from 30-min measurements made throughout 2000 at three additional locations and throughout 2001 and 2002 at seven locations. UV-A irradiance was best estimated from measured global 368-nm irradiance and empirical functions defining the UV-A and 368-nm irradiance values estimated from a theoretical pseudospherical two-stream discrete-ordinates radiative transfer model. The radiative transfer model provided baseline irradiance relationships between UV-A irradiance and 368-nm spectral irradiance. The semiempirical model estimated the UV-A irradiance at seven locations across the United States with a mean bias error of 0.5 W m−2 and a root-mean-square error of 2 W m−2, corresponding to approximately ±4% of a clear-sky irradiance of 50 W m−2 for a solar zenith angle of 30°. This model error was comparable to the combined effect of previously estimated UV-A and 368-nm irradiance measurement errors.

scholarly journals Spectral UV Measurements of Global Irradiance, Solar Radiance, and Actinic Flux in New Zealand: Intercomparison between Instruments and Model Calculations

2008 ◽  
Vol 25 (6) ◽  
pp. 945-958 ◽  
Author(s):  
Mario Blumthaler ◽  
Barbara Schallhart ◽  
Michael Schwarzmann ◽  
Richard McKenzie ◽  
Paul Johnston ◽  
...  
Keyword(s):  
New Zealand ◽  
Total Ozone ◽  
Spectral Irradiance ◽  
Atmospheric Composition ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Total Ozone Mapping Spectrometer ◽  
Model Calculations ◽  
Global Irradiance ◽  
Sky Radiance

Abstract Presented here are the results of a short but intense measurement campaign at Lauder, New Zealand, in which spectral irradiance from instruments operated by the National Institute of Water and Atmospheric Research (NIWA) and Austria/Innsbruck (ATI) were traced to different irradiance standards and compared. The observed spectral differences for global irradiance were relatively small (<5%) and were consistent with those expected from observed differences in the radiation standards used by each group. Actinic fluxes measured by both groups were also intercompared and found to agree at the 10% level. The ATI instrument had the additional capability of measuring solar direct beam irradiance and sky radiances. These provided the first series of sky radiance measurements at this pristine Network for the Detection of Atmospheric Composition Change (NDACC) site. The polarization of sky radiance results were compared with estimates from a radiative transfer model without any aerosols and was found to be up to 25% smaller. Total ozone values derived from Total Ozone Mapping Spectrometer (TOMS), Dobson measurements by NIWA, spectral direct sun measurements by ATI, and spectral global irradiance measurements by NIWA agreed generally within 2%–3%.

scholarly journals Comparison of UV-RSS spectral measurements and TUV model runs for clear skies for the May 2003 ARM aerosol intensive observation period

2008 ◽  
Vol 8 (6) ◽  
pp. 1813-1821 ◽  
Author(s):  
J. J. Michalsky ◽  
P. W. Kiedron
Keyword(s):  
Radiative Transfer ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Spectral Irradiance ◽  
Radiative Transfer Model ◽  
Visible Range ◽  
Transfer Model ◽  
Intensive Observation ◽  
Aerosol Properties ◽  
Observation Period

Abstract. The first successful deployment of the fully-operational ultraviolet rotating shadow-band spectroradiometer occurred during the May 2003 US Department of Energy's Atmospheric Radiation Measurement program's Aerosol Intensive Observation Period. The aerosol properties in the visible range were characterized using redundant measurements with several instruments to determine the column aerosol optical depth, the single scattering albedo, and the asymmetry parameter needed as input for radiative transfer calculations of the downwelling direct normal and diffuse horizontal solar irradiance in clear-sky conditions. The Tropospheric Ultraviolet and Visible (TUV) radiative transfer model developed by Madronich and his colleagues at the US National Center for Atmospheric Research was used for the calculations of the spectral irradiance between 300–360 nm. Since there are few ultraviolet measurements of aerosol properties, most of the input aerosol data for the radiative transfer model are based on the assumption that UV input parameters can be extrapolated from the visible portion of the spectrum. Disagreements among available extraterrestrial spectra, which are discussed briefly, suggested that instead of comparing irradiances, measured and modeled spectral transmittances between 300–360 nm should be compared for the seven cases studied. Transmittance was calculated by taking the ratios of the measured irradiances to the Langley-derived, top-of-the-atmosphere irradiances. The cases studied included low to moderate aerosol loads and low to high solar-zenith angles. A procedure for retrieving single scattering albedo in the ultraviolet based on the comparisons of direct and diffuse transmittance is outlined.

scholarly journals Aerosol Single Scattering Albedo retrieval in the UV range: an application to OMI satellite validation

2009 ◽  
Vol 9 (5) ◽  
pp. 19009-19033 ◽  
Author(s):  
I. Ialongo ◽  
V. Buchard ◽  
C. Brogniez ◽  
G. R. Casale ◽  
A. M. Siani
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Spectral Irradiance ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Ozone Monitoring Instrument ◽  
Mean Values ◽  
Absorbing Aerosols

Abstract. The aerosol Single Scattering Albedo (SSA) and Absorbing Aerosol Optical Depth (AAOD) at 320.1 nm are derived at Rome site by the comparison between Brewer and modelled spectra. The UVSPEC radiative transfer model is used to calculate the UV irradiances for different SSA values, taking into account as input data total ozone and Aerosol Optical Depth (AOD) obtained from Brewer spectral measurements. The accuracy in determining SSA depends on the aerosol amount and on Solar Zenith Angle (SZA) value: SSA uncertainty increases when AOD and SZA decrease. The monthly mean values of SSA and AAOD during the period January 2005–June 2008 are analysed, showing a monthly and seasonal variability. It is found that the SSA and AAOD averages are 0.80±0.08 and 0.056±0.028, respectively. AAOD retrievals are also used to quantify the error in the Ozone Monitoring Instrument (OMI) surface UV products due to absorbing aerosols, not included in the current OMI UV algorithm. OMI and Brewer UV irradiances at 324.1 nm and Erythemal Dose Rates (EDRs) under clear sky conditions, are compared as a function of AAOD. Three methods are considered to investigate on the applicability of an absorbing aerosol correction on OMI UV data at Rome site. Depending on the correction methodology, the bias value decreases from 18% to 2% for spectral irradiance at 324.1 nm and from 25% to 8% for EDR.

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