scholarly journals Assessment of blue light retinal hazard of lamps and lights used in automotive

2018 ◽  
Vol 19 (6) ◽  
pp. 548-551
Author(s):  
Marcin Legierski ◽  
Piotr Michałek
Keyword(s):  
Blue Light ◽  
Self Assembly ◽  
Luminous Intensity ◽  
Light Sources ◽  
Colour Temperature ◽  
Led Light ◽  
Chromaticity Coordinates ◽  
Daytime Running Lights

The article contains results of the research on the assessment of the blue light retinal hazard by lighting devices used in the automotive with LED light sources. The study was subject to daytime running lights and work lamps available on the market for self-assembly in vehicles. The study method was presented using a matrix luminance meter and spectroradiometer. The necessary photometric and radiometric tests were carried out. Assessment of blue light hazard according to the PN-EN 62471: 2010 was made. Obtained results were referred to maximum luminous intensity, chromaticity coordinates and correlated colour temperature of tested devices.

Performance Optimization of Blue-light Blocking Lens Through Analysis of Blue Light Emitted from LED Light Sources

2016 ◽  
Vol 21 (4) ◽  
pp. 393-400 ◽  
Author(s):  
Younghyun Son ◽  
Seok-Jun Yang ◽  
Chang Jin Kim ◽  
Gyeong Sun Lee ◽  
Su Mi Choi ◽  
...  
Keyword(s):  
Blue Light ◽  
Performance Optimization ◽  
Light Sources ◽  
Led Light

LED life prediction based on lumen depreciation and colour shift

2016 ◽  
Vol 49 (1) ◽  
pp. 84-99 ◽  
Author(s):  
AN Padmasali ◽  
SG Kini
Keyword(s):  
Life Prediction ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Light Output ◽  
Light Sources ◽  
Colour Stability ◽  
Light Emitting ◽  
Colour Temperature ◽  
Life Estimation ◽  
Chromaticity Coordinates

Light emitting diodes, with advantages in energy savings, luminous efficacy and greater reliability, are becoming preferred over conventional white light sources. Currently, only light output depreciation is considered for life estimation of light emitting diode luminaires but it is recommended to include colour shift variations for applications demanding colour stability. In this paper, an extended Kalman filter is employed to determine L70 life and colour temperature degradation over life of a light emitting diode luminaire. The colour shift in terms of Duv is determined by statistical polynomial cure fitting. The variation in chromaticity coordinates over life is determined and life based on colour shift is determined by acceptable Duv limits. The results are compared to life determined by the IES-TM-21 method and the correlated colour temperature limits taken from the luminaire data sheet.

scholarly journals METAMERISM INDEX OF LED LIGHT ON HALFTONE COLOUR IMAGES

2021 ◽  
Vol 30 (2) ◽  
pp. 1-9
Author(s):  
Igor Zjakić ◽  
◽  
Ivana Ljevak ◽  
Albulena Bilalli ◽  
◽  
...  
Keyword(s):  
Visual Perception ◽  
Skin Color ◽  
Large Change ◽  
Limited Range ◽  
Light Sources ◽  
Light Conditions ◽  
Colour Temperature ◽  
Led Light ◽  
Lighting Conditions ◽  
Small Index

Skin face detection in photo imaging, is an important component of systems for detecting similarities in visual perception, tracing faces through illumination and metamerism. This paper presents an evaluation of the skin perception under standardized conditions of varied light sources: cool-white fluorescent “store light”, 6500K fluorescent “daylight”, and incandescent “home light”, Led light 6500 K, 2700K, 4000K CCT. In cases where the discrepancy is large, the resulting index of metamerism can be misleading. A small index of metamerism and a large change of color under illuminant metamerism has a different interpretation than what is perceived. This has been demonstrated through small colour variations in print through CMYK colors. The implication is that particular indices of metameric should only account for a limited range under different light conditions. The method used in this paper is based on visual perception, which aim to work with a wide variety of individuals, under varying lighting conditions under the influence of standard daylight, but in this case we also used the Led light 6500K correlated colour temperature, and variations of skin color tones, comparing the illuminant metamerism of visual perception based on different reflectance power distributions (SPDs).

Spectral Design and Optimization of White LED Light Sources with Low Blue Light Hazard

2019 ◽  
Vol 56 (18) ◽  
pp. 182302
Author(s):  
周孟欣 Mengxin Zhou ◽  
朱大庆 Daqing Zhu ◽  
廖欣怡 Xinyi Liao
Keyword(s):  
Blue Light ◽  
Light Sources ◽  
White Led ◽  
Led Light ◽  
Design And Optimization ◽  
Spectral Design

scholarly journals Effect of led light on in vitro growth and developmentof Anoectochilus roxburghii

2018 ◽  
Vol 15 (1) ◽  
pp. 97-104
Author(s):  
Đỗ Thị Gấm ◽  
Chu Hoàng Hà Chu Hoàng Hà Chu Hoàng Hà ◽  
Phạm Bích Ngọc Phạm Bích Ngọc Phạm Bích Ngọc ◽  
Nguyễn Khắc Hưng ◽  
Phan Hồng Khôi ◽  
...  
Keyword(s):  
Growth And Development ◽  
Red Light ◽  
Light Condition ◽  
Luminous Intensity ◽  
Fluorescent Light ◽  
Light Sources ◽  
Plant Weight ◽  
Led Light ◽  
Anoectochilus Roxburghii

Recently, LED lighting technology has been developed fast and strongly. It has been widely used in many new fields. LEDs have been tested as an artificial light source during micropagation and tissue culture of various plants species as an alternative to traditional light sources to save energy and improve the efficiency of the culture process. In this study, effects of LED light at different wavelengths and luminous intensities on growth of Anoectochilus roxburghii's buds in vitro were investigated. Anoectochilus's buds were cultured under the different light conditions, such as LED in monochromatic red (R), LED in monochromatic green (B) , LED in the green and red light combining with warm white light (W) in different ratios (BRW 1, BRW2, BRW3 and BR). After 3 months of culture, the results showed LED B at strong luminous intensity (79 ± 3 μmol.m-2.s-1) inhibited the growth and development of Anoectochilus roxburghii. In contrast, BR LED with low luminous intensity (30 ± 1μmol.m-2.s-1) had made a positive effect on growth and development of Anoectochilus roxburghii. The plant height (5,88 cm), root length (1,33 cm), fresh plant weight (0,169 g/plant), leaf area (0,82 cm2), fresh leaf weight (18,33 mg/leaves) of plants in vitro were found higher than those of plants grown under T5 fluorescent lighting conditions (as control). Besides, chlorophyll a, chlorophyll b and total chlorophyll content of leaves (285,40 µg/g, 196,40 µg/g, 481,80 µg/g respectively) were higher than in the control and other versions of LED combine. The results also showed that the LED light with combined ratio of BR = 1: 4 at luminous intensity of 30 μmol.m-2.s-1 were suitable for the growth of Anoectochilus roxburghii. Therefore, BR LED (1:4) light condition should be replaced fluorescent light sources in vitro culture of Anoectochilus roxburghii in future.

Highly efficient and dual broad emitting light convertor: an option for next-generation plant growth LEDs

2019 ◽  
Vol 7 (12) ◽  
pp. 3617-3622 ◽  
Author(s):  
Mingcai Li ◽  
Xuejie Zhang ◽  
Haoran Zhang ◽  
Weibin Chen ◽  
Li Ma ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Plant Growth ◽  
Blue Light ◽  
Red Light ◽  
Light Sources ◽  
Full Width ◽  
Half Maximum ◽  
Next Generation ◽  
Led Light ◽  
Generation Plant

At present, blue-red composite LED light sources used for plant lighting are mainly composed of blue light and red light; the blue light is provided by gallium nitride LED chips, but the full-width at half-maximum (FWHW) is only approximately 25 nm, while the blue light required by plants for photosynthesis is wider.

The Influence Of The Led Luminaires Electrical Parameters On Their Correlated Colour Temperature During Operation Mode

2020 ◽  
pp. 89-96
Author(s):  
Sergei S. Kapitonov ◽  
Alexei S. Vinokurov ◽  
Sergei V. Prytkov ◽  
Sergei Yu. Grigorovich ◽  
Anastasia V. Kapitonova ◽  
...  
Keyword(s):  
Operation Mode ◽  
Light Sources ◽  
Electrical Parameters ◽  
Colour Temperature ◽  
Radiation Spectra ◽  
Service Period ◽  
Close Proximity ◽  
Definition Of ◽  
Comprehensive Study

The article describes the results of comprehensive study aiming at increase of quality of LED luminaires and definition of the nature of changes in their correlated colour temperature (CCT) in the course of operation. Dependences of CCT of LED luminaires with remote and close location of phosphor for 10 thousand hours of operation in different electric modes were obtained; the results of comparison between the initial and final radiation spectra of the luminaires are presented; using mathematical statistics methods, variation of luminaire CCT over the service period claimed by the manufacturer is forecast; the least favourable electric operation modes with the highest CCT variation observed are defined. The obtained results have confirmed availability of the problem of variation of CCT of LED luminaires during their operation. Possible way of its resolution is application of more qualitative and therefore expensive LEDs with close proximity of phosphor or LEDs with remote phosphor. The article may be interesting both for manufacturers and consumers of LED light sources and lighting devices using them.

Design of Solar-Powered LED Road Lighting System

2019 ◽  
pp. 75-85
Author(s):  
Canan Perdahci ◽  
Hamdi Ozkan
Keyword(s):  
High Pressure ◽  
Renewable Energy Sources ◽  
Junction Temperature ◽  
Mercury Vapour ◽  
Light Sources ◽  
Street Lighting ◽  
Led Light ◽  
Road Lighting ◽  
Lighting Systems ◽  
High Pressure Sodium Lamp

Turkey is rich in terms of renewable energy sources and, therefore, is now encouraging the use of sustainable clean lighting systems in road applications. High pressure sodium lamp is the most widely used type in main roads, but other types of lamps such as mercury vapour lamps or metal halide lamps can be utilized for street lighting. Since it enables energy and money saving, LED light technology has replaced high pressure sodium lamps nowadays. Once solar power system (PV) is integrated with LED lamp for street lighting, the amount of saving and local impact might be enriched. LEDs used as light sources in road lighting luminaires with rising lumen values, decreasing junction temperature, higher colour rendering efficiency, longer lifetime have become more efficient than many light sources with the latest developments. Since the structure of the luminaires in which the LED light sources are used differs from that of the conventional light sources, the optical, thermal and electrical design of the LED luminaires must be considered differently. Thus, this study concentrates upon design considerations and the operating principle of solarpowered LED road lighting luminaire in details. Also, a simple solar panel system was designed and the economical values obtained at the end of 20 years were compared when using the ongrid system and the off-grid system.

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