Research on Visual Performance under Different Lighting Environments of LED Light Sources

2015 ◽  
Vol 731 ◽  
pp. 92-96
Author(s):  
Yu Liu ◽  
Hong Tao Miao ◽  
Min Huang ◽  
Ai Ping Liu ◽  
Xian Yao Wu
Keyword(s):  
Light Source ◽  
Visual Task ◽  
Visual Performance ◽  
Color Temperature ◽  
Light Sources ◽  
Physiological Changes ◽  
Led Light ◽  
Low Illumination ◽  
Different Color ◽  
The Relationship

In order to study the LED light source illumination and the correlated color temperature effect on the human eye visual performance and physiological changes, through the comparative experiments of visual task performances under the different color temperature (3000K low color temperature, 4000K intermediate color temperature) and the different illumination (1145lux high intensity, 500lux middle intensity, 288lux low illumination), study the relationship between the biological effect and visual performance from two aspects of the visual perception performance and the physical efficiency such as blood pressure and pulse. Research indicates that color temperature 3000K or 4000K, intensity of illumination in about 500lux LED light source is suitable to visual task.

Influence of the Parameters of Light Source on Observers’ Visual Performance

2015 ◽  
Vol 731 ◽  
pp. 124-128
Author(s):  
Min Huang ◽  
Zhen Zheng ◽  
Huan Jiang ◽  
Hao Xue Liu
Keyword(s):  
Light Source ◽  
Reading Rate ◽  
Mental Capacity ◽  
Visual Performance ◽  
Color Temperature ◽  
Light Sources ◽  
Accuracy Index ◽  
The Given ◽  
Dose Experiment

In order to investigate the influence of the light source with different illuminance and color temperature on the observers’ visual performance, five kinds of light sources were selected, named LED1, LED2, LED3, LED4 and Fluorescent, which have different illuminance or color temperature. 3 series of visual experiments, such as the ‘find out’ experiment, compared experiment, dose experiment were designed.13 observers were organized to carry out the experiment in the given time in turn. The reading rate, accuracy , index of mental capacity (IMC) and visual comfortable level score were analyzed, the results indicated that the light source with the lower color temperature and medium illuminance has the best visual performance and comfortable visual feel.

scholarly journals Lifespan Characteristics of SMD-Type LED Exit Lights

2021 ◽  
Vol 21 (2) ◽  
pp. 59-64
Author(s):  
Jongjin Jung
Keyword(s):  
Light Source ◽  
Heat Dissipation ◽  
Light Sources ◽  
Improve Product Quality ◽  
Electrical Characteristics ◽  
Led Light ◽  
Source Current ◽  
The Relationship ◽  
Top View ◽  
Future Management

In this study, the electrical characteristics of SMD-type LED light sources, which have been used for most exit lights since 2007, were analyzed. The relationship between the electrical characteristics of the LED light source and the life of the light source was analyzed. An LED exit light that used a top-view LED and a power LED was used for this experiment. The sizes of the exit lights were medium and small. In addition, the electrical characteristics of the LED light source were analyzed by measuring the input current, light source current, and power values related to the life of the LED. As a result, when the exit lights were of the same size, the top-view LED exit light required less power and lower current than the power LED exit light, and the current and power waveforms were also good. It was also confirmed that the power LED exit light was out of the range of rated power for some samples. Therefore, when developing an LED exit light, checking the voltage, current, power, and heat dissipation of the light source together will improve product quality and future management.

scholarly journals Daylight Spectrum Index: A New Metric to Assess the Affinity of Light Sources with Daylighting

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2545 ◽  
Author(s):  
Ignacio Acosta ◽  
Jesús León ◽  
Pedro Bustamante
Keyword(s):  
Light Source ◽  
Spectral Power ◽  
Color Space ◽  
Human Vision ◽  
Color Temperature ◽  
Light Sources ◽  
Current Scenario ◽  
Electric Light ◽  
Different Color ◽  
Color Rendering

The current scenario of colorimetry shows a wide variety of different metrics which do not converge in the assessment of the color rendering of light sources. The limitations of the Color Rendering Index have promoted the emergence of new metrics, such as the Color Quality Scale. As in the case of the previous metric, these new concepts are based on the analysis of the deviation of different color samples in a color space, contrasting the results with those obtained with a light source reference, which can vary depending on the color temperature. Within this context, the Daylight Spectrum Index is proposed. This new concept aims to determine the affinity with daylighting of electric light sources, comparing the resulting spectral power distributions of the lamps studied and that observed under natural light. The affinity of an electric light source with daylighting allows for lower energy consumption due to the better performance of human vision. The new metric proposed is evaluated following the results obtained from 80 surveys, demonstrating the usefulness of this new concept in the quantification of color rendering of LED lamps and the affinity of electric light sources with daylighting.

scholarly journals Analysis on High-Power Seaport LED Luminaire with Uniform Light Distribution Based on Optimized Lens and Heatsink

2021 ◽  
Vol 11 (9) ◽  
pp. 4035
Author(s):  
Jinsheon Kim ◽  
Jeungmo Kang ◽  
Woojin Jang
Keyword(s):  
Light Source ◽  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Light Distribution ◽  
Light Sources ◽  
Led Light ◽  
High Power Led ◽  
Distribution Requirement ◽  
Lighting Application

In the case of light-emitting diode (LED) seaport luminaires, they should be designed in consideration of glare, average illuminance, and overall uniformity. Although it is possible to implement light distribution through auxiliary devices such as reflectors, it means increasing the weight and size of the luminaire, which reduces the feasibility. Considering the special environment of seaport luminaires, which are installed at a height of 30 m or more, it is necessary to reduce the weight of the device, facilitate replacement, and secure a light source with a long life. In this paper, an optimized lens design was investigated to provide uniform light distribution to meet the requirement in the seaport lighting application. Four types of lens were designed and fabricated to verify the uniform light distribution requirement for the seaport lighting application. Using numerical analysis, we optimized the lens that provides the required minimum overall uniformity for the seaport lighting application. A theoretical analysis for the heatsink structure and shape were conducted to reduce the heat from the high-power LED light sources up to 250 W. As a result of these analyses on the heat dissipation characteristics of the high-power LED light source used in the LED seaport luminaire, the heatsink with hexagonal-shape fins shows the best heat dissipation effect. Finally, a prototype LED seaport luminaire with an optimized lens and heat sink was fabricated and tested in a real seaport environment. The light distribution characteristics of this prototype LED seaport luminaire were compared with a commercial high-pressure sodium luminaire and metal halide luminaire.

scholarly journals An Efficient Method for LED Light Sources Characterization

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1089 ◽  
Author(s):  
Sara Raggiunto ◽  
Alberto Belli ◽  
Lorenzo Palma ◽  
Piergiovanni Ceregioli ◽  
Massimo Gattari ◽  
...  
Keyword(s):  
Efficient Method ◽  
Least Squares Method ◽  
Color Temperature ◽  
Experimental Setup ◽  
Light Sources ◽  
Careful Study ◽  
Source Characterization ◽  
Led Light ◽  
Lighting Systems ◽  
Led Drivers

Digital LED drivers capable of blending the spectrum of two LED fixtures with different Correlated Color Temperatures through the LEDs’ power supply control are widespread. However, the digital control of lighting systems is possible only after a careful study of the LED’s response, in terms of illuminance and Correlated Color Temperature. The proposed work takes advantage of the Tunable White technology for the realization of an efficient method for LED light source characterization. In order to evaluate how the light changes as a function of the electric power supplied by the LED drivers, an experimental setup to characterize LED light sources has been designed. Starting from the data acquired from the experimental setup, a model for dimming the LED driver and obtaining the desired values of quality of light has been developed. The proposed model is based on the least squares method and its accuracy is evaluated by comparing the obtained values of illuminance and Correlated Color Temperature with those measured by an illuminance spectrophotometer. Results achieved an error of 0.3% for Correlated Color Temperature and 1.5% for illuminance using the proposed approximation functions.

scholarly journals Photobiocatalytic alcohol oxidation using LED light sources

2017 ◽  
Vol 19 (2) ◽  
pp. 376-379 ◽  
Author(s):  
M. Rauch ◽  
S. Schmidt ◽  
I. W. C. E. Arends ◽  
K. Oppelt ◽  
S. Kara ◽  
...  
Keyword(s):  
Light Source ◽  
Photocatalytic Oxidation ◽  
Alcohol Oxidation ◽  
Light Sources ◽  
Blue Led ◽  
Led Light

The photocatalytic oxidation of NADH using a flavin photocatalyst and a simple blue LED light source is reported.

Optimization Algorithm of Correlated Color Temperature for LED Light Sources by Dichotomy

2009 ◽  
Vol 29 (10) ◽  
pp. 2791-2794 ◽  
Author(s):  
林岳 Lin Yue ◽  
叶烈武 Ye Liewu ◽  
刘文杰 Liu Wenjie ◽  
吕毅军 Lü Yijun
Keyword(s):  
Optimization Algorithm ◽  
Color Temperature ◽  
Light Sources ◽  
Led Light

scholarly journals Impact of different standard lighting sources on red jadeite and color quality grading

2019 ◽  
Vol 23 (4) ◽  
pp. 371-378
Author(s):  
Xin Pan ◽  
Ying Guo ◽  
Ziyuan Liu ◽  
Zikai Zhang ◽  
Yuxiang Shi
Keyword(s):  
Light Source ◽  
Color Space ◽  
Sample Surface ◽  
Color Temperature ◽  
Integrating Sphere ◽  
Light Sources ◽  
Light Spectrum ◽  
Fisher Discriminant Analysis ◽  
Fisher Discriminant ◽  
Quality Grading

The purpose of this paper is to investigate the standard light source for grading and displaying the color of red jadeite and to classify the color. With Raman spectrometer, ultraviolet-visible spectrophotometer and X-ray fluorescence spectrometer, the results show that, the Fe 3+ is the main chromogenic mineral of red jadeite, which negatively correlates with the tonal angle, while the color of red jadeite has a positive correlation with the hematite content. The color of 120 red jadeite samples was examined by collecting the reflective signaled from the sample surface using an integrating sphere with the portable X-Rite SP62 spectrophotometer based on CIE 1976 L*a*b* uniform color space. The color parameters of jadeite samples under D65, A and CWF standard light sources were analyzed. The light spectrum of D65 light source is continuous, relatively smoothed with high color temperature, which makes the sample color close to that under the natural light and can be used as the best evaluation light source. A light source contributes to improve the red tone of jadeite, which is the best light source for commercial display of red jadeite. CWF light source can be used as the auxiliary lighting for color evaluation. The color of red jadeite is divided into five levels from best to worst using K-Means cluster analysis and Fisher discriminant analysis under D65 light source: Fancy Vivid, Fancy Deep, Fancy Intense, Fancy dark and Fancy.

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