Conceptualization of color temperature scenario applied to quality lighting design.

2019 ◽  
Vol 2019 (1) ◽  
pp. 99-103
Author(s):  
Estelle Guerry ◽  
Georges Zissis ◽  
Céline Caumon ◽  
Laurent Canale ◽  
Elodie Bécheras

Quality lighting is characterized by four major factors, one of them being the color temperature. When designed for elderly, this quality lighting can allow them to evolve within their environment safely, independently and above all comfort without having to focus on the effects of aging. This article aims to show the benefits of designing color temperature scenarios, made possible for example by dynamic LED lighting, thus contributing to the production of comfortable lighting and thus quality.

2019 ◽  
Vol 290 ◽  
pp. 183-189
Author(s):  
Mahmood Al Shafouri ◽  
Naser Mahmoud Ahmed ◽  
Zainuriah Hassan ◽  
Munirah Abdullah Almessiere

In thus study, Turmeric phosphor dye was extracted from Curcuma Longa L. via a simple technique using silica gel. The phosphor was used for light down-conversion of UV light for the manufacture white light emitting diode (WLED). The UV-LED was analyzed over 395nm wavelengths. The characteristics of the white light chromaticity were controlled by tuning the current and phosphor concentration. An optimum color rendering index (CRI) value of 63.4 was obtained. The chromaticity coordinates (CIE) and correlated color temperature (CCT) were measured for various currents and phosphor concentrations. The white phosphor exhibited CIE value of 0.355,0.338 and CCT of 4567 K. The concentration of phosphor and amount of applied current were confirmed to be major factors that control the intensity of white light emitted from the sample, where CIE and CRI of the emitted light steadily increased with the concentration of phosphor and current. Thus, phosphor concentration has a critical effect on conversion efficiency. Key words: Turmeric, phosphor, WLED, curcumin


2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Chung Won Lee ◽  
Jin Ho Kim

This study was conducted to verify how the illuminance and correlated color temperature of LED lighting affect working memory. For this study, an automatic LED lighting device based on a light sensor was developed and used, and the lighting conditions were treated with a total of six conditions (2 × 3): two illuminance conditions (dim: 400 lx, bright: 1,000 lx) and three correlated color temperature conditions (3,000 K, 5,000 K, and 7,000 K). There were 30 participants in the study, and the average age was 21.6 years (Standard deviation = 1.92). Participants were assigned to all six lighting conditions, and the placement order was randomized. For the measurement of working memory, 3-back task was used and the correct responses for 5 minutes were used as a dependent variable. As a result of repeated measures analysis of variance (ANOVA), both illuminance and correlated color temperature were found to be significant variables affecting working memory, and no interaction effect between illuminance and correlated color temperature was found. As a result of the post hoc verification conducted thereafter, the working memory performance in the bright light condition (1,000 lx) was 48.32 (Standard deviation = 15.63) on average, compared to 44.80 (Standard deviation = 15.29) in the relatively dim condition (400 lx). It was found that the condition of bright light was superior in performing working memory compared to relatively dim condition. The working memory performance in the correlated color temperature condition (5,000 K) was 48.32 (Standard deviation = 16.41) on average and higher than that of other color temperature conditions. As a result, working memory performance was the best in 1,000 lx, 5,000 K condition Mean = 53.43 (Standard deviation = 18.38), and 400 lx, 7,000 K condition Mean = 42.73 (Standard deviation = 17.68) showed the worst performance of working memory.


2018 ◽  
Author(s):  
Pedro Laguardia Tavares ◽  
José Machado Schroder Dutra ◽  
Dênis de Castro Pereira ◽  
Aline Rocha Silva ◽  
Vinicius Moraes de Albuquerque ◽  
...  

Author(s):  
NA Skoblina ◽  
OYu Milushkina ◽  
AM Kurgansky ◽  
SV Markelova ◽  
AP Tsameryan ◽  
...  

Object: The wide spread of gadgets among modern schoolchildren and their intensive use during breaks in school corridors and recreation areas indicates the necessity of improving illumination in school recreation areas to secure conditions suitable for intensive visual work. Thanks to their technical characteristics, durability and affordable price, LED light sources can ensure the implementation of this task. The objective of the study was to assess the impact of LED lighting of school corridors, halls and recreational facilities on visual acuity and psycho-emotional state of first graders in the course of a schoolyear. Materials and methods: In the corridors and recreation areas of the Dolgoprudninskaya Gymnasium (Moscow Region), fluorescent lamps were replaced by PrLUX-AU-36 LED lamps with Epistar LEDs, opal diffuser, 3600Lm luminous flux, and the color temperature of 4000K. Measurements of artificial lighting were taken before and after installing LED lamps using a TKA PKM 43 light meter. We conducted a study of visual acuity among 67 first graders (aged 7-8) in the annual dynamics from September to May using the Sivtsev-Golovin table placed in the Rota apparatus. Testing was conducted by a highly qualified ophthalmologist. The psycho-emotional state was assessed using the Luscher color test. Results: We observed a significant increase in visual acuity in children over the specified period indicating the absence of negative effects of LED lighting on the organ of vision. The results of the Lusher test proved the absence of negative dynamics, thus demonstrating null adverse health effects of LED lighting in the primary schoolchildren. The studies confirmed that the influence of that light load on vision and its negative non-visual effects were only potential.


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