Illuminance-spatial-distribution-based total luminous flux determination for white LEDs

2011 ◽  
Author(s):  
N. Vidal ◽  
E. Rosas ◽  
Juan B. Hurtado-Ramos
Keyword(s):  
Spatial Distribution ◽  
Luminous Flux ◽  
White Leds ◽  
Flux Determination

scholarly journals GROWING TECHNIQUES OF PERFORATE ST. JOHN’S WORT(HYPERICUM PERFORATUM L.)FOR PHOTOCULTURE

2021 ◽  
pp. 44-50
Author(s):  
P.N. Makarov ◽  
◽  
T.A. Makarova ◽  
Z.A. Samoylenko ◽  
N.M. Gulakova ◽  
...  
Keyword(s):  
Hypericum Perforatum ◽  
Natural Habitat ◽  
Leaf Size ◽  
Luminous Flux ◽  
Color Temperature ◽  
White Leds ◽  
St John’S Wort ◽  
St John's Wort ◽  
Shoot Number ◽  
Hypericum Perforatum L

This paper discusses the productivity evaluation results (shoot length, shoot number, leaf size, and yields) of hy-droponically grown perforate St. John’s wort (Hypericum perforatum L.). Hydroponic technique enables year-round growing of this medicinal plant preserving natural plant population in the Khanty-Mansiysk Autonomous District -Yugra; perforate St. John’s wortis listed in the District’s Red Book as the species that should be closely monitored in its natural habitat. A vertical ebb-and-flow hydroponic unit was used for growing. The research target was the Optimist variety of perforate St. John’s wort. Generally ac-cepted research methods were applied. Phytopathological evaluation of the perforate St. John’s wort plantation re-vealed low level of infestation with fusarium disease (less than 5%). The experiment showed that the plants reached the best values of all growth indices when grown under white lights of luminous flux of 8000 lm, color temperature of 4000 K, and РРF of 165 μmol s m2. Moreover, lighting with white LEDs stimulates transition of growing plants to flowering stage on the 97th day after planting and increas-es yield to 3.12 kg m2. The variety Optimist variety of perfo-rate St. John’s wort in hydroponic environment forms creeping, aggressively branching shoots that should be considered during growing.

scholarly journals Triple-layer remote phosphor structure: a novel option for the enhancement of WLEDs’ color quality and luminous flux

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
My Hanh Nguyen Thi ◽  
Phung Ton That ◽  
Nguyen Doan Quoc Anh ◽  
Tran Thanh Trang
Keyword(s):  
Performance Enhancement ◽  
Light Output ◽  
Luminous Flux ◽  
White Leds ◽  
Color Quality ◽  
Quality Scale ◽  
Color Uniformity ◽  
Remote Phosphor ◽  
Research Findings ◽  
Color Rendering

Abstract The remote phosphor as a lighting structure has outstanding luminous efficiency compared to other options, such as conformal or in-cup. However, the lack of uniformity in distributed color has prevented remote phosphor from wider development. The answer to the chromatic performance enhancement that has been suggested by numerous researchers is the multi-layer configuration with two or three different types of chromatic phosphor. The research purpose is to select the best configuration for multi-chip white LEDs (WLEDs) to achieve optimal results in color quality scale (CQS), color rendering index (CRI), light output and color homogeneity. WLEDs mentioned in this paper have two distinct color temperatures, 6600 K and 7700 K. Experimental results show that the remote phosphor structure with three phosphor layers is superior in terms of color rendering, chromatic performance, and emitted light. The deviation of correlated color measured in this structure is also low, which means that the color uniformity is greatly enhanced in this multi-layer lighting structure. This result can be demonstrated by analyzing the scattering characteristics of the phosphoric layers using the Mie theory. The research findings have proven the effectiveness of the multi-phosphor configuration and can serve as a guideline to fabricate WLEDs with better performance.

Analysis of junction temperature and modification of luminous flux degradation for white LEDs in a thermal accelerated reliability test

2016 ◽  
Vol 55 (22) ◽  
pp. 5909 ◽  
Author(s):  
Hong-Liang Ke ◽  
Lei Jing ◽  
Jian Hao ◽  
Qun Gao ◽  
Yao Wang ◽  
...  
Keyword(s):  
Luminous Flux ◽  
Junction Temperature ◽  
Reliability Test ◽  
White Leds

Effects of YAG: Ce Phosphor Particle Size on Luminous Flux and Angular Color Uniformity of Phosphor-Converted White LEDs

2012 ◽  
Vol 8 (6) ◽  
pp. 329-335 ◽  
Author(s):  
Zong-Yuan Liu ◽  
Cheng Li ◽  
Bin-Hai Yu ◽  
Yao-Hao Wang ◽  
Han-Ben Niu
Keyword(s):  
Particle Size ◽  
Luminous Flux ◽  
Phosphor Particle ◽  
White Leds ◽  
Color Uniformity

scholarly journals Exellent Color Quality and Luminous Flux of Wleds Using Triple-Layer Remote Phosphor Configuration

2020 ◽  
Vol 4 (1) ◽  
pp. 74
Author(s):  
Min-Feng Lai ◽  
Hsiao-Yi Lee ◽  
Doan Quoc Anh Nguyen
Keyword(s):  
Red Light ◽  
Green Light ◽  
Luminous Flux ◽  
Green Phosphor ◽  
Light Component ◽  
Research Results ◽  
White Leds ◽  
Color Quality ◽  
Triple Layer ◽  
Remote Phosphor

This study proposed a triple-layer remote phosphor (TRP) structure to improve the color and luminous flux of white LEDs (WLEDs). TRP structure consists of 3 different phosphor layers: yellow YAG:Ce3+ layer below, red CaMgSi2O6:Eu2+,Mn2+ phosphor on top and green layer Ba2Li2Si2O7:Sn2+,Mn2+  phosphor in the middle. Using red CaMgSi2O6:Eu2+,Mn2+ to control the red light component leads to increased color rendering index (CRI). Utilize the green CaMgSi2O6:Eu2+,Mn2+ phosphor to control the green light component results in the increase in luminous efficacy (LE) of WLEDs. Furthermore, when the concentration of these two phosphors increased, yellow layer concentration YAG:Ce3+ decreased to maintain average correlated color temperatures (ACCTs) in the range from 6000 K-8500K. Besides CRI and LE, color quality scale (CQS) is also analyzed through concentration control of green phosphor and red phosphor. The research results show that the higher the concentration of CaMgSi2O6:Eu2+,Mn2+, the better for CRI. In contrast, CRI decreased significantly when increasing the concentration of Ba2Li2Si2O7:Sn2+,Mn2+. Meanwhile, CQS achieve notable enhancement in the concentration range of 10% -14% CaMgSi2O6:Eu2+,Mn2+, regardless of Ba2Li2Si2O7:Sn2+,Mn2+ concentration. LE, in particular, can also increase by more than 40% along with the improvement of CRI and CQS with the reduction of the backscattered light and addition of green light. Research results are a valuable reference for producers who wish to improve the color quality and enhance the luminous flux of WLEDs. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

scholarly journals The effectiveness of MgCeAl11O19:Tb3+ phosphor in enhancing the luminous efficacy and color quality of multi-chip white LEDs

2020 ◽  
Vol 10 (5) ◽  
pp. 4631
Author(s):  
Nguyen Thi Phuong Loan ◽  
Nguyen Doan Quoc Anh
Keyword(s):  
Optical Properties ◽  
Mie Scattering ◽  
Luminous Flux ◽  
Color Temperature ◽  
White Leds ◽  
Color Quality ◽  
Supporting Material ◽  
Mie Scattering Theory ◽  
Led Lights

In this research paper, we introduced yellow-green MgCeAl11O19:Tb3+ asa new phosphor ingredient to adapt to the quality requirements onthe chromatic homogeneity and emitted luminous flux of modern multi-chip white LED lights (MCW-LEDs). The results from experiments and simulation show that employing MgCeAl11O19:Tb3+ phosphor can lead to much better optical properties and therefore is a perfect supporting material to achieve the goals of the research. When the MgCeAl11O19:Tb3+ phosphor is added into the phosphorus composite which already contains YAG: Ce3+ particles, and the silicone glue, it affects the optical properties significantly. In other words, the concentration of this phosphor can determine the efficiency of lumen output and chromatic homogeneity of WLEDs. In specific, as the concentration of MgCeAl11O19:Tb3+ go up, the luminous yield will increase accordingly, though there is an insignificant decrease in CQS. Moreover, if the MgCeAl11O19:Tb3+ concentration reduce a little bit, it is possible to better the correlated color temperature uniformity and lumen efficacy of LED packages. In addition, the Mie scattering theory, Monte Carlo simulation and LightTools 8.3.2 software are employed to analyze and simulate the LED packages’ structure as well as the phosphor compound.

The characteristic analysis of continuous light diodes

2021 ◽  
pp. 2150247
Author(s):  
I. T. Huseynov
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Light Flux ◽  
Continuous Light ◽  
Luminous Flux ◽  
Characteristic Analysis ◽  
Light Emitting ◽  
White Leds ◽  
Composite Solution ◽  
White Light Emitting Diodes

Photoluminescence (PL) spectra, light flux, color temperatures and color coordinates of white light emitting diodes that are based on CaGa2S4:Eu[Formula: see text]–CaS:Eu[Formula: see text] composite solution and industrial phosphor were analyzed. The study was carried out continuously for a 1000 h with two white LEDs which based on an exciting InGaN wavelength of 450 nm with a power of 10 W. Luminous flux and color temperatures were investigated during 200, 400, 600, 800 and 1000 h. All experiments were carried out for both CaGa2S4:Eu[Formula: see text]–CaS:Eu[Formula: see text] and industrial phosphor and comparatively analyzed. Consequently, the application perspectives of CaGa2S4:Eu[Formula: see text]–CaS:Eu[Formula: see text] composite solution in the white LEDs technologies are presented.

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