scholarly journals Enhancing Luminous Efficacy of White Led Lamp Using Ca2MgSi2O7:Eu2+ Phosphor

2018 ◽  
Vol 2 (2) ◽  
pp. 103
Author(s):  
Doan Quoc Anh Nguyen ◽  
Thi Phuong Thao Nguyen ◽  
Postava Kamil
Keyword(s):  
Rapid Development ◽  
Essential Element ◽  
Luminous Flux ◽  
Luminous Efficacy ◽  
Light Emitting ◽  
White Leds ◽  
Creative Commons ◽  
Quality Scale ◽  
White Light Emitting Diodes

Along with the rapid development of science and technology in today's society, lighting technology, especially white light-emitting diodes (WLEDs), has become a critical and essential element in almost every field of our daily life. Therefore, the enhancement of luminous efficiency has become an important objective in the production of white LEDs to serve the needs of customers. This paper presents the influence of Ca2MgSi2O7:Eu2+ green luminescent phosphor on the light quality of WLEDs. In this work, the green-emitting Ca2MgSi2O7:Eu2+ phosphor is added into the in-cup phosphor configuration, which leads to the varying of the scattering property of this compounding. This is proved through the scattering coefficient from Mie-theory. Besides, the color quality scale which is called CQS index of WLEDs is also verified. The achieved results indicate that the luminous efficacy increases significantly if the Ca2MgSi2O7:Eu2+ concentration is varied. The smaller the Ca2MgSi2O7:Eu2+ size is used, the higher the luminous flux is obtained. However, the CQS can decrease if Ca2MgSi2O7:Eu2+ concentration is adjusted in another direction. Therefore, it is vital to select a suitable concentration and size of Ca2MgSi2O7:Eu2+ for enhancing the luminous efficacy of WLEDs, and the benet of this phosphor in creating white WLED packages is a potential solution for developing LED illumination technology.  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 effect green YF3:ER3+,YB3+ phosphor on luminous flux and color quality of multi-chip white light-emitting diodes

2021 ◽  
Vol 11 (6) ◽  
pp. 4810
Author(s):  
My Hanh Nguyen Thi ◽  
Nguyen Thi Phuong Loan ◽  
Thuc Minh Bui ◽  
Anh Tuan Le
Keyword(s):  
White Light ◽  
Light Output ◽  
Luminous Flux ◽  
Green Phosphor ◽  
Light Emitting ◽  
Color Quality ◽  
Quality Scale ◽  
White Light Emitting Diodes ◽  
New Generation

The purpose of this paper is to demonstrate the advantages of the green phosphor YF<sub>3</sub>:Er<sup>3+</sup>,Yb<sup>3+ </sup>combined with multi-chip package to the enhancement of lighting efficiency of modern WLEDs. In an effort to improve the quality of WLEDs and create a new generation of lighting device, green phosphor YF<sub>3</sub>:Er<sup>3+</sup>,Yb<sup>3+ </sup>is added into the phosphor compounding of the WLED package to improve the color quality and lighting capacity. Through experiments, WLEDs with YF<sub>3</sub>:Er<sup>3+</sup>,Yb<sup>3+ </sup>green phosphor has shown improved results in lighting performance specifically in color homogeneity and light output of WLEDs in the ACCT range from 5600-7000 K. However, the color quality scale (CQS) declines gradually. Therefore, if the appropriate concentration and size of YF<sub>3</sub>:Er<sup>3+</sup>,Yb<sup>3+</sup> are determined, the performance of MCW-LEDs will be enhanced and become more stable.

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.

scholarly journals Excellent Luminous Efficacy and Color Homogeneity of White Light-Emitting Diodes with YPO4:Ce3+:Tb3+ Phosphor

2018 ◽  
Vol 72 ◽  
pp. 02002
Author(s):  
Vo Phu Thoai ◽  
Nguyen Doan Quoc Anh
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
White Led ◽  
Gradual Decline ◽  
Luminous Efficacy ◽  
Light Emitting ◽  
Color Quality ◽  
Quality Scale ◽  
Color Uniformity ◽  
White Light Emitting Diodes

In this paper, we focus on researching the method, which the color homogeneity and the lumen output of multi-chip white LED lamps (MCW-LEDs) need to support for increasing the efficiency. The successful results can be achieved by mixing the green YPO4:Ce3+:Tb3+ phosphor with their phosphor compounding. Through experiment results, we assert that the MCW-LEDs can achieve the significant consequence in performance by following that method and it is also again confirmed that when the concentration of YPO4:Ce3+:Tb3+ has tendency to increase, which impulse the development of the color uniformity and the luminous efficacy of MCW-LEDs with average correlated color temperatures (CCT) of 8500 K, while the color quality scale shows signs of gradual decline. It is not difficult to gain incredible presentation of MCW-LEDs if we are clever in choosing the suitable concentration and size of YPO4:Ce3+:Tb3+.

scholarly journals The Impacts of Red-Emitting SrwFxByOz:Eu2+,Sm2+ Phosphor on Color Quality of Dual-Layer Phosphor Geometry

2018 ◽  
Vol 2 (3) ◽  
pp. 208
Author(s):  
Doan Quoc Anh Nguyen
Keyword(s):  
Luminous Flux ◽  
Creative Commons ◽  
Color Quality ◽  
Yellow Phosphorus ◽  
Quality Scale ◽  
Remote Phosphor ◽  
Different Color ◽  
Color Rendering ◽  
Open Access Article

When the features of remote phosphor structure are compared with these of conformal phosphor or in-cup phosphor, it is recognized that it is more outstanding than the rest about luminous flux but the quality of color tends to be worse. Through that we have grasped these disadvantages and find out many studies in order to improve the color of the remote phosphor structure. In this study, we propose a dual-layer remote phosphor structure that could improve the color rendering index (CRI) and color quality scale (CQS) for WLEDs. In this study, three similar WLEDs structures but having different color temperatures including 5600 K, 6600 K and 7700K are applied. The principal idea is putting a red phosphoric layer SrwFxByOz:Eu2+,Sm2+ on the yellow phosphorus layer YAG:Ce3+. The results show that SrwFxByOz:Eu2+,Sm2+  brings great benefits to increasing CRI and CQS. Specifically, the greater the concentration of SrwFxByOz:Eu2+,Sm2+ has, the higher CRI and CQS get. However, the declining trend of luminous flux occurs when the SrwFxByOz:Eu2+,Sm2+ concentration exceeds the level. This can be demonstrated through the results of the study and be explained by the Mie dispersion theory and the Lambert-Beer law. The results of this article are important in making WLEDs of higher color quality.  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 Novel lighting properties of white LEDs with two-layered remote phosphor package using red-emitting α-SrO·3B2O3:Sm2+ phosphor

2017 ◽  
Vol 35 (3) ◽  
pp. 618-625
Author(s):  
Tran Hoang Quang Minh ◽  
Nguyen Huu Khanh Nhan ◽  
Nguyen Doan Quoc Anh ◽  
Hsiao-Yi Lee
Keyword(s):  
Lower Layer ◽  
Luminous Flux ◽  
Color Temperature ◽  
Phosphor Layer ◽  
Light Emitting ◽  
White Leds ◽  
Color Uniformity ◽  
Remote Phosphor ◽  
White Light Emitting Diodes ◽  
Color Rendering

AbstractThis paper investigates a method for improving the lighting performance of white light-emitting diodes (WLEDs), packaged using two separating remote phosphor layers, yellow-emitting YAG:Ce phosphor layer and red-emitting α-SrO·3B2O3:Sm2+ phosphor layer. The thicknesses of these two layers are 800 μm and 200 μm, respectively. Both of them have been examined at average correlated color temperatures (CCT) of 7700 K and 8500 K. For this two-layer model, the concentration of red phosphor has been varied from 2 % to 30 % in the upper layer, while in the lower layer the yellow phosphor concentration was kept at 15 %. It was found interesting that the lighting properties, such as color rendering index (CRI) and luminous flux, are enhanced significantly, while the color uniformity is maintained at a level relatively close to the level in one-layer configuration (measured at the same correlated color temperature). Besides, the transmitted and reflected light of each phosphor layer have been revised by combining Kubelka-Munk and Mie-Lorenz theories. Through the analysis, it is demonstrated that the packaging configuration of two-layered remote phosphor that contains red-emitting α-SrO·3B2O3:Sm2+ phosphor particles provides a practical solution to general WLEDs lighting.

scholarly journals Employing SiO2 nano-particles in conformal and in-cup structures of 8500 K white LEDs

2021 ◽  
Vol 10 (3) ◽  
pp. 1709-1717
Author(s):  
My Hanh Nguyen Thi ◽  
Phung Ton That
Keyword(s):  
Blue Light ◽  
White Light ◽  
Sio2 Nanoparticles ◽  
Luminous Flux ◽  
Nano Particles ◽  
Color Temperature ◽  
Refractive Indices ◽  
Light Emitting ◽  
White Leds ◽  
White Light Emitting Diodes

SiO2 nano-particles have been examined in a distant phosphor structure for the elevated luminous quality and better consistency of white light-emitting diodes with angular-dependent associated color temperature (CCT). The luminous scattering ability could be increased by applying SiO2 nano-particles contain silicone to the outside of the phosphorus coating. In specific, the strength of blue light at wide angles is increased and differences in CCT can be minimized. In addition, owing to the sufficient refractive indices of silicone-containing SiO2 nanoparticles between the air and phosphorus layers, the luminous flux was improved. This new configuration decreases angular-dependent CCT deviations in the range of -700 to 700 from 1000 to 420 K. In comparison, at a 120 mA driving current, the rise of lumen flux increased by 2.25% relative to an usual distant phosphor structure without SiO2 nano-particles. As a result, in a distant phosphor structure, the SiO2 nano-particles could not only enhance the uniformity of illumination but also enhance the output of light.

scholarly journals Increasing Optical Performance of the 7000 K, 8500 K Remote Packaging WLEDs by the Red-emitting α-SrO·3B2O3:Sm2+ Conversion Phosphor

2018 ◽  
Vol 2 (1) ◽  
pp. 55
Author(s):  
Hoang Quang Minh Tran ◽  
Huu Khanh Nhan Nguyen ◽  
Hsiao-Yi Lee
Keyword(s):  
Luminous Flux ◽  
Color Temperature ◽  
Optical Performance ◽  
White Leds ◽  
Creative Commons ◽  
Color Quality ◽  
Quality Scale ◽  
Color Uniformity ◽  
Color Rendering ◽  
Open Access Article

In this paper, by mixing the red-emitting α-SrO·3B2O3:Sm2+ conversion phosphor to yellow-emitting YAG:Ce phosphor compound, an innovative recommendation for increasing optical performance of white LEDs (WLEDs) with remote packaging, which has an average correlated color temperature (CCT) of 700K and 8500K, is proposed and demonstrated. By varying α-SrO·3B2O3:Sm2+ concentration from 2% to 24 %, the obtained results indicated that color uniformity, color rendering index (CRI), color quality scale (CQS), and luminous flux could be improved significantly. The results demonstrated a prospective recommendation for manufacturing remote packaging phosphor 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 Highly Reliable and Low-Cost Fabrication of Warm-White LEDs Using Composite Silica Photonic Crystals

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chun-Feng Lai ◽  
Yu-Chun Lee ◽  
Tzong-Liang Tsai ◽  
Chung-Chieh Chang ◽  
Mau-Kuen Wu
Keyword(s):  
Photonic Crystals ◽  
Low Cost ◽  
Luminous Flux ◽  
Adhesion Properties ◽  
Light Emitting ◽  
White Leds ◽  
Colloidal Photonic Crystals ◽  
Curing Method ◽  
White Light Emitting Diodes ◽  
Inexpensive Technique

We demonstrated a technique requiring little phosphor that used white light-emitting diodes (WLEDs) containing composite silica colloidal photonic crystals (c-SCPhCs) for developing the warm-WLEDs (w-WLEDs). WLEDs containingc-SCPhCs enhanced luminous efficacy 5.6% more than commercialw-WLEDs did. We used a UV adhesive curing method to improve the adhesion properties of thec-SCPhCs. A reliability analysis (RA) test was performed on the WLEDs containingc-SCPhCs, applying a high temperature and high relative humidity (85°C/85 RH) during WLEDs operation at 120 mA. During a RA test of 2500 h, no visible degradation in optical performance was observed. We implemented a novel, inexpensive technique for producing high luminous fluxw-WLEDs that can be used in residential light.

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