scholarly journals Y2O3:Ho3+ and ZnO:Bi3+: a selection for enhancing color quality and luminous flux of WLEDs

2020 ◽  
Vol 10 (5) ◽  
pp. 5162
Author(s):  
Nguyen Thi Phuong Loan ◽  
Nguyen Doan Quoc Anh
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Luminous Flux ◽  
Configuration Model ◽  
Single Chip ◽  
Luminous Efficacy ◽  
Light Emitting ◽  
Color Quality ◽  
Color Rendering ◽  
Research Show

As the luminescence industry develops, the white light light-emitting diode (LED) package with a single chip and a single phosphor although produces good luminous flux but has a poor color rendering index (CRI) can no longer fulfill the requirements of modern lighting applications. Therefore, this research is conducted to response to the urgent demands of improving other lighting qualities of WLED while maintaining high luminous efficiency. To achieve this target, we applied the new WLED package, which contains multi-chips and multi-phosphor layers, and have obtained outstanding results in both CRI and luminous efficacy. Two types of phosphor used in the WLED package are Y2O3:Ho3+ and ZnO:Bi3+. A color configuration model is also developed to adjust the shading of the white-light LED module. The results of this research show that the triple-layer phosphorhas the best performance when applied in a white-light LED package, which is demonstrated through better color quality, CRI and luminous efficacy, The manufacturers can rely on this research to produce the optimal-quality WLED, or WLED that is appropriate to their quality demands.

scholarly journals Composition and structure design of three-layered composite phosphors for high color rendering chip-on-board light-emitting diode devices

2021 ◽  
Author(s):  
Xin Liu ◽  
Xinglu Qian ◽  
Peng Zheng ◽  
Xiaopu Chen ◽  
Yagang Feng ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Layered Composite ◽  
Structure Design ◽  
Color Temperature ◽  
Vacuum Sintering ◽  
Luminous Efficacy ◽  
Light Emitting ◽  
Composition And Structure ◽  
Color Rendering

AbstractA three-layered phosphor structure was designed and prepared by the spin coating of BaSi2N2O2:Eu (cyan-emitting) and (Sr,Ca)AlSiN3:Eu (red-emitting) phosphor films on the yellow-emitting Y3Al5O12:Ce (YAG:Ce) phosphor ceramic synthesized by the solid-state reaction under vacuum sintering. In order to achieve high color rendering lighting, the influence of the composition and structure of the three-layered phosphors on the optical, thermal, and electrical properties of the chip-on-board (COB) packaged white-light-emitting diodes (WLEDs) was studied systematically. The WLED with the structure of “red+cyan+yellow” (R+C+Y) three-layered phosphor generated neutral white light and had a luminous efficacy of 75 lm/W, the fidelity index (Rf) of 93, the gamut index (Rg) of 97, and the correlated color temperature (CCT) of 3852 K. Under the excitation of laser diode (LD), the layer-structured phosphor yielded the white light with a luminous efficacy of 120 lm/W, color rendering index (CRI) of 90, and CCT of 5988 K. The result indicates that the three-layered phosphor structure is a promising candidate to achieve high color rendering and high luminous efficacy lighting.

scholarly journals Using CaCO3-doped package to improve correlated color temperature uniformity of white light-emitting diodes

2021 ◽  
Vol 11 (6) ◽  
pp. 4817
Author(s):  
My Hanh Nguyen Thi ◽  
Nguyen Thi Phuong Loan ◽  
Thuc Minh Bui ◽  
Hoang Van Ngoc
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Luminous Flux ◽  
Color Temperature ◽  
Resin Matrix ◽  
Light Emitting ◽  
Color Quality ◽  
Color Uniformity ◽  
Stability Enhancement ◽  
White Light Emitting Diodes

<span>The white light-emitting diode (WLED) has been the most advance lighting method currently, however, the fabrication process of this configuration still has drawbacks which negatively affect its color quality. This research was conducted to provide a method for WLED’s lighting output enhancement. Since CaCO<sub>3</sub> particles are excellent for thermal stability enhancement, especially when being combined with an adhesive substance, we decided to integrate CO<sub>3</sub> particles into resin matrix such as melamine formaldehyde (MF) and investigate their influences on the optical properties, including color uniformity and lumen output, of the WLED. The results showed that CaCO3 and MF resin are beneficial to the light scattering efficiency, which results in higher luminous flux and chromatic quality for WLED packages. In addition to that, the appropriate amounts of MF resin and CaCO<sub>3</sub> for reaching the best lumen efficiency and color quality are figured out at 1% and 10%, respectively. Moreover, another advantage of using MF resin and CaCO<sub>3</sub> for fabricating WLEDs is cost effectiveness. Hence, it has turned out that CaCO<sub>3</sub> and MF resins can be potential materials for next high-quality WLED generations.</span>

scholarly journals (Y,Gd)BO3:Eu red phosphor for dual-layer phosphor structure to enhance the optical performance of white light-emitting diodes

2021 ◽  
Vol 10 (4) ◽  
pp. 1930-1935
Author(s):  
Phan Xuan Le ◽  
Le Hung Tien
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Phosphor Layer ◽  
Light Emitting ◽  
Conformal Coating ◽  
Color Quality ◽  
Remote Phosphor ◽  
White Light Emitting Diodes ◽  
Color Rendering

Among the structures using for fabricating white light-emitting diodes (WLEDs) such as the conformal coating or in-cup geometries, the remote phosphor structure gives the highest luminous efficacy. However, in terms of color quality, its performance is not as good as the others. The red-light compensation has been reported as the effective solution for enhancing the color quality of WLEDs. Hence, this study adopted the idea and applied to the dual-layer phosphor structure. The phosphor used to boost the red color in light formation is (Y,Gd)BO3:Eu particle. The dual-layer remote phosphor structure was simulated with the red (Y,Gd)BO3:Eu phosphor layer above the original yellow phosphor YAG:Ce3+ one. The WLEDs with different correlated color temperatures of 5600 K, 6600 K and 7700K were experimented. Mie-theory and Lambert-Beer law were applied to examine the results. The growth in color rendering index (CRI) and color quality scale (CQS) with the increase of (Y,Gd)BO3:Eu phosphor concentration was observed. Nevertheless, the lumen efficacy would be degraded if the concentration was over a certain number. The information provided in this article is useful for the development of high-power WLED production with greater color quality.

scholarly journals Chromaticity Study of Curcumin Dye Extracted from Curcuma longa L. Using for UV Light down Conversion for White Light Emitting Diode

2019 ◽  
Vol 290 ◽  
pp. 183-189
Author(s):  
Mahmood Al Shafouri ◽  
Naser Mahmoud Ahmed ◽  
Zainuriah Hassan ◽  
Munirah Abdullah Almessiere
Keyword(s):  
White Light ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Curcuma Longa ◽  
Color Temperature ◽  
Light Emitting ◽  
Chromaticity Coordinates ◽  
Major Factors ◽  
Color Rendering ◽  
Down Conversion

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

Utilization of LiSrPO4:Eu phosphor and CuInS quantum dot for fabrication of high color rendering white light-emitting diode

2013 ◽  
Vol 92 ◽  
pp. 325-329 ◽  
Author(s):  
Woo-Seuk Song ◽  
Jong-Hoon Kim ◽  
Jeong-Hoon Lee ◽  
Hye-Seung Lee ◽  
Ho Seong Jang ◽  
...  
Keyword(s):  
Quantum Dot ◽  
White Light ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Color Rendering
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