A Model for Calculating the Bidirectional Scattering Properties of Phosphor Layer in White Light-Emitting Diodes

2012 ◽  
Vol 30 (21) ◽  
pp. 3376-3380 ◽  
Author(s):  
Run Hu ◽  
Xiaobing Luo
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Phosphor Layer ◽  
Light Emitting ◽  
White Light Emitting Diodes

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.

Color Uniformity Enhancement of White Light-Emitting Diodes With Novel Bell Shape Phosphor Layer

2017 ◽  
Author(s):  
Xingjian Yu ◽  
Weicheng Shu ◽  
Bofeng Shang ◽  
Bin Xie ◽  
Yanhua Cheng ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Color Temperature ◽  
Phosphor Layer ◽  
Spherical Cap ◽  
Light Emitting ◽  
Vof Model ◽  
Color Uniformity ◽  
Coating Method ◽  
White Light Emitting Diodes

In this study, we proposed a bell shape phosphor layer geometry and the corresponding dual-step phosphor coating method for enhancing the angular color uniformity (ACU) of phosphor-converted white light-emitting diodes (pcLEDs). Numerical simulation based on Volume of Fluid (VOF) model was applied to predict phosphor geometries. Based on the simulated results, experiments were conducted to realize the phosphor geometries. The simulated results show that the VOF model can predict the phosphor geometries with an acceptable geometric deviation within 5%. The experimental results show that compared with the spherical cap phosphor layer geometry, the bell shape geometry can achieve better ACU performance, an optimal bell phosphor layer geometry with equal coating volume above and around the LED chip was achieved, for the corrected color temperature (CCT) of 4000 K, the angular CCT deviation of the optimal geometry is 62 K, while it is 382 K for the spherical cap geometry.

High-temperature (350°C) glass phosphor layer for converted white light-emitting diodes

2012 ◽  
Author(s):  
Wood-Hi Cheng ◽  
Chun-Chin Tsai ◽  
Wei-Chih Cheng ◽  
Jin-Kai Chang ◽  
Ji-Hung Chen ◽  
...  
Keyword(s):  
High Temperature ◽  
White Light ◽  
Light Emitting Diodes ◽  
Phosphor Layer ◽  
Light Emitting ◽  
Glass Phosphor ◽  
White Light Emitting Diodes

Ultra-High Thermal-Stable Glass Phosphor Layer for Phosphor-Converted White Light-Emitting Diodes

2013 ◽  
Vol 9 (6) ◽  
pp. 427-432 ◽  
Author(s):  
Chun-Chin Tsai ◽  
Wei-Chih Cheng ◽  
Jin-Kai Chang ◽  
Li-Yin Chen ◽  
Ji-Hung Chen ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Phosphor Layer ◽  
Light Emitting ◽  
Stable Glass ◽  
Glass Phosphor ◽  
White Light Emitting Diodes ◽  
Thermal Stable
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