scholarly journals A 4.7-inch-Diagonal TFEL Display with SrS:Ce, Eu White Light Emitting Phosphor Layer.

1993 ◽  
Vol 47 (5) ◽  
pp. 702-707
Author(s):  
Yoshito Tanaka ◽  
Sadae Yamada ◽  
Maki Minamoto ◽  
Yuji Fujita ◽  
Tsuneo Konishi
Keyword(s):  
White Light ◽  
Phosphor Layer ◽  
Light Emitting

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.

Cylindrical Tuber Encapsulant Layer Realization by Patterned Surface for Chip-on-Board Light-Emitting Diodes Packaging

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Xingjian Yu ◽  
Run Hu ◽  
Ruikang Wu ◽  
Bin Xie ◽  
Xiaoyu Zhang ◽  
...  
Keyword(s):  
Blue Light ◽  
White Light ◽  
Light Emitting Diodes ◽  
Composite Layer ◽  
Color Temperature ◽  
Efficiency Enhancement ◽  
Phosphor Layer ◽  
Light Emitting ◽  
Nanosilica Particles ◽  
Light Efficiency

In this study, we realized a cylindrical tuber silicone layer for improving the light efficiency of chip-on-board light-emitting diodes (COB-LEDs) by fabricating patterned LED substrate with both silicone-wetting and silicone-repellency surfaces. To realize silicone-repellency surface, low surface energy modified nanosilica particles were prepared and deposited on the LED substrate to form porous hierarchical structure. Light efficiency enhancement for blue light COB-LEDs with pure cylindrical tuber silicone layer and white light COB-LEDs with phosphor–silicone composite layer was studied. The results show that for blue light COB-LEDs with pure cylindrical tuber silicone layer, the light efficiency increases with the contact angle and a highest light efficiency enhancement of 62.6% was achieved at 90 deg when compared to the flat silicone layer. For white light COB-LEDs at correlated color temperature (CCT) of ∼5500 K, the cylindrical tuber silicone layer enhances the light efficiency by 13.6% when compared to the conventional flat phosphor layer.

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.

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