scholarly journals Micro-Prism Patterned Remote Phosphor Film for Enhanced Luminous Efficiency and Color Uniformity of Phosphor-Converted Light-Emitting Diodes

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1117
Author(s):  
Jiadong Yu ◽  
Shudong Yu ◽  
Ting Fu ◽  
Yong Tang
Keyword(s):  
Light Emitting Diodes ◽  
Color Stability ◽  
Luminous Flux ◽  
Luminous Efficiency ◽  
Light Emitting ◽  
Exit Surface ◽  
Roll To Roll ◽  
Color Uniformity ◽  
Remote Phosphor ◽  
Phosphor Film

In this work, we propose micro-prism patterned remote phosphor (RP) films to enhance both luminous efficiency and color uniformity (CU) of remote phosphor-converted light-emitting diodes (rpc-LEDs) simultaneously. On the incident surface of the RP film, one micro-prism film is used to extract backward light by double reflection. On the exit surface, the other micro-prism film is adopted to retain blue light inside the RP film, thus enhancing the phosphor excitation. Experimental results show that double prism-patterned RP (DP-RP) film configuration shows a luminous flux of 55.16 lm, which is 45.1% higher than that of RP film configuration at 300 mA. As regards the CU, the DP-RP film configuration reduces the angular CIE-x and CIE-y standard variations by 68% and 69.32%, respectively, compared with the pristine device. Moreover, the DP-RP film configuration shows excellent color stability under varying driving currents. Since micro-prism films can be easily fabricated by a roll-to-roll process, the micro-prism patterned RP film can be an alternative to a conventional RP layer to enable the practical application of rpc-LEDs.

Improvement in optical performance and color uniformity by optimizing the remote phosphor caps geometry for chip-on-board light emitting diodes

2016 ◽  
Vol 126 ◽  
pp. 36-45 ◽  
Author(s):  
Jiasheng Li ◽  
Zongtao Li ◽  
Zhi Li ◽  
Yong Tang ◽  
Xinrui Ding ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Optical Performance ◽  
Light Emitting ◽  
Color Uniformity ◽  
Remote Phosphor

Angular color uniformity enhancement of white light-emitting diodes by remote micro-patterned phosphor film

2016 ◽  
Vol 4 (4) ◽  
pp. 140 ◽  
Author(s):  
Shudong Yu ◽  
Zongtao Li ◽  
Guanwei Liang ◽  
Yong Tang ◽  
Binhai Yu ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Color Uniformity ◽  
Phosphor Film ◽  
White Light Emitting Diodes

scholarly journals Applying SiO2 nano-particles for improving optical properties of WLED conformal and in-cup structures

2021 ◽  
Vol 10 (4) ◽  
pp. 1914-1922
Author(s):  
Phan Xuan Le ◽  
Pham Quang Minh
Keyword(s):  
Luminous Flux ◽  
Luminous Efficiency ◽  
Nano Particles ◽  
Color Temperature ◽  
Temperature Uniformity ◽  
Phosphor Layer ◽  
Temperature Deviation ◽  
Color Uniformity ◽  
Remote Phosphor ◽  
Index Ratio

This article is the analysis of SiO2 nano-particles’ influences on the luminous efficiency and the color temperature uniformity of a remote phosphor structure in a WLED. The purpose of integrating SiO2 into the silicone layer in the remote phosphor structure is to significantly promote the scattering occurrences. Particularly, with an appropriate proportion of SiO2, there could be more blue lights generated at large angles, leading to reducing the angular-dependent color temperature deviation. The luminous flux also can get benefits from SiO2 addition owing to a proper air-phosphor layer refractive index ratio provided by this SiO2/silicone compound. The attained experimental results were compared with optical values of a non-SiO2 remote phosphor configuration and showed a notable enhancement. The color deviation was reduced by approximately 600 K in the angles from -700 ­to 700. Additionally, the lumen efficiency was improved by 2.25% at 120 mA driving current. Hence, SiO2 can be used to boost both color uniformity and luminous efficacy for remote-phosphor WLED.

Enhancement of angular color uniformity of remote-phosphor-converted light-emitting diodes by electrospun-nanofiber diffusing films

2018 ◽  
Vol 227 ◽  
pp. 104-107 ◽  
Author(s):  
Yong Tang ◽  
Guanwei Liang ◽  
Cunjiang Song ◽  
Zongtao Li ◽  
Shudong Yu ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Electrospun Nanofiber ◽  
Light Emitting ◽  
Color Uniformity ◽  
Remote Phosphor

scholarly journals Eu2+-activated strontium-barium silicate: a positive solution for improving luminous efficacy and color uniformity of white light-emitting diodes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
My Hanh Nguyen Thi ◽  
Phung Ton That ◽  
Nguyen Doan Quoc Anh
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Luminous Flux ◽  
Strontium Barium ◽  
Light Emitting ◽  
Barium Silicate ◽  
Color Uniformity ◽  
Suitable Amount ◽  
Enhancement Method ◽  
The Impact

Abstract In this research we have studied the lighting enhancement method by analyzing chromatic performance and luminous flux of light emitting diodes that produce white light. In order to achieve expected results, it is necessary to mix Eu2+-activated strontium-barium silicate (SrBaSiO4:Eu2+) with its phosphor compounding, which has been demonstrated to have considerable influence on lighting performance. The results showed that with the gradually increasing concentration of yellow-green-emitting SrBaSiO4:Eu2+ phosphor in LEDs devices, at 8500 K, the color homogeneity and the lighting output received a great improvement. The color quality scale, on the other hand, responded negatively to the increase in SrBaSiO4:Eu2+. The impact of SrBaSiO4:Eu2+ on optical properties of WLEDs was confirmed. The final step to optimize SrBaSiO4:Eu2+ usage in lighting development is to figure out a suitable amount of particles and optimize their size.

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.

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