Process development for yellow phosphor coating on blue light emitting diodes (LEDs) for white light illumination

2006 ◽  
Author(s):  
K. Lee ◽  
S.W. Lee
Keyword(s):  
Blue Light ◽  
White Light ◽  
Light Emitting Diodes ◽  
Process Development ◽  
Light Illumination ◽  
Light Emitting ◽  
Yellow Phosphor ◽  
Phosphor Coating ◽  
White Light Illumination

Screen-Printing of Yellow Phosphor Powder on Blue Light Emitting Diode (LED) Arrays for White Light Illumination

2007 ◽  
Author(s):  
K. H. Lee ◽  
S. W. Ricky Lee
Keyword(s):  
White Light ◽  
Screen Printing ◽  
Light Emitting Diode ◽  
Light Illumination ◽  
Light Emitting ◽  
Yellow Phosphor ◽  
Coating Methods ◽  
Phosphor Coating ◽  
White Light Illumination ◽  
Led Arrays

In current technology, white light generation from a light emitting diode (LED) can be achieved by combining the lights from three fundamental colors, namely, red, green and blue (RGB), of LEDs or by coating a phosphor layer onto the surface of a LED chip. The first method involving the RGB color mixing technique requires a complicated electrical circuit design for the control of light intensity and uniformity on the three different colors of LEDs and hence increases the costs of manufacturing. The second method is implemented by coating a layer of yellow phosphor on a blue LED chip for white light illumination. The quality of generated white light heavily depends on the packing density, the thickness and the uniformity of the phosphor coating. There have been some coating methods available in the industry. Each one of them has its own pros-n-cons. In the present study, a new yellow phosphor coating method by screen-printing on blue LED arrays is developed. Compared with conventional coating methods, this screen-printing method is considered relatively simple and rather effective. The newly developed method and the results of prototyping are introduced in this paper in detail.

(K0.5Na0.5)NbO3:Eu3+/Bi3+: a novel, highly efficient, red light-emitting material with superior water resistance behavior

RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4707-4715 ◽  
Author(s):  
Qiwei Zhang ◽  
Haiqin Sun ◽  
Tao Kuang ◽  
Ruiguang Xing ◽  
Xihong Hao
Keyword(s):  
Blue Light ◽  
White Light ◽  
High Performance ◽  
Water Resistance ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Light Emitting ◽  
Highly Efficient ◽  
White Light Emitting Diodes

Materials emitting red light (∼611 nm) under excitation with blue light (440–470 nm) are highly desired for fabricating high-performance white light-emitting diodes (LEDs).

A novel green phosphor LaMgAl11O19:Ho3+ for near-UV/blue light-pumped white light-emitting diodes

2015 ◽  
Vol 618 ◽  
pp. 182-185 ◽  
Author(s):  
Xin Min ◽  
Minghao Fang ◽  
Zhaohui Huang ◽  
Hao Liu ◽  
Yan’gai Liu ◽  
...  
Keyword(s):  
Blue Light ◽  
White Light ◽  
Light Emitting Diodes ◽  
Green Phosphor ◽  
Light Emitting ◽  
White Light Emitting Diodes

Influence of blue-light polarization on light scattering in nanocrystal luminescent glass for white light-emitting-diodes

2010 ◽  
Vol 6 (3) ◽  
pp. 164-167 ◽  
Author(s):  
Hong-guo Li ◽  
Ying-tao Zhang ◽  
Ding Zhong ◽  
Suo-cheng Xu ◽  
Qin-ni Fei ◽  
...  
Keyword(s):  
Light Scattering ◽  
Blue Light ◽  
White Light ◽  
Light Emitting Diodes ◽  
Light Polarization ◽  
Light Emitting ◽  
White Light Emitting Diodes

scholarly journals Performance Improvement of GaN-Based Flip-Chip White Light-Emitting Diodes with Diffused Nanorod Reflector and with ZnO Nanorod Antireflection Layer

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Hsin-Ying Lee ◽  
Yu-Chang Lin ◽  
Yu-Ting Su ◽  
Chia-Hsin Chao ◽  
Véronique Bardinal
Keyword(s):  
Blue Light ◽  
White Light ◽  
Flip Chip ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Nanorod Array ◽  
Zno Nanorod ◽  
Light Emitting ◽  
Zno Nanorod Array ◽  
White Light Emitting Diodes

The GaN-based flip-chip white light-emitting diodes (FCWLEDs) with diffused ZnO nanorod reflector and with ZnO nanorod antireflection layer were fabricated. The ZnO nanorod array grown using an aqueous solution method was combined with Al metal to form the diffused ZnO nanorod reflector. It could avoid the blue light emitted out from the Mg-doped GaN layer of the FCWLEDs, which caused more blue light emitted out from the sapphire substrate to pump the phosphor. Moreover, the ZnO nanorod array was utilized as the antireflection layer of the FCWLEDs to reduce the total reflection loss. The light output power and the phosphor conversion efficiency of the FCWLEDs with diffused nanorod reflector and 250 nm long ZnO nanorod antireflection layer were improved from 21.15 mW to 23.90 mW and from 77.6% to 80.1% in comparison with the FCWLEDs with diffused nanorod reflector and without ZnO nanorod antireflection layer, respectively.

Self-Adaptive Conformal–Remote Phosphor Coating of Phosphor-Converted White Light Emitting Diodes

2016 ◽  
Vol 12 (9) ◽  
pp. 946-950 ◽  
Author(s):  
Caineng Li ◽  
Haibo Rao ◽  
Wei Zhang ◽  
Chunyu Zhou ◽  
Qi Zhang ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Remote Phosphor ◽  
Phosphor Coating ◽  
White Light Emitting Diodes ◽  
Self Adaptive

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.

Improved Yellow Light Emission in the Achievement of Dichromatic White Light Emitting Diodes

2013 ◽  
Vol 1538 ◽  
pp. 371-375
Author(s):  
Zhao Si ◽  
Tongbo Wei ◽  
Jun Ma ◽  
Ning Zhang ◽  
Zhe Liu ◽  
...  
Keyword(s):  
Blue Light ◽  
White Light ◽  
Light Emitting Diodes ◽  
Light Emission ◽  
Dual Wavelength ◽  
Emission Wavelength ◽  
White Led ◽  
Yellow Light ◽  
Light Emitting ◽  
White Light Emitting Diodes

ABSTRACTA study about the achievement of dichromatic white light-emitting diodes (LEDs) was performed. A series of dual wavelength LEDs with different last quantum-well (LQW) structure were fabricated. The bottom seven blue light QWs (close to n-GaN layer) of the four samples were the same. The LQW of sample A was 3 nm, and that of sample B, C and D were 6 nm, a special high In content ultra-thin layer was inserted in the middle of the LQW of sample C and on top of that of sample D. XRD results showed In concentration fluctuation and good interface quality of the four samples. PL measurements showed dual wavelength emitting, the blue light peak position of the four samples were almost the same, sample A with a narrower LQW showed an emission wavelength much shorter than that of sample B, C, D. EL measurement was done at an injection current of 100 mA. Sample A only showed LQW emission due to holes distribution. Because of wider LQW, the emission wavelength of sample B, C and D was longer and peak intensity was weaker. Sample D with insert layer on top of LQW showed strongest yellow light emission with a blue peak. As the injection current increased, sample A showed highest output light power due to narrower LQW. Of the other three samples with wider LQW, sample D showed highest output power. Effective yellow light emission has always been an obstacle to the achievement of dichromatic white LED. Sample D with insert layer close to p-GaN can confine the hole distribution more effectively hence the recombination of holes and electrons was enhanced, the yellow light emission was improved and dichromatic white LED was achieved.

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