Research Papers

Numerical and Experimental Study on the Transferred Volume in Phosphor Dip-Transfer Coating Process of Light-Emitting Diodes Packaging

[+] Author and Article Information
Bofeng Shang

School of Energy and Power Engineering,
Huazhong University of Science and Technology,
Wuhan 430074, China
e-mail: shangbofeng_hust@163.com

Xingjian Yu

School of Energy and Power Engineering,
Huazhong University of Science and Technology,
Wuhan 430074, China
e-mail: yuxingjian_hust@163.com

Huai Zheng

School of Energy and Power Engineering,
Huazhong University of Science and Technology,
Wuhan 430074, China
e-mail: huai_zheng@whu.edu.cn

Bin Xie

School of Energy and Power Engineering,
Huazhong University of Science and Technology,
Wuhan 430074, China
e-mail: xiebinhust@163.com

Qi Chen

School of Energy and Power Engineering,
Huazhong University of Science and Technology,
Wuhan 430074, China
e-mail: cooche@hust.edu.cn

Xiaobing Luo

School of Energy and Power Engineering,
Huazhong University of Science and Technology,
Wuhan 430074, China
e-mail: luoxb@hust.edu.cn

1Corresponding author.

Contributed by the Electronic and Photonic Packaging Division of ASME for publication in the JOURNAL OF ELECTRONIC PACKAGING. Manuscript received June 17, 2015; final manuscript received March 15, 2016; published online April 19, 2016. Assoc. Editor: Shi-Wei Ricky Lee.

J. Electron. Packag 138(2), 021003 (Apr 19, 2016) (5 pages) Paper No: EP-15-1057; doi: 10.1115/1.4033165 History: Received June 17, 2015; Revised March 15, 2016

The phosphor dip-transfer coating method is simple and flexible for transferring a pre-analyzed volume of phosphor gel, which can be beneficial to the high angular color uniformity (ACU) of white light-emitting diodes (LEDs). The crux of this method is the volume control of the phosphor gel; however, the critical factors which influence the volume control remain unrevealed. In this paper, we concentrate on investigating the transferred volume in terms of three parameters: withdrawal speed, post radius, and dipping depth. Numerical simulations were carried out utilizing the volume of fluid (VOF) model combined with the dynamic mesh model. The experiments were also conducted on an optical platform equipped with a high-speed camera. The simulation results coincide well with the experimental results, with the maximum relative difference within 15%. The results show that the transferred volume increases with the increasing withdrawal speed and remains stable when the speed is greater than 1 mm/s, and it shows a linear relationship with the cube of post radius. And the transferred volume will increase with the dipping depth. Based on the experimental and numerically work, it is concluded that the volume of the pre-analyzed phosphor gel can be precisely obtained.

Copyright © 2016 by ASME
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Grahic Jump Location
Fig. 1

Schematics of phosphor dip-transfer coating. (a) Dipping the post into the mixture. (b)–(d) Drawing the post with a predefined speed.

Grahic Jump Location
Fig. 2

Physical model of numerical simulation

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Fig. 3

Schematic of the experimental setup

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Fig. 4

The phosphor gel geometry changes over time during dip-transfer process. (a) Experiment results and (b) numerical simulation results.

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Fig. 5

The transferred volume varies with the variation of withdrawal speed

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Fig. 6

The transferred volume varies with the variation of r3

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Fig. 7

The transferred volume varies with the variation of dipping depth




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