Dip-transfer phosphor coating on designed substrate structure for high angular color uniformity of white light emitting diodes with conventional chips

Zheng, Hao; Wang, Yiman; Li, Lan; Fu, Xing; Zou, Yonggang; Luo, Xiaobing

doi:10.1364/oe.21.00a933

Cited by 28 publications

(8 citation statements)

References 20 publications

(28 reference statements)

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“…Zhang和 Lee [130] 通过在基板上加工微槽来限制封装胶的流动, 从而得到和基板之间具有较大接触角的晶圆级荧光粉涂覆方法; Yu等人 [131] [117,118,134,135] . 针对于扩展光源, Munon等人 [137] 和Benitez等人 [138] 于2004年提出多曲面同时设计法 ( [154] . (a) 传统基板及其荧光粉胶形貌; (b) 带方形凸台基板及其荧光粉胶层形貌; (c) 带方形凸台基板的荧光粉胶层在不同CCT下的空间颜色均匀性间颜色均匀性的改进效果如图32(c)所示, 在CCT为 4000~6000 K之间实现空间CCT偏差小于200 K. Sun等人 [155] [159] .…”

Section: 理论上光子晶体可以将芯片的出光效率提高到90%以unclassified

LED packaging for high light quality: Status and perspectives

Yu¹,

Shu²,

Hu³

et al. 2017

Sci. Sin.-Tech.

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Section: 理论上光子晶体可以将芯片的出光效率提高到90%以unclassified

LED packaging for high light quality: Status and perspectives

Yu¹,

Shu²,

Hu³

et al. 2017

Sci. Sin.-Tech.

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“…In the traditional pc-LEDs, the scattering of phosphor is itself an effective way to realize the ACU improvement. Moreover, changing the morphology of the phosphor layer by different processing methods to make optical path of blue light consistent at all viewing angles is an effective way to realize the ACU improvement [9]- [11]. Adding nano/micro particles in the phosphor layer to enhance light scattering is also a simple method to improve ACU [12]- [14].…”

Section: Introductionmentioning

confidence: 99%

Angular Color Uniformity Enhancement for Color-Mixed LEDs by Introducing a Diffusing Coating Layer

et al. 2020

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In this study, a simple and low-cost method is proposed to enhance angular color uniformity (ACU) of color-mixed light-emitting diodes (cm-LEDs) by introducing a diffuse coating layer. Optical models of the proposed cm-LEDs packaging modules were constructed by Monte Carlo ray-tracing simulation. The simulation results demonstrate the ACU enhancement of the cm-LEDs packaging modules with the application of the diffuse coating layer on the reflection cup. Owing to the strong light scattering and diffuse reflection effects of the diffuse coating layer, the different color light emitted from the different chip are sufficiently mixed. The diffuse coating layer was fabricated by spraying method. Its optical performance was demonstrated by experiments. The correlated color temperature (CCT) deviations of the cm-LEDs applying the diffuse coating layer have been reduced from 1174 K to 138 K at viewing angles ranging from −80°to +80°. A lowest luminous flux loss of 3.54% is obtained. The diffuse coating layer could also maintain the excellent ACU performance when the average CCTs changes from about 2000 K to 5200 K. Extremely low CCT deviations were obtained, which are less than 300 K at average CCTs ranging from 2000 K to 5200 K. The results demonstrate that the diffuse coating layer is a feasible and effective method to enhance the ACU of the cm-LEDs.

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“…In addition, the geometry of the phosphor gel is a big spherical cap by direct liquid dispensing, consequently lead to a low ACU. Recently, Zheng et al presented a phosphor dip-transfer coating method to realize high ACU for phosphor-converted white LEDs [10,11]. Dip coating is a common method and extensively applied in some industries because of its simplicity and high throughput [12].…”

Section: Introductionmentioning

confidence: 99%

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

Shang

Zheng

et al. 2016

Journal of Electronic Packaging

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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.

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Dip-transfer phosphor coating on designed substrate structure for high angular color uniformity of white light emitting diodes with conventional chips

Cited by 28 publications

References 20 publications

LED packaging for high light quality: Status and perspectives

LED packaging for high light quality: Status and perspectives

Angular Color Uniformity Enhancement for Color-Mixed LEDs by Introducing a Diffusing Coating Layer

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

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