Self-adaptive phosphor coating technology for white LED packaging

doi:10.1007/s12200-012-0236-3

Front Optoelec

2012, Vol. 5

Issue (2) : 147-152 https://doi.org/10.1007/s12200-012-0236-3

Research Article

Self-adaptive phosphor coating technology for white LED packaging

Haibo RAO(

), Kun DING, Jirong SONG, Likun XIE, Wei WANG, Xianlong WAN, Linsong ZHOU, Junyuan LIAO

School of Opto-electronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China

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Abstract

Phosphor-converted light-emitting diodes (pc-LEDs), which employ blue LEDs with yellow phosphors to generate white light illumination, is a widely used solid-state lighting source. In order to conduct a phosphor layer coating with high quality on LED chip, a self-adaptive coating technology is introduced in this paper. A slurry coating technique combined with self-exposure method is applied and developed to demonstrate the benefits of self-adaptive coating layer. For self-exposure, the slurry coating is exposed to the blue emission of LED itself other than to ultraviolet (UV) light outside to make photoresist crosslinking. Results of measurement indicate that white LEDs with self-adaptive coating have shown self-adaptability to the angular distribution of intensity of blue light and performed higher spatial color uniformity than those with conventional coating and other conformal coating.

Keywords white light-emitting diodes (LEDs) phosphor coating self-adaptive slurry method self-exposure

Corresponding Author(s): RAO Haibo,Email:rhb@uestc.edu.cn

Issue Date: 05 June 2012

Cite this article:

Haibo RAO,Kun DING,Jirong SONG, et al. Self-adaptive phosphor coating technology for white LED packaging[J]. Front Optoelec, 2012, 5(2): 147-152.

URL:

https://academic.hep.com.cn/foe/EN/10.1007/s12200-012-0236-3
https://academic.hep.com.cn/foe/EN/Y2012/V5/I2/147

Fig.1 Schematic diagrams of different coating configuration.
(a) Conventional coating; (b) conformal coating; (c) remote coating

Fig.2 Measured BTDFs of (a) emitted yellow-light radiance and (b) scattered blue-light radiance []

Fig.3 Schematic diagram of slurry coating process with self-exposure.
(a) Blue LED; (b) phosphor coating; (c) exposure; (d) develop

Fig.4 White light pictures of white LEDs with different coating techniques.
(a) With self-exposure conformal coating; (b) with self-exposure remote phosphor coating; (c) with conventional phosphor coating; (d) commercial conformal coating product

Fig.5 Chromaticity distributions of white LEDs with different coating layer.
(a) ; (b) . a: With self-exposure conformal coating; b: with self-exposure remote phosphor coating; c: with conventional phosphor coating; d: commercial conformal coating product

Fig.6 Picture of white pc-LED with self-adaptive phosphor coating

Fig.7 Picture of white pc-LED array with self-adaptive phosphor coating

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