Effects of Localized Heat Generations Due to the Color Conversion in Phosphor Particles and Layers of High Brightness Light Emitting Diodes
Effects of Localized Heat Generations Due to the Color Conversion in Phosphor Particles and Layers of High Brightness Light Emitting Diodes
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DOI：
10.1115/ipack2003-35015
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
M. Arik;S. Weaver;C. A. Becker;M. Hsing;A. Srivastava
中科院分区：
文献类型：
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作者：
M. Arik;S. Weaver;C. A. Becker;M. Hsing;A. Srivastava
固态照明设备的效率和可靠性在很大程度上取决于成功的热管理。发光二极管、LED是下一代通用照明应用的有力候选者。典型的白色LED从有源量子层产生的蓝色或近紫外光开始。光被引导通过填充了微米尺寸的荧光粉颗粒的透明密封剂。荧光粉颗粒将短波长光向上转换为所需的颜色，从而产生白色光。由于量子效率低，在转换过程中，会发生小粒子的局域加热。高亮度LED封装的实验结果表明，光输出显著减少。通过有限元技术建立了理想化的数值模型，以评估颗粒和层的局部热产生的影响。结果表明，在直径为20μm的球形荧光粉颗粒上，小至3 mW的发热量可能会导致过高的温度，这可能是高亮度LED输出光退化和可靠性问题的主要来源。
The efficiency and reliability of the solid-state lighting devices strongly depend on successful thermal management. Light emitting diodes, LEDs, a strong candidate for the next generation general illumination applications are of interest. Typical white LEDs start with either blue or near UV light generated by the active quantum layers. The light is guided through a transparent encapsulant filled with micron sized phosphor particles. The phosphor particles up-convert the short wavelength light to desired colors, producing white light. Due to low quantum efficiency, during the conversion, localized heating of small particles occurs. Experimental results with high brightness LED packages showed that there is significant light output reduction. Idealized numerical models through Finite element technique were created to evaluate the effects of localized heat generations at particles and layers. Results showed that as small as a 3 mW heat generation on a 20 μm diameter spherical phosphor particle might lead to excessive temperatures which can be a major source of light output degradation and reliability concern for high brightness LEDs.Copyright © 2003 by ASME