Abstract Light-emitting diodes (LEDs) are widely used in our daily lives. Both light and heat are generated from LED chips and then transmitted or conducted through multiple packaging materials and interfaces. Part of the transmitted light converts into heat along the light propagation; in return, the accumulation of heat leads to the degradation of light output. The accumulated heat negatively influences the reliability and longevity of LEDs, and thus thermal management is critical for LED packaging and applications. On the other hand, in LED packaging processes, many fluid flow problems exist, such as phosphor coating, silicone injection, chip bonding, solder reflow, etc. Among them, phosphor coating is the most important process which is essential for LED performance. Phosphor gel is a kind of non-Newton fluid and its coating process is a typical fluid-flow problem. Overall, since LED packaging and applications present many heat and fluid flow problems, obtaining a full understanding of these problems enables advancements in the development of LED processes and designs. In this review, the emphasis is placed on heat generation in chips, heat flow in packages and application products, fluid flow in phosphor coating process, etc. This is a domain in which significant progress has been achieved in the last decade, and reporting on these advances will facilitate state-of-the-art LED packaging and application technologies.

中文翻译：

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大功率 LED 封装和应用中的热量和流体流动

摘要 发光二极管 (LED) 广泛应用于我们的日常生活中。LED芯片产生光和热，然后通过多种封装材料和接口传输或传导。部分透射光沿光传播转化为热量；作为回报，热量的积累会导致光输出下降。累积的热量会对 LED 的可靠性和寿命产生负面影响，因此热管理对于 LED 封装和应用至关重要。另一方面，在LED封装工艺中，存在许多流体流动问题，如荧光粉涂层、硅胶注射、芯片键合、回流焊等。其中，荧光粉涂层是最重要的工艺，对LED性能至关重要。荧光凝胶是一种非牛顿流体，其涂覆过程是典型的流体流动问题。总体而言，由于 LED 封装和应用存在许多热和流体流动问题，因此充分了解这些问题可以促进 LED 工艺和设计的发展。在本次审查中，重点放在芯片发热、封装和应用产品中的热流、荧光粉涂层工艺中的流体流动等。 这是过去十年取得重大进展的领域，并报告了这些进步将促进最先进的 LED 封装和应用技术。对这些问题的全面了解有助于推动 LED 工艺和设计的发展。在本次审查中，重点放在芯片发热、封装和应用产品中的热流、荧光粉涂层工艺中的流体流动等。 这是过去十年取得重大进展的领域，并报告了这些进步将促进最先进的 LED 封装和应用技术。对这些问题的全面了解有助于推动 LED 工艺和设计的发展。在本次审查中，重点放在芯片发热、封装和应用产品中的热流、荧光粉涂层工艺中的流体流动等。 这是过去十年取得重大进展的领域，并报告了这些进步将促进最先进的 LED 封装和应用技术。