Abstract Light-emitting diodes (LEDs) have become a promising solid-state light source in numerous applications. During operation, they are often exposed to high environmental temperatures, resulting in performance and reliability degradation. It is thus important to monitor the temperature at the junction, which is a primary lighting and heat source, especially for an LED operated under a high-temperature environment. In this study, the temperatures at the junction, phosphor, and thermal pad of the LED operated at high temperatures (up to 107.2 °C) are measured and analyzed. The junction temperature is measured by a transient thermal tester at known environmental temperatures and input currents. Moreover, the temperatures at the phosphor and thermal pad are simultaneously measured by using an infrared (IR) thermometer and a thermocouple, respectively. A single highly linear temperature correlation (R2 = 0.997) is found between the junction and phosphor temperatures regardless of the operating conditions. This could aid in precisely estimating the junction temperature by simply measuring the surface temperature of phosphor. On the other hand, the correlation between the junction and thermal pad temperature that is often treated as a single correlation exhibits dependence on the input current over the tested temperature range. The structural thermal analysis on the thermal resistance of the LED package supports the experimental results along with the numerical analysis. The obtained results in this study could provide a set of guidelines for the precise prediction of junction temperature and thermal management of LEDs, which are operated under high-temperature environments.

中文翻译：

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通过对在高环境温度下工作的发光二极管进行热分析来精确测量结温

摘要 发光二极管 (LED) 已成为许多应用中很有前途的固态光源。在运行过程中，它们经常暴露在高环境温度下，导致性能和可靠性下降。因此，监测结点处的温度非常重要，结点是主要的照明和热源，特别是对于在高温环境下运行的 LED。在这项研究中，测量和分析了在高温（高达 107.2 °C）下运行的 LED 的结、荧光粉和导热垫的温度。结温由瞬态热测试仪在已知环境温度和输入电流下测量。此外，荧光粉和导热垫的温度是通过使用红外 (IR) 温度计和热电偶同时测量的，分别。无论工作条件如何，结点温度和荧光粉温度之间都存在单一的高度线性温度相关性 (R2 = 0.997)。这可以通过简单地测量磷光体的表面温度来帮助精确估计结温。另一方面，结点和散热垫温度之间的相关性通常被视为单一相关性，在测试温度范围内表现出对输入电流的依赖性。LED 封装热阻的结构热分析支持实验结果以及数值分析。本研究中获得的结果可以为精确预测在高温环境下运行的 LED 的结温和热管理提供一套指导方针。无论工作条件如何，结点温度和荧光粉温度之间都存在单一的高度线性温度相关性 (R2 = 0.997)。这可以通过简单地测量磷光体的表面温度来帮助精确估计结温。另一方面，结点和散热垫温度之间的相关性通常被视为单一相关性，在测试温度范围内表现出对输入电流的依赖性。LED 封装热阻的结构热分析支持实验结果以及数值分析。本研究中获得的结果可以为精确预测在高温环境下运行的 LED 的结温和热管理提供一套指导方针。无论工作条件如何，结点温度和荧光粉温度之间都存在单一的高度线性温度相关性 (R2 = 0.997)。这可以通过简单地测量磷光体的表面温度来帮助精确估计结温。另一方面，结点和散热垫温度之间的相关性通常被视为单一相关性，在测试温度范围内表现出对输入电流的依赖性。LED 封装热阻的结构热分析支持实验结果以及数值分析。本研究中获得的结果可以为精确预测在高温环境下运行的 LED 的结温和热管理提供一套指导方针。