The correlated color temperature (CCT) variation of the phosphor-converted light-emitting diodes (LEDs) after curing is a common phenomenon. In the past, it was believed that the phenomenon was caused by the sedimentation of phosphor particles. However, not only sedimentation, but these particles can also flow with the natural convection of silicone because of nonuniform heating during curing. The convective flow of the phosphor particles during curing was studied in detail in this work. The CCT variation and phosphor particles flow in the LED device cup with different depths and wall inclination angles were studied. The results show that the CCT increases after curing when the depth of the device cup is shallow. The case is the opposite when the depth of the device cup is deep. The convective flow behaviors of the silicone were revealed in the simulation. The large-angle inclined wall can increase the silicone flow path length and inhibit the particles flow downward caused by the flow to a certain extent. It is envisioned that the findings will strengthen the understanding of the CCT variation phenomenon and guide the encapsulation structure design of LEDs for better color quality.

中文翻译：

---

有机硅固化过程中荧光粉颗粒对流行为及其对白光LED光学性能影响的研究


荧光粉转换发光二极管（LED）固化后的相关色温（CCT）变化是一种常见现象。过去，人们认为这种现象是由荧光粉颗粒沉降引起的。然而，不仅会沉淀，而且由于固化过程中加热不均匀，这些颗粒还会随着有机硅的自然对流而流动。这项工作详细研究了固化过程中荧光粉颗粒的对流流动。研究了不同深度和壁倾角的LED器件杯中的色温变化和荧光粉颗粒流动。结果表明，当器件杯的深度较浅时，固化后色温会增加。当装置杯的深度较深时，情况相反。模拟中揭示了有机硅的对流流动行为。大角度斜壁可以增加硅胶流路长度，在一定程度上抑制流动造成的颗粒向下流动。预计这些发现将加强对 CCT 变化现象的理解，并指导 LED 的封装结构设计，以获得更好的色彩质量。