白光發光二極體(White LED) 是新一代重要的固態照明設備。了解其中的電、光、熱的交互作用機制是我們非常中要的課題。本研究中使用有限元素分析法搭配蒙地卡羅法建立光電熱耦合數值模擬分析模型。透過內部量子效率計算光源能量分布。再套入螢光粉封裝數值模型分析螢光粉轉換白光LED整體封裝的溫度場分布、出光能量、相對色溫及演色性。 本研究選用藍光LED以及黃光螢光粉作為組成白光LED的方式。同時探討藍光與白光LED。所有的模擬結果與實驗結果比較都有非常高的一致性。並證實螢光粉層的自加熱效應是造成螢光粉層熱點的主因。 根據此驗證模型提出雙層螢光粉封裝設計方式。限定內層螢光粉的濃度一定高於外層的螢光粉，並將相對色溫定在6300K左右。在有較高的內層螢光粉濃度時，因為LED本身的吸收上升而導致顏色的偏差與接面溫度的上升。較低的內層螢光粉濃度時，會有較低的接面溫度，然而因為大部分的熱源發生在外層，也因此有較高的螢光粉層溫度。 ;White LED is an important candidate of new generation solid state lightening. Understanding the mechanism of how is the interaction between current, light and heat is an essential task for us. In this study, finite element method (FEM) and Monte Carlo statistics method are applied to optical-electrical-thermal coupled numerical model. Obtaining the light source from IQE calculation. Coupling with the phosphor packaging numerical model in order to analyze the temperature distribution, light output power, CCT, and CRI of phosphor-converted white LED. The blue LED and yellow phosphor is chosen as the material of white LED. The packaging with and without phosphor are investigated. From the comparison, the result obtained from numerical simulation can correctly fit to the experimental result. The self-heating of phosphor layer is the main reason that caused the hotspot in phosphor layer for phosphor-converted white LED. Based on the previous analysis, double phosphor layer packaging was proposed. The concentration of inner layer is always higher than outer layer, and the CCT of white LED is set to be about 6300K. With higher inner concentration, the absorption of die is enhanced, caused the color shift and higher junction temperature. Lower inner concentration can lead to lower junction temperature, however the maximum temperature of phosphor layer is higher as an exchange, due to the heat generation mostly happened at outer layer. Based on these analysis of simulation, better LED device is expected to be realize.
