从荧光粉散射机理分析了LED器件色角向分布不均匀的形成原因, 提出了一种利用逐点步进光学设计方法, 实现了不同入射角度内蓝光光程相等的远荧光粉层结构。应用该方法设计了使用不同折射率载体的LED远荧光粉层光学结构。模拟结果显示, 应用所设计的光学形状的远荧光粉层结构, 相比传统平面荧光粉层结构, 75°方向光斑边缘与中心法线方向色差du′v′从0.05降低到0.01左右, 色温偏移降低了43%~98%不等, 有效改善了白光LED远程荧光粉封装结构的色度均匀性。该设计不需要增加或改变封装工艺手段, 工业生产实现简单, 额外成本很少, 具有较强的实际应用价值。

With demonstration of the reason for LED color angular distribution uniformity by analyzing the scattering mechanism of phosphor, proposed was an optical design method for the phosphor layer with the thought of “equal optical distance with different rays from LED”. Applying the optical design with non-imaging optical design method point by point, different shapes of phosphor layer with different diffraction index substrates were designed. Compared to remote phosphor LED with conventionally planer-shaped phosphor layer, the color difference du′v′ measured from edge of light spot which was 75° apart from normal direction to center of LED light spot, was reduced from around 0.05 to 0.01, as well as CCT difference declined from 43% to 98% on different target color temperatures. This work has good practical values in industry because the LED devices do not need extra encapsulation technologies and bring no extra expenses.