OLED外发光效率增强模型研究

提高OLED的外发光效率对于长寿命、低功耗的OLED显示器和有机发光光源尤为重要。利用几何光学模型计算了OLED典型结构的外发光效率，结果表明仅有18%的光成为外输出光，主要的光损失来自OLED器件内的光波导效应。提出了一种理想的圆台结构OLED光输出增强模型，处于圆台顶的发光面发出的光线经侧面反射后成为外输出光，有效反射面越大，光输出增强效果越明显。有效反射面的大小取决于圆台侧壁质量和圆台半锥角及其高度。对该结构的优化进行了详细讨论。

Truncated cone model for OLED external quantum efficiency enhancement

It is very important to improve the external quantum efficiency of OLED for several applications such as organic light source and the flat panel display, which is long lifetime and low power consumption. The light extraction factor of 18% in planar OLED is predicted by classical ray optics model. The optical losses are mainly from the waveguiding effect-edge emission of waveguided modes. A ideal light output model of truncated cone geometry for OLED is provied.The light emitted from the top mesa surface becomes the external output light by reflecting through the wall. The more the effective reflective surface, the more the light output enhancement. The effective reflecting surface is related to wall quality,half core angle and the mesa height. An optimal geometry is discussed.