传统的两层棱镜膜对于MiniLED背光的增亮效果不明显, 因此设计了一种微结构薄膜来代替两层棱镜膜。首先, 根据MiniLED背光的配光曲线及尺寸, 对微结构进行分段设计。将与MiniLED芯片等宽区域设定为顶角90°的棱柱结构, 对2个MiniLED芯片之间的区域, 将MiniLED芯片作为扩展光源, 芯片2个端点发出的光束到达微结构底面会形成一个夹角, 将夹角的角平分线处光线准直到轴向方向, 结合Snell定律进行计算, 得到棱柱微结构倾角。然后, 通过LightTools仿真软件对单个微结构及微结构阵列分别进行了建模和仿真, 仿真结果表明: 加微结构薄膜后的轴向视角亮度相比于加两层棱镜膜提升了31.3%。最后, 通过无掩模光刻设备对设计的微结构薄膜进行加工制备, 并对样片进行测试。实测结果表明: 加微结构薄膜后的轴向视角亮度相较于加两层棱镜膜提升了25.7%。实现了针对MiniLED背光模组的亮度增强设计。

As the fact that the traditional two-layer prism films can not enhance the brightness of the MiniLED backlight obviously, a thin film with microstructure was designed to substitute for two-layer prism films.Firstly, based on the luminous distribution and the size of the MiniLED die, the microstructure was designed into two parts. For the region as wide as MiniLED die, the microstructure was designed as the prism with 90°vertex. For the region between the two MiniLed dies, the MiniLED die was taken as an extended source and the light emitted from the two endpoints of the MiniLED die reached a certain point of the microstructure and formed an angle. The light along the bisector was collimated to the axial direction. The microstructural profile was calculated combining the Snell’s law. After that, a single microstructure and array were modeled and simulated by LightTools. The simulated results show that the on-axis brightness increases by 31.3% compared with the two-layer prism films. Finally, the microstructure was fabricated by the maskless lithography device and tested by cofocal microscope. The experimental results show that the on-axis brightness increases by 25.7% compared with two-layer prism films. The thin film can help enhance brightness of MiniLED backlight module.