基于新型导光管的微型DLP投影式光路设计

Optical design of micro DLP projection based on novel light pipe

传统的数字光处理(DLP)技术无法收集利用数字微镜(DMD)芯片上微镜处于"OFF"态时反射的光线,针对这种缺陷,提出一种基于新型导光管的微型DLP投影光学系统的设计方案,该系统包括LED、导光管、色轮、准直系统和投影透镜。提出在锥形导光管的基础上加上一根弯型的导光管和复合抛物面聚光器(CPC)用来收集被DMD反射的多余的光线。先用非成像光学的理论分析和计算出各部分的相关参数,再用ZEMAX软件对准直系统和投影透镜进行结构优化,最后用Trace Pro软件建立模型并仿真,仿真结果表明:随着"OFF"态微镜数量的增加,收集光管提高系统光能利用率的能力先增加后减小。相比没有收集光管的情况,当DMD芯片上处于"OFF"态微镜数量为50%时,导光管提高的光能利用率最多,为5.91%。

Traditional DLP technologies can not collect and utilize the light which is reflected by the micromirrors of DMD in the ＂OFF＂ state. Aiming at this defect, one design scheme of the micro DLP projection system based on a novel light pipe was presented. This system included LEDs, light pipe, color wheel, the collimation system and projection lens. A bending light pipe was added on the base of the tapered light pipe, and a compound parabolic concentrator （CPC） was used in the input end to collect the extra light reflected by the DMD. First, the related parameters of each part were analyzed and calculated according to the nonimaging optics theory. Second, the collimation system and projection lens were optimized by ZEMAX software. Finally, the model was built and simulated in TracePro software. The simulation results show that： with the number of micromirrors in the ＂OFF＂ state growing, the improving light efficiency ability of collecting light pipe first increases then decreases. Comparing with having no collecting light pipe, the light efficiency is increased by 5.33%; light pipe improves the most light efficiency, 5.91%, when half of the micromirrors are in the ＂OFF＂ state.