针对投影显示系统中变焦投影机构结构复杂、需要手动调节等不足,设计了一种基于LCoS空间光调制器的可变焦投影显示系统。在DMD投影系统中添加LCoS空间光调制器取代传统的光学变焦透镜组,利用LCoS的相位调制特性在LCoS中加载所需透镜的理想相位灰度图,实现对投影图像的调制。实验结果表明:加载相位调制因子的LCoS空间光调制器可实现投影系统中的数字变焦透镜作用,同时调制因子可动态改变,系统能够实时实现图像的大小调整和位置平移。该系统无机械运动结构、全电化,具有很好的鲁棒性。

A new variable focus projection display system based on LCoS spatial light modulator is designed for the complex structure of the zoom projection mechanism in the projection display system and the need for manual adjustment. LCoS is added in the DMD projection system to replace the traditional optical zoom lens group. According to the phase modulation characteristics of LCoS, the phase gray images of the required lens are generated and loaded to the LCoS to achieve the modulation of the projection images. The experimental results show that the LCoS SLM loading phase modulation factor can effect as a digital zoom lens in projection system. Meanwhile the modulation factor can be changed dynamically, and the system can realize real-time adjustment of image size and position translation. The system has no mechanical movement structure, all-electronics, and has good robustness.