新型波导型准直投影系统中衍射光栅的设计

Design of Diffraction Grating in New Type of Waveguide Collimated Projection System

新型波导型准直投影系统利用衍射光栅,仅使用一块波导板即可完成光束的耦合、扩展和成像,更利于系统集成和小型化,具有很高的研究价值。基于严格耦合波理论建立了新型波导型准直投影系统中衍射光栅的Matlab模型,并根据系统对衍射光栅的性能需求,对耦合光栅、扩展光栅和出射光栅的模型进行分析,设计衍射光栅的结构及相关参数。结果表明,采用新型闪耀光栅作为耦合光栅,扩展光栅设计为普通二元光栅和新型二元光栅相结合,采用闪耀光栅作为出射光栅,所得的新型波导型准直投影系统成像均匀,视场为24.8°×30°,系统占用空间小、质量轻,可用于集成和小型化的显示器。

A new type of waveguide collimated projection system uses diffraction grating, which can complete the beam coupling, expansion and imaging by only using one waveguide plate. So it is more conducive to system integration and miniaturization, and it has great research value. A Matlab model of the diffraction grating in the new type of waveguide collimated projection system is established based on the rigorous coupled wave theory. According to the performance requirements of the system, the models of the coupled grating, extended grating and exit grating are analyzed, and the structure and related parameters of the diffraction grating are designed. The results show that the new blazed grating is used as the coupled grating, and the extended grating is designed as a combination of traditional binary grating and novel binary grating, while the output grating is a blazed grating. The waveguide collimated projection system is uniformly imaged, whose field of view is 24.8°× 30°. The system can be used for the integrated and miniaturized displays with small occupation and light weight.