Retinal projection displays (RPDs) are an important development direction for head-mounted displays (HMDs). This paper reviews the literature on optical engineering aspects based on the data on advanced technology in RPD design and development. The review includes the principles and applications of four theories, e. g., the Maxwellian view and its modified modality and the monocular and binocular depth cues of stereoscopic objects in the physiology of the human visual system. To support the Maxwellian view and achieve retinal projection systems with depth cues, results of previous design works were summarized using different methods and their advantages and disadvantages are analyzed. With an extremely long focal depth, a prototype of a full-color stereoscopic see-through RPD system was discussed. Finally, a brief outlook of the future development trends and applications of the RPDs was presented.

针对传统透射型头盔显示器在眼睛调节焦距时，二维虚拟信息在视网膜上无法清晰成像问题，提出一种新型的透射型头盔显示器。采用麦克斯韦观察法原理，用微型LCD结合激光直接将图像成像到视网膜上，成像面独立于眼睛的调节，其目的是眼睛在调节过程中，图像总是清晰的。讨论了透射型头盔显示器显示原理，根据系统参数选择合适的初始结构，设计了光学系统，根据系统整体结构对混合现实的需要，加入半透半反结构，通过ZEMAX软件对系统进行优化。最后对系统功能做了验证，结果表明系统轴上视场MTF达到了衍射极限。