基于视网膜投影显示的头盔显示器设计

Helmet-mounted displays based on retinal projection display

传统的透射型头盔显示器虽然可以显示虚拟图像,但当眼睛调节焦距时无法清晰显示虚拟图像,研究一种新型的透射型头盔显示技术,其特点是既可以看到外部景物,也可以同时看到微型显示芯片上所显示的虚拟图像,并且虚拟图像独立于人眼的调节。介绍显示技术的原理,用光学设计软件Zemax完成整体光学系统设计,优化后系统达到衍射极限,滤波投影系统中MTF在60lp/mm处达到了0.7;用Autocad软件设计了头盔显示器结构。光路成像实验结果表明:设计的系统可以看到外界图像和虚拟图像,当眼睛对外界景物聚焦时,外界景物与虚拟图像都保持清晰,眼睛对外界景物离焦时,外界景物变得模糊而虚拟图像仍然保持清晰。

Conventional see-through head-mounted displays can display virtual image; however, virtual image can not keep clear on the retina from beginning to end when the eyes adjusts the focus length. So a new technology of see-through head-mounted displays which can catch sight of external features and see the virtual image on the micro-display chip has been introduced. It is an advantage of virtual image, which can always keep clear, no matter how to adiust the fo- cus of eyes. The principle of display technology was discussed. The overall optical system was designed by using Zemax and reached the diffraction limit after optimization. The MTF of filte- ring projection system was 0.7 at 60 lp/mm. The structure of head-mounted displays was de- signed by Autocad. The imaging experiment result shows that both the external features and the virtual image could be seen clearly in the presence of eyes focusing on external features. Though the external features would be fuzzy when eyes defocus on external features, the virtu- al image could still be seen as clearly as before.