大出瞳自由曲面头盔显示器光学系统的设计

Design Method of a Free-form HMD System with Large Pupil Size

头盔显示器系统由于自身对尺寸和重量有严格要求,采用自由曲面器件可以起到减少透镜片数,从而缩小系统尺寸、减轻重量等作用.针对目前单片式自由曲面棱镜解决方案存在的出瞳直径小,棱镜自由曲面光学面加工定位困难等问题,介绍了一种大出瞳自由曲面头盔显示器光学系统的设计方法,并给出了设计结果.设计方案采用了自由曲面棱镜和薄透镜的双片式结构,棱镜和薄透镜都各自含有一个平面光学面,有效降低了加工难度,同时薄透镜与显示器可以作为一个整体调整,不增加装调难度,采用0.61寸微型显示器,对角视场45°,出瞳直径达到了10 mm.

Usually,free-form optical surfaces do not have rotational symmetry compared with traditional spherical and aspheric elements,so they have more freedom for system design.In some optical systems which have strict package requirements,such as overall length,weight and volume etc.,free-form optical elements can help to satisfy these requirements through reducing lens number of the system.In this paper,the design method of free-form optical elements was introduced,and proposed several design examples of the optical system were proposed which adopted free-form optical elements.From these design examples,the advantages of using free-form optical elements could be proved.The size of the micro-display used is 0.61 inch and FOV is 45°.The exit pupil diameter is 10 mm.