激光扫描头戴式增强现实系统中带斑抑制与中继光路设计

Banding Suppression and Relay Optical Path Design for Laser Scanning Head-Mounted Augmented Reality System

为了抑制在头戴式增强现实显示系统中激光扫描(LBS)与光栅光波导直接耦合时产生的带斑(Banding)现象并改善系统的最终成像效果,首先介绍了Banding现象,分析讨论了Banding现象产生的具体原因。随后,提出了一种加入扩散片的扩束抑制方法,并通过扩束光路结构验证了其可行性。针对抑制方案进行了小尺寸、大视场中继光路的设计优化,以满足其在头戴式增强现实显示系统中的应用。本设计的系统总长小于25 mm,在截止频率43 lp/mm处,前端与后端各视场的调制传递函数值均大于0.3,畸变均小于±2.2%,满足设计的各项指标需求。所提方法可以有效抑制LBS与光栅光波导配合使用过程中的Banding现象,因此为基于LBS的头戴式增强现实显示系统的研究提供了一定的参考价值,具有潜在的应用前景。

To suppress the Banding phenomenon generated when the laser beam scanning(LBS)and grating optical waveguide are directly coupled in the head-mounted augmented reality display system and improve the final imaging effect of the system,the Banding phenomenon is first introduced,and the Banding phenomenon is analyzed and discussed.Then,a beam expanding suppression method with a diffuser is proposed,and its feasibility is verified by the beam expanding optical path structure.Aiming at the suppression scheme,the design optimization for the small-size and large-field-of-view relay optical path is carried out to meet its applications in the head-mounted augmented reality display system.The total length of the designed system is less than 25 mm.At the cut-off frequency of 43 lp/mm,the modulation transfer function values of the front-end and back-end fields-of-view are greater than 0.3,and the distortion is less than±2.2%,which meets the requirements of various indicators of the design.The proposed method can effectively suppress the Banding phenomenon in the process of coupling between LBS and grating optical waveguide.Therefore,this work provides a certain reference value for the research of the head-mounted augmented reality display systems based on LBS and has potential application prospects.