全息波导显示系统中输出光栅的优化

Abstract

In a holographic waveguide display system,the diffraction efficiency,location,and length of each ouput grating make great impact on the uniformity of output intensity and ratio of energy utilization.Generally uniformity of output intensity is decided by the diffraction efficiency distribution of each output grating,and ratio of energy utilization rests with the location and length of each ouput grating.Firstly,aming at the uniformity of central field of view,the diffraction efficiency distribution of corresponding output grating was optimized and curve fitting,and a continuous and increasing curve of efficiency distribution was obtained.Similar processing was carried out for other gratings corresponding to other FOV.Calculation results demonstrate that the uniformity of output intensity of HWDS will be improved notablely when output gratings with optimized continuous and increasing diffraction efficiency distributions are used than that of traditional output gratings with step diffraction efficiency distributions.A shifting-optimization method was proposed to optimize the location of each grating according to the size of exit pupil and usage distance,so that the ratio of energy utilization of HWDS could be greatly incereased resulted from the reduction of the invalid diffraction region.