A Luminance Uniformity Modulation Procedure for Grating-based Exit-pupil Expander

A luminance uniformity modulation procedure is proposed for grating-based exit-pupil expander (EPE) using in waveguide display. Whereas the diffractive efficiency of the extracted light via coupling-out structure area (COSA) has been analyzed by both rigorous coupled wave analysis (RCWA) and finite difference time domain (FDTD) wave optics theory in RSoft®. We have also imported bidirectional scattering distribution function (BSDF) file into waveguide optical system using LightTools® to validate the desired purpose. The luminance uniformity results of 5 COSAi have been achieved excellent performance 99.44% with a good overall light extracting rate 19.27 % and no optical crosstalk issue has occurred.