P‐8.6: Methods of Ghost Measurement and Mitigation in Virtual Reality Pancake Optical System

In the VR optical system, the pancake optics faces the problem of ghost, which is more serious than the conventional aspherical/Fresnel optics. The causes of pancake ghosts are different, thus the performance of pancake ghosts in the image is also different. Some of them can be clearly imaged, but some exist in the form of light spots. The presence of these ghosts seriously affects the image contrast. In this paper, ghost measurement and simulation methods are proposed, which obtains the Virtual image distance, position and brightness of the ghost image, and the cause of the ghost image is obtained by combining the simulation and measurement. Finally, ghost intensity was reduced from 4.68% to 2.39% using the ghost image mitigation methods. A pancake optical system was optimized and prototype was demonstrated, with a field of view of 108°, an exit pupil diameter of 10mm, and a ghost image intensity of less than 2.39%.