Aberration-free warp projection on a horopter screen using freeform holographic optical elements

A horopter screen has been popularly studied since its curvature reduces the parallax between two eyes and the immersive displays with a horopter-curved screen are regarded to provide vivid impression of depth and stereopsis. But, the projection on a horopter screen causes some practical problems that the image is hard to be focused on the entire screen and its magnification is partially different. An aberration-free warp projection has a great potential to solve these problems, which changes the optical path from an object plane to an image plane. Since the variation of the curvature is severe in the horopter screen, a freeform optical element is required for an aberration-free warp projection. In comparison with the traditional fabrication method, the hologram printer has the advantage of rapidly manufacturing free-form optical devices by recording the desired wavefront phase on the holographic medium. In this paper, for a given arbitrary horopter screen, the aberration-free warp projection is implemented with the freeform holographic optical elements (HOEs) fabricated by our tailor-made hologram printer. We experimentally demonstrate that the distortion and defocus aberration are effectively corrected.