P‐4.6: Curved augmented reality display using printed freeform holographic optical element

We propose a methodfor designing and fabricating freeform HOEs on curved optical substrates that can be utilized to implement curved augmented reality (AR) displays. Compared with conventional HOEs, freeform HOEs can enhance image performance and enlarge degrees of freedom in design. In our method, the phase profiles of the freeform HOE on the curved surface are first optimized to achieve good image performance. Then, recording wavefronts are optimized to improve uniformity of diffraction efficiency and converted into wavefronts for a planar substrate. The conversion relationship between curved HOEs and planar HOEs is analyzed. A holographic printer has been developed for fabricating freeform HOEs on a flat substrate temporarily, which are then pasted onto the curved substrate. A simple application case of curved freeform HOE is presented to demonstrate the effectiveness of the proposed method.