Design and fabrication of curved waveguide display based on freeform polarization volume holograms

As one of the most promising augmented reality solutions, waveguide display has attracted widespread attention in recent years. However, most existing research and commercial products are limited to the planar waveguide scheme. Here, we propose a curved waveguide scheme using freeform polarization volume holograms (F-PVHs) as couplers. The design of this scheme relies on cooperative optimization after the coupler is unfolded. Due to the high degrees of design freedom of F-PVHs, the proposed scheme can accurately correct the aberrations of the curved waveguide with a wide field of view while improving the brightness uniformity of the imaging. The designed curved waveguide display can be conveniently obtained using the proposed fabrication process of flexible and transferable F-PVHs. The designed waveguide systems with 1D and 2D exit pupil expansion are presented respectively. The effectiveness and superiority of our design method are demonstrated through high-resolution imaging results with a wide field of view and large eye box in simulation. Furthermore, the waveguide sample and the display prototype are prepared to prove the feasibility of the proposed scheme. Finally, we discuss the current shortcomings and scalability of this scheme, hoping to pave the way for the development of high-performance curved waveguide displays.