Advanced 3D AR display based on custom-designed asymmetric holographic microlens array with high fill factor

This study presents a novel approach for enhancing three-dimensional (3D) augmented reality (AR) displays through the custom-designed asymmetric holographic microlens array (A-HMA). The A-HMA is specifically designed to enhance the performance of AR display system by balancing spatial resolution, field of view (FOV), and fill factor. It ensures uniform diffraction for a solid volumetric beam profile while maintaining a smooth 3D effect. During the fabrication process, a computer-generated hologram (CGH) pattern of the concave phase profile is generated and employed in conjunction with fully automated holographic wavefront printing. The digitally computed microlens function is sequentially recorded onto a single thin HOE plate through holographic wavefront printing at the precise micro-scale, ensuring a high fill factor and uniformity, both of which are essential for high-quality AR visualization. The asymmetrical structure of the hexagonal hogel layout, precisely fabricated via the holographic wavefront printing system, enhances both packing density and angular coverage, thereby contributing to improved light efficiency and spatial sampling performance. For seamless and realistic 3D scene reconstruction, a hexagonal elemental image array is generated using a direction-inversed propagation algorithm based on computer-generated integral imaging. This algorithm is optimized for the fabricated A-HMA, ensuring efficient computation and accurate reconstruction of real-world objects in the AR display. The proposed 3D AR system successfully reconstructs volumetric 3D scenes with high clarity, providing an immersive AR experience. Experimental results validate the effectiveness of this system, demonstrating its potential for next-generation AR display applications.