15.3: Two‐Dimensional Exit‐pupil Expansion in Augmented Reality (AR)

Abstract

The key requirements of Augmented Reality (AR) optical modules are wearability and image quality. However, the two aspects are like two facets in the same dice, often contradicting each other due to the restriction of physics. The emergence of optical waveguide technology is expected to solve the above-mentioned problems. Among them, the reflective waveguide has attracted much attention due to its excellent image quality and high efficiency. Especially, the two-dimensional exit-pupil expansion technology can further alleviate the conflict between wearability and image quality. In this work, we first introduced the principle of two-dimensional exit-pupil expansion. Then, we proposed a butterfly-shaped two-dimensional reflective waveguide, which can achieve a larger field of view and eye box in a smaller volume compared to the traditional two-dimensional reflective waveguide. Finally, we exhibit the experimental data of the butterfly-shaped two-dimensional reflective waveguide and the traditional two-dimensional reflective waveguide to show the improvement.